Drivetrain jerk

[Dave LV]

OK, so my windshield noise and driver side rattling are on this board.

How about has anyone noticed the drivetrain jerking once when slowing down from highway speeds, kinda like the center differential finally unlocking.

[wannabeH3]

yes, i get it when slowing down then getting on the gas again... i figure its normal....

[RubHer Yellow Ducky]

Have 2 H-3's.

One has same as you described, the other shows no problem. Have around 3000 miles on it and taken it up to around 85 mph a few times so from school zones to 85 experience no jerking. I use CRUISE whenever possible so would notice it...

RYD

[Hummer crazy]

yes I have it Too guess its just a trait of the H3,( lest i hope)

[Mike E]

I get the same jerk. I figured it was a normal response in the auto trans.

[phantom2]

Same situation here...

[Steve - SanJose]

I sometimes get a bit of it, feels like a bit of driveline lash. But it's a truck not a car.

S.

[ChevyHighPerformance]

Does it feel like the torque converter is unlocking?

[HummBebe]

Originally posted by wannabeH3:
yes, i get it when slowing down then getting on the gas again... i figure its normal....

Honest, I did not have this issue before I had my 15000 mile trnsmission service. Now it makes me crazy. Is this possible??

[1COOLH3]

Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by wannabeH3:
yes, i get it when slowing down then getting on the gas again... i figure its normal....

Honest, I did not have this issue before I had my 15000 mile trnsmission service. Now it makes me crazy. Is this possible?? </div></BLOCKQUOTE>

[1COOLH3]

Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by wannabeH3:
yes, i get it when slowing down then getting on the gas again... i figure its normal....

Honest, I did not have this issue before I had my 15000 mile trnsmission service. Now it makes me crazy. Is this possible?? </div></BLOCKQUOTE>


Who ripped you off for a transmission service already?
Even with heavy duty use it's not recommended to do a trans service until 50k.

HUMMER H3 Maintenance Schedule
Automatic Transmission Fluid and Filter Replacement
Replace the automatic transmission fluid and filter
Interval: Every 100,000 miles unless the vehicle is mainly driven under one or more of these conditions: 1) In heavy city traffic where the outside temperature regularly reaches 90 F (32 C) or higher, 2) In hilly or mountainous terrain, 3) When doing frequent trailer towing, and 4) Uses such as found in taxi, police or delivery service. If vehicle is driven under these conditions, change every 50,000 miles.

[HummBebe]

Originally posted by 1COOLH3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by wannabeH3:
yes, i get it when slowing down then getting on the gas again... i figure its normal....

Honest, I did not have this issue before I had my 15000 mile trnsmission service. Now it makes me crazy. Is this possible?? </div></BLOCKQUOTE>


Who ripped you off for a transmission service already?
Even with heavy duty use it's not recommended to do a trans service until 50k.

HUMMER H3 Maintenance Schedule
Automatic Transmission Fluid and Filter Replacement
Replace the automatic transmission fluid and filter
Interval: Every 100,000 miles unless the vehicle is mainly driven under one or more of these conditions: 1) In heavy city traffic where the outside temperature regularly reaches 90 F (32 C) or higher, 2) In hilly or mountainous terrain, 3) When doing frequent trailer towing, and 4) Uses such as found in taxi, police or delivery service. If vehicle is driven under these conditions, change every 50,000 miles. </div></BLOCKQUOTE>

I'm sorry, I meant transfer case and rear diff. The tech checked them and said they had to be serviced. Did they burn me??? I find it hard to believe.

[Edspad]

Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 1COOLH3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by wannabeH3:
yes, i get it when slowing down then getting on the gas again... i figure its normal....

Honest, I did not have this issue before I had my 15000 mile trnsmission service. Now it makes me crazy. Is this possible?? </div></BLOCKQUOTE>


Who ripped you off for a transmission service already?
Even with heavy duty use it's not recommended to do a trans service until 50k.

