Lurching 40 to 50 mph slight hill
 

Recently my H3 AT with 7700 miles has started to lurch climbing slight hills at 40 to 50 mph. Dropping it into third gear does not make it go away nor changing to premium gas. I have also added three bottles of Techron from Chevron. Still no change.

Anyone else experiencing this?

Re: Lurching 40 to 50 mph slight hill
 

Never experienced this in 17K miles so far.

S.

Re: Lurching 40 to 50 mph slight hill
 

How's the idle? Is the engine light on?
Does it only happen when going up a hill?
Sounds like the torque converter clutch to me, which is engaged in 4th and 3rd gear, is going between locked and unlocked.
Could be an engine miss, but three cans of Techron won't help if it is. Techron is good for keeping the engine and injector clean, as well as the fuel sending unit (if using the right Techron).
Can't help much with a long distance diagnosis, suggest a dealer visit.

Re: Lurching 40 to 50 mph slight hill
 

Since it doesn't go away when I drop into 3rd gear, I figure it can't be the AT torque converter locking/unlocking.
No check engine light.
No idle problem.

How does the center dif work? Engine compression problem? But then why only uphill?

Yep, visit to dealer is called for, but I expect they will say "Problem not found".

Can leases be ended due to fundamental flaws such as this if it can't be repaired - i.e. GM says it is normal?

Re: Lurching 40 to 50 mph slight hill
 

Your third gear theory is wrong, 4L transmissions will lock in manual 3rd gear, as well as in overdrive 4th gear.
Possibly an engine compression problem, but if it is the cylinder head issue, it would cause a rough idle, and the PCM would pick up a misfire after certain counts and turn on the idiot light.
As for buy backs, is this your first problem? Call your lease company. But if it natural, it is between your lease company and GM.

I really don't know of any heavy vehicle with an automatic and limited HP that will not do some shifting around on mountain roads. But then again, I don't know if it is a shifting problem or a TCC problem, or something entirely different. Good luck.

Re: Lurching 40 to 50 mph slight hill
 

Interesting. I did not realize that the H3's AT would torque lock in 3rd gear. My other cars only did it in top gear.

But I now believe you are right about the torque converter lockup being the problem. Today I kept the speed going uphill below the 40 mph where it locks up and sure enough there was no lurching.

Lease is with GM and it is the first shop visit - but not where I bought it.

Shifting is no problem with the transmission. I expect it to with the H3's weight/power ratio. Seemed fine until lately.

Still surprised that putting on the brakes doesn't release the lockup. My '01 Camaro did and it made it much more drivable.

Re: Lurching 40 to 50 mph slight hill
 

So the dealer said the lurching/lugging was present in their three loaner H3's also and therefore is considered normal. And since the COMPUTER could find nothing (even though the tech felt the shuddering), it was obviously OK per GM warranty process - what ever happened to good old fashioned seat of the pants repair?

So it is becoming more and more noticeable, and I now dread driving my H3 vs the joy I had for the first 5000 miles.

And unfortunately I still have 31 months to go on my lease.

I guess I will try the GM appeal process, but eventually will most likely have to look into buying my H3 out of the lease and selling it for a huge loss.

I knew I should have bought a GX470. Never have problems with Toyota/Lexus, but I wanted to be patriotic and buy American. Boy what a sucker I was.....

Re: Lurching 40 to 50 mph slight hill
 

Re: Lurching 40 to 50 mph slight hill
 

Warranty is useless when the local dealer says "it is normal".

Re: Lurching 40 to 50 mph slight hill
 

Is there another dealer around you can go to? Just because they don't want to do anything doesn't mean it can't or won't be fixed by another dealer. As far as should have bought the Lexus, go for it. It doesn't matter what type of vehicle it is, there will be people that have problems. I have known people who have bought a Lexus and had more problems than I have had with all the GM vehicles I have owned combined.

Re: Lurching 40 to 50 mph slight hill
 

Drivetrain shuddering problem has worsened in last 1000 miles. Now happens pretty much full time. Feels like miss in engine plus unbalanced tires. After two tries, determined to be "normal".

My present guess is that it is the transfer case since it happens even when the transmission is in neutral.

I am surprised no one else is noticing this since according to the dealership all three of their loaners have the same shuddering.