HUMMER H3 Maintenance Schedule
Automatic Transmission Fluid and Filter Replacement
Replace the automatic transmission fluid and filter
Interval: Every 100,000 miles unless the vehicle is mainly driven under one or more of these conditions: 1) In heavy city traffic where the outside temperature regularly reaches 90 F (32 C) or higher, 2) In hilly or mountainous terrain, 3) When doing frequent trailer towing, and 4) Uses such as found in taxi, police or delivery service. If vehicle is driven under these conditions, change every 50,000 miles. </div></BLOCKQUOTE>

I'm sorry, I meant transfer case and rear diff. The tech checked them and said they had to be serviced. Did they burn me??? I find it hard to believe. </div></BLOCKQUOTE>
Probuly not, Ive seen the way you wheel sister. there is a slight mad glint in your eyes as you have blown past me on obstacles, Tranny screaming in pain and Diffs glowing hotter than the day they were forged. Sounds about right http://www.elcova.com/infopop/emoticons/icon_wink.gif

[Dave LV]

Originally posted by ChevyHighPerformance:
Does it feel like the torque converter is unlocking?

No [YES!] because that occurs right around 39 mph. This can occur at lower speeds after driving at highway speeds [I rechecked, and it is right at 39 mph]. Definitely more like the center dif is unlocking, but I just don't know [yep, torque converter unlocking]. Not a big thing, but a quirk of the H3.
[I am surprised that the H3 torque converter does not unlock when the brakes are pressed - or am I misreading it?]
[modified 3/27/06]

[HummBebe]

Probuly not, Ive seen the way you wheel sister. there is a slight mad glint in your eyes as you have blown past me on obstacles, Tranny screaming in pain and Diffs glowing hotter than the day they were forged. Sounds about right Wink



LMAO ED..... http://www.elcova.com/infopop/emoticons/icon_biggrin.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

[HummBebe]

Seriously though, what could it be??? After decellerating, when you begin to accellerate, there is a deep sounding (like when you forget to downshift and try to take off....lugging the engine) clunk/jerk before it will shift down to accellerate.Usually around 2000 RPM's.

I know the "hunting" thing is normal for GM....but again, this didn't start until I had the T-Case/Rear diff serviced.

Also, when I did have the T-case serviced, I went to pick it up, and as I drove down the street, (after hours of course) it would not shift out of first http://www.elcova.com/infopop/emoticons/icon_mad.gif So I had to leave it there and come back the next morning. They fixed
it quickly and sent me on my way.

They forgot to reconnect the "shift soleniod"??? (I can't remember exactly)

Am I making any sense???


I would like to resolve this before I head out to Moab. If it is not a big deal, I can wait.

Thanks in advance for your help.

Bebe

[Edspad]

Go Back to the service dept, make a point of one of the tech's going with you on a test drive
tell'em you want a explanation written. if there is a quirk in software or even an issue on the build out of a mechanical device, Most of the time the factory will send out tech reports on the problem. dont let'em walk on ya...push your chest out and roll the corner of your lip over a tooth
There must be an explanation !! http://www.elcova.com/infopop/emoticons/icon_rolleyes.gif
.
.
Is your Pony Car a Auto or a Manual?

[HummBebe]

Originally posted by Edspad:
Go Back to the service dept, make a point of one of the tech's going with you on a test drive
tell'em you want a explanation written. if there is a quirk in software or even an issue on the build out of a mechanical device, Most of the time the factory will send out tech reports on the problem. dont let'em walk on ya...push your chest out and roll the corner of your lip over a tooth
There must be an explanation !! http://www.elcova.com/infopop/emoticons/icon_rolleyes.gif
.
.
Is your Pony Car a Auto or a Manual?

Teh Pony is a manual, we've put on a CAI, Exhaust and a Super Chip.....yee haw!!!!! We are at 380hp, 425tq. She scoots just a little. http://www.elcova.com/infopop/emoticons/icon_biggrin.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

push your chest out and roll the corner of your lip over a tooth

What a visual.....Tanks Ed!

[UNOMYFLO]

I have the same jerk, when crusing on the hwu at like 65 when I come up on traffic and let up on the gas then hit the gas again there is definately a jerk as the truck accelerates again.

I think it can be 2 things:

First thought i have is the throttle is electronic controlled by the computer the accel and decell is not fluid perhaps it is in the programming.

My 05 dodge ram hemi laramie had an electronic throttle and did not do this.

the secone thing I thought it could be is perhaps to much play in the ring and pinion in the rear end, it feels as though there is play in it and this is the reason for the jerk. When crusing and having the accel depressed the rear gears are under preload when the foot is taken off the gas the preload goes away finding the play in the gears when the foot is back on the gas the gears find preload and during thsi time is the jerk.

Seems like a lot of us have it which is good as if this becomes a problem in the futurew the warantee will kick in intil then it annoys me but I figure is it ****s the bed I will bring it in.

UNO

[UNOMYFLO]

Oh I have 4500 on the odo by the way and it did it right out of the box new.


I bet it is the electronic throttle...perhaps it can be recalibrated through the computer to have tighter tollerances and a tighter feel on and off the gas..

would be nice anyway

[BABHUMV]

If this driveline slap occured after the service, I would suggest returning and having them make sure they have the proper amount of fluid. It is possible no/low fluid could cause this to happen.

[Kracker]

Mine has it too.

[Steve - SanJose]

Speaking of dealer prescribed overmaintenance, my dealer tried to sell me a $399 15,000 service at 13,500 miles. I politely declined and stated that I order my service ala carte, per the specific services spelled out in the manual. I didn't bother to ask what type of crap was in the $399 15K service.


S.

[HummBebe]

Thanks guys (BABHUMV and UNO), I'll call in the am and check in with the service dept.

Ed, well......yeah, thanks http://www.elcova.com/infopop/emoticons/icon_rolleyes.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

[DTHVLY]

It's probably axle wrap, its a frequent problem on trucks with leaf sprung rear ends. It's caused by the axle wrapping up on the rear springs and then kicking out while decelerating or accelerating. It is a clunk feeling and at first I thought it was the transmission also. It was a problem on my old Toy.
It can be fixed or reduced by getting stiffer springs or traction bars.

http://www.4x4wire.com/jeep/tech/susp/axlewrap/

[HummBebe]

Damm....that sounds serious. http://www.elcova.com/infopop/emoticons/icon_mad.gif

[evldave]

I'd bet you my hummer it isn't axle wrap.

That's common on USED vehicles, with softer springs, and I honestly can't remember ever hearing of it on a axle-over-spring setup. I've got some experience lifting Jeeps and axle-wrap happens over time, mostly with cheapo budget lifts using lift blocks on stock springs after tens (or hundreds) of thousands of miles.

The reason is that lift blocks move the center line of torque (the axle) farther away from the springs, which puts much more torque at the point of contact on the springs (usually an area of 2x4" - the block). Over time, weakness builds at that point, and the springs start to S-coil. The taller the block, the sooner you will get axle wrap. The H3 setup (axle-over-spring) is significantly more stable related to this since the axle torque is inside the radius of the spring, not outside like SOA.

The best and cheapest way to get rid of axle wrap is an add-a-leaf. It will make your ride stiff as hell, but your axle won't wrap. Given the stiffness of the ride, I seriously doubt that anyone has enough (hard) miles on their rear springs to cause the # of issues that seem to be outlined on this thread. I'd even be willing to bet we could disconnect the rear swaybar and drive with no problems (I think there's another thread on that) - trust me, if you can disconnect the swaybar and drive around a corner, your springs are stiff enough to not have axle wrap as a problem.