By the way, lemon laws appear to be somewhat useless in that if it can't be repaired in X times (usually 3 or 4 tries), then the car must be bought back...but what happens when manufacturer says defect is "normal" after 2 repair attempts? A loop hole that needs to be corrected.

Re: Lurching 40 to 50 mph slight hill
 

Find another dealer, that is not normal. As for the dealer's statment, do you believe a dealer who won't repair your vehicle? If a dealers cannot find the problem, they love to say it happens on all H3s. Then you go to a forum and find out it is not normal. Odds are the dealer is full of s**t.
Personally, with your miles and my guess at when you purchased the vehicle, I would go after the rear diff.
If you had the cylinder head problem, you should set a code for misfire. However, if your rear axle is going, it will give the same symptoms, especially the unbalanced tire feel. Early, prior to August of last year, some of the rear axles were produced with lapping compound left on the gears, and this destroyed the gear set.
If you have a legitimate problem, three trips to the dealer is as good as three attempts to repair the problem in most states.
I go back to my first statement...find another dealer.

Re: Lurching 40 to 50 mph slight hill
 

Actually, I have no complaints with the local dealer. They are trying to fix it and opened a case with GM corporate, but GM is the one that is saying it is normal after directing certain tests be run. The dealer must now wait for a GM representative to OK trying part replacements such as torque converter, transfer case, etc, or to request an engineer come observe the problem. Without GM's OK, nothing more will happen except arbitration.

Re: Lurching 40 to 50 mph slight hill
 

Did you drive any of the H3 loaners to see if they really felt the same?

S.

Re: Lurching 40 to 50 mph slight hill
 

Your dealer is weak, a call from the woner or GM can get things moving. Call Hummer customer service direct. You are too nice or your dealer is jerkin you. They did not build this many trucks to have this kind of problem. Did you won a truck before? The H3 is a truck and will react alot diffrent then fu fu unibodys. Make some noise and calls. Call who your lease is with. GMAC ? get some people working for you.

Re: Lurching 40 to 50 mph slight hill
 

I agree. MAKE SOME NOISE!!!
Don't forget to be grateful that you aren't over 1,000 miles from the nearest dealer!!! :eek:

Re: Lurching 40 to 50 mph slight hill
 

Now at 12000 miles and vehicle still jerks at slight throttle once the torque converter locks. It is in the shop now to be investigated. The loaner has the same problem, if not worse, with only 1200 miles on it.

I am surprised that no one else has this problem since it appears to be a generic design defect according to what I've been told and experienced.

Perhaps driving on flat or slightly inclined roads at 40-45 mph is not common?

Oh, and to those who doubt, even my wife who is not a car nut notices the problem now. Also, I have driven probably 100 rental cars and owned about 20, none of which have had this anomaly. My guess it is related to the full time 4wd and how the slip shafts are arranged with the transfer case which is free to rock back and forth. Does anyone know of a shock absorber for the transfer case?

Re: Lurching 40 to 50 mph slight hill
 

I had something like this in a 95 Blazer I owned. Turned out to be the throttle postiion sensor.
I finally figure it out by downshifting od flat land so the throttle was in the same position as going up hill. At that throttle point it would stumble or lurch depending how you look at it.

Re: Lurching 40 to 50 mph slight hill
 

i have a noticable surge too , but only when going down hill with cruise-control . it feels like slack in the 40-60 split in high range unlocked . feels like theres a load then no load , back and forth till hill flattens out . then seems as smooth as ever .

Re: Lurching 40 to 50 mph slight hill
 

Hey Dave,

I would love to try this out on my truck to see if I got the problem too, but I need some pretty exact info.

Can you tell me what you mean by a slight hill, about how many degrees. And again tell me at what speed I should drive. Also if there is anything else special that i should do. I wana do everything exact, is AC on, is Traction Control on or off, when climbing the slight hill at around how many rps is your ingine.

I live in chicago, not many hills around here, but if you get me this info so that i can repeat it, i am willing to go out to hoffman estates, about 20-30 miles out, theres some pretty nice hills out there.

Im one of those people that like to know if and when their vehicle has a problem even if it really doesnt effect them, thats why i wana check this out. Thanks!