Why do I (think I) know so much about this? Because my last off-road rig was a Cherokee and I spent the last year fuggin around trying to resolve a driveline/transfer case problem. It kept binding the driveline and trashing u-joints and one output shaft on the TCase. Well, my 5 year-old 120k mile 4" lift rear springs had pretty much failed and I was getting axle wrap. After spending all my time trying to diagnose the problem, I went out and bought some RE 3.5" springs, took out the rear swaybar and was a happy camper (and bought my H3 2 months later). The axle wrap as so bad, the pinion was pivoting up through centerline of the driveshaft at WOT in 1st gear, and then jamming when I went off throttle and it pivoted back down.

[Steve - SanJose]

Originally posted by HummBebe:
Damm....that sounds serious. http://www.elcova.com/infopop/emoticons/icon_mad.gif

Yea I don't think my H3 can generate enough torque for something that serious.

http://www.elcova.com/infopop/emoticons/icon_eek.gif
S.

[HummBebe]

Originally posted by DTHVLY:
It's probably axle wrap, its a frequent problem on trucks with leaf sprung rear ends. It's caused by the axle wrapping up on the rear springs and then kicking out while decelerating or accelerating. It is a clunk feeling and at first I thought it was the transmission also. It was a problem on my old Toy.
It can be fixed or reduced by getting stiffer springs or traction bars.

http://www.4x4wire.com/jeep/tech/susp/axlewrap/

I was just in furnace creek....... http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

[HummBebe]

Originally posted by evldave:
I'd bet you my hummer it isn't axle wrap.

That's common on USED vehicles, with softer springs, and I honestly can't remember ever hearing of it on a axle-over-spring setup. I've got some experience lifting Jeeps and axle-wrap happens over time, mostly with cheapo budget lifts using lift blocks on stock springs after tens (or hundreds) of thousands of miles.

The reason is that lift blocks move the center line of torque (the axle) farther away from the springs, which puts much more torque at the point of contact on the springs (usually an area of 2x4" - the block). Over time, weakness builds at that point, and the springs start to S-coil. The taller the block, the sooner you will get axle wrap. The H3 setup (axle-over-spring) is significantly more stable related to this since the axle torque is inside the radius of the spring, not outside like SOA.

The best and cheapest way to get rid of axle wrap is an add-a-leaf. It will make your ride stiff as hell, but your axle won't wrap. Given the stiffness of the ride, I seriously doubt that anyone has enough (hard) miles on their rear springs to cause the # of issues that seem to be outlined on this thread. I'd even be willing to bet we could disconnect the rear swaybar and drive with no problems (I think there's another thread on that) - trust me, if you can disconnect the swaybar and drive around a corner, your springs are stiff enough to not have axle wrap as a problem.

Why do I (think I) know so much about this? Because my last off-road rig was a Cherokee and I spent the last year fuggin around trying to resolve a driveline/transfer case problem. It kept binding the driveline and trashing u-joints and one output shaft on the TCase. Well, my 5 year-old 120k mile 4" lift rear springs had pretty much failed and I was getting axle wrap. After spending all my time trying to diagnose the problem, I went out and bought some RE 3.5" springs, took out the rear swaybar and was a happy camper (and bought my H3 2 months later). The axle wrap as so bad, the pinion was pivoting up through centerline of the driveshaft at WOT in 1st gear, and then jamming when I went off throttle and it pivoted back down.

Ok evil, say I believe you (and I do), what do you think it is????

[evldave]

Honestly, I don't have a reasonable idea (and so I don't spout off in the forums). Since I'm in a wordy mood today, I'll continue...

If I were to conjecture (only because you lived up here and you asked) http://www.elcova.com/infopop/emoticons/icon_smile.gif - I'd follow the same thing I always do when diagnosing - start with the cheapest stuff first.

You wheel hard, put a lot of stress on the driveline. Check the u-joint. Reach down, try and move it perpendicular to the joints. Does it move left right (not rotationally)? If so, spend the $30 and have the u-joint R&R'd - or take it in for warranty service. Get a Spicer (sp?).

Does the driveline rotate and have some play in and out? There should be some movement in the parallel direction and rotated (not much, but a little). If none, there's binding somewhere. It could a number of things, but it's under warranty and tell the service tech.

Do you have an older rear end? http://www.elcova.com/infopop/emoticons/icon_wink.gif If so, there was a gear lube issue with the supplier and that may have caused an issue w/the gears in the rearend, but not enough to blow it up. Since this seems to have happened when you had the service done, putting new fluids may have made it easier to feel. Might want to look up mfr date and see if it was back w/that lot of parts.

In my completely uneducated guess, I'd say the torque converter isn't unlocking quickly and so the drivetrain is under locked load when you are stepping on the gas. I don't know all this fancy computerized stuff, but a torque converter is supposed to let the engine 'throttle up' without having the drivetrain acccelerate at the same rate (it's essentially slipping to let the motor spool up without spinning the tires at the same time - it builds power faster so you can put more oomph to the wheels when it finally does engage).

There is lost efficiency in this design because of the slipping, but it's required in automatic transmissions (otherwise the engine would stall when the rear wheels stop). Most modern transmissions have a 'lockup' converter that locks in either 3 or D to maximize the power transmission between the motor and...well...the transmission. When decelerating, the converter usually locks to help with slowing (you can feel this on a lot of vehicles) - when you accelerate, it should immediately unlock and slip a little.

On the H3, the converter locks when driving normally in D. When you step on the gas on the highway, it actually unlocks (check your RPM, they will increase quite a bit but it won't actually downshift - that's the converter unlocking and hitting it's stall speed). IF (big if) it doesn't unlock and you put too much gas on, it can bog down - the equivalent of being in 5th gear in a stick driving at slow speeds. This can cause all kinds of wierd clunking and bogging.

On my H3, I noticed when I first got it that it had a significant amount of slip at lower speed - to the point of annoyance that I couldn't use engine compression to keep the rig slow on downhills. As I've now got 8k miles on it, I've noticed the converter locks up much sooner and better at low speed - it may be a design or trait of the H3 - the older the tranny, the more it locks up? I don't know, but it's noticeable to me because I've been paying attention to it.

Is this an issue? I have no idea, but I wouldn't worry about it. I'd go beat the hell out of it right now to see if it breaks - if it does, going to MOAB is a bad idea, if it doesn't, don't worry about it.

I'm sure other more edumicated people will fix any of my factually inaccurate statements - a lot of that going on lately...

And a note on axle wrap - it happens on all rigs and is expected to a small degree, however EXCESS axle wrap (that would cause this sort of problem) should only be present on older springs.

[HummBebe]

Evil, thanks, you seem to have a good logic going on here.....you know your beer too http://www.elcova.com/infopop/emoticons/icon_biggrin.gif http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

I appreciate you taking the time. Kiss kiss. http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

[DTHVLY]

Originally posted by evldave:
I'd bet you my hummer it isn't axle wrap.

That's common on USED vehicles, with softer springs, and I honestly can't remember ever hearing of it on a axle-over-spring setup. I've got some experience lifting Jeeps and axle-wrap happens over time, mostly with cheapo budget lifts using lift blocks on stock springs after tens (or hundreds) of thousands of miles.

The best and cheapest way to get rid of axle wrap is an add-a-leaf. It will make your ride stiff as hell, but your axle won't wrap. Given the stiffness of the ride, I seriously doubt that anyone has enough (hard) miles on their rear springs to cause the # of issues that seem to be outlined on this thread. I'd even be willing to bet we could disconnect the rear swaybar and drive with no problems (I think there's another thread on that) - trust me, if you can disconnect the swaybar and drive around a corner, your springs are stiff enough to not have axle wrap as a problem.

While axle wrap is more likely with old springs it does occur on new vehicles. Ask anyone with a Tacoma they come straight from the factory with it bad and they only have 190hp. After driving a Tacoma I swore I would never buy a leaf spung offroad rig. I really like the Toy 4 link coilover rear suspensions a lot better than the leafs, that's one of the main reasons I want't to check out the FJ.

While it's less likely on a axle-over-spring setup it does still happen but the swaybar disconnect would be a good test.

Don't you think a traction bar would be a better cure because it dousn't stiffen the ride like an AAL and won't soften like the AAL eventually will.

Is your name "evldave" taken from Evil Dave on the Stern show?

[evldave]

evldave was a nickname I got in college for being a dick. Now that I'm older and wiser, I'm just a more experienced dick.

That said, I agree traction bars are much better for traction control (that's why they are used on drag cars) but their cost and setup can be tricky (and are usually more $$ than an AAL).

Interesting to hear about Tacoma's, just goes to show we don't always know everything. I'm familiar w/the axle-over-spring Comanchees and they never had (new) spring axle wrap issues.

I'm still curious as to the resolution on this - I wonder if it's one of those 'annoyance' things or if it's going to be something that is a real issue...

[Steve - SanJose]

yea but at least now we understand the origin of "evildick" or whatever the name is... http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

S.

[evldave]

oh, man, that's cold http://www.elcova.com/infopop/emoticons/icon_mad.gif

If I cared what you thought, I'd be hurt http://www.elcova.com/infopop/emoticons/icon_wink.gif

[Steve - SanJose]

I must of mispelled evldave. Sorry http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

That's why I have to wear those big bullit-proof sunglasses.

S.

[wannabeH3]

mine had it and now they are replacing my transfer case

[Edspad]

Originally posted by wannabeH3:
mine had it and now they are replacing my transfer case
Dont Cry HummBebe, its going to be ok...really!!

[HummBebe]

I just might.... http://www.elcova.com/infopop/emoticons/icon_frown.gif

[HummBebe]

Aside frrom the advice of a few of my buds, can F5fstop, or Chevyhighperformance weigh in on this subject?
Prease http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

[ChevyHighPerformance]

Originally posted by HummBebe:
Aside frrom the advice of a few of my buds, can F5fstop, or Chevyhighperformance weigh in on this subject?
Prease http://www.elcova.com/infopop/emoticons/icon_biggrin.gif

I've been reading this thread off and on. I'm not sure I understand all of the conditions when you feel the jerk (i.e., throttle position, brake pressure (if any), how long you were decelerating, how fast you let off the throttle (there is a throttle fast decay fuel shut off), does the jerk feel like it is accelerating or decelerating the H3, etc. If you shift to 3rd (or neutral) and decelerate, do you still feel the jerk? If the H3 is parked in neutral with the parking brake on, can you rotate the front and rear driveshafts more than a few degrees - do you hear a clank which may indicate too much ring/pinion slop? Could it be the fly-by-wire throttle body? Not sure - I changed the inlet and out air flow through mine to have a more laminar flow and may have fixed an unknown problem???

For example, here is a stock Silverado SS's torque converter lock/unlock tables for cruise mode (the H3's will be different but similar structure). The top row shows throttle position from 0% to 100%. The left column shows what speed the TTC is applied per gear and what speed is the TTC is release per gear. For fourth gear, the speeds vary some for low throttle positions. This would make sense if you are at highway speeds (4th gear) and slow down. If you lightly accelerate just after the TCC unlocks it may try to relock very soon which will cause a slight jerk. You can see that the TCC never locks in 2nd gear. I'm not saying this is what you feel - this was just meant to be an example of the complexity of the tranny operating parameters. There are similar tables for line pressure, shift speed, etc.

[HummBebe]

In decellerating from 65 mph or more,(letting my foot off the gas to slow down) when you begin to accellerate (put pressure on the accellerator pedal), there is a deep sounding (like when you forget to downshift and try to take off....lugging the engine) clunk/jerk before it will shift down to accellerate.Usually around 2000 RPM's.

I will do it while in 4th and in 3rd. It does not do it in 2nd or 1st.