Crawl Ratio??
 

I did a search and didnt find any results. Does anyone know the crawl ratio for a manual transmission with off-road package? Iv never needed to
be in 1st gear and 4 low at the sametime. Anyone know that ratio?

Re: Crawl Ratio??
 

Manual 69:1, auto 56:1:D


ooops sorry forgot to post my source

http://www.hummer3.net/specs.html

Re: Crawl Ratio??
 

Not sure how accurate that is. Its from 2004 and they still list the two different rear axle ratios. :rolleyes: ;)

From Hummer's site:

CRAWL RATIO:

BASE VEHICLE: 45.0:1
WITH OPTIONAL OFF-ROAD SUSPENSION PACKAGE: 68.9:1

No mention of man v. auto. :confused:

http://www.hummer.com/popups/h3/h3_full_specs.pdf

Re: Crawl Ratio??
 

Sounds like you need to come out with us again. ;) :D

Re: Crawl Ratio??
 

Sounds right to me, can't remember the auto, but know it is in the mid to high 50s, so I would say you have it correct.

Re: Crawl Ratio??
 

H3 came out in 2006, what they listed in 2004 is innacurate. The H3 uses only one gear ratio for any model in 2006 and that is 4.56:1.

Re: Crawl Ratio??
 

Look at the H3 Brochure from the dealer.

It has both the auto and manual ratios. Sorry my book is at home.

Re: Crawl Ratio??
 

You also need to factor in the torque multiplication of an auto, usually giving a 4x at the lowest revs needed for rock - crawling.

This will equate to closer to 200:1 for an auto transmission (and you won't need three feet while rock crawling).

-C

Re: Crawl Ratio??
 

that's just stupid.

You are suggesting the automatic transmission quadruples the torque over a standard transmission?

Re: Crawl Ratio??
 

LOL - I thought I was stupid or uneducated. Please explain how (if true)

Re: Crawl Ratio??
 

This has been discussed a few other times, and sorry to tell you, the brochure from the dealer is incorrect. (That's why it has a little disclaimer on the bottom talking about errors.) :D
I have personally checked with the axle engineer in charge of the H3 (quite a few times on other subjects too:eek: ), the brand quality chassis manager has been in our facility quite a few times, and the service engineer for this part is a close friend...it is a 4.56:1 ratio in the Diffs.

(Trans 1st gear ratio x transfer case ratio x axle ratio = crawl ratio)

AUTO
Off-Road:3.059 x 4 x 4.56 = 55.796 (rounded to 56:1)
Non-Off-Road: 3.059 x 2.64 x 4.56 = 36.825 (rounded 37:1)

MANUAL
Off-Road: 3.78 x 4 x 4.56 = 68.947 (rounded 69:1)
Non-Off-Road: 3.78 x 2.64 x 4.56 = 45.505 (rounded 46:1)

NOTE: The manual first gear might be 3.79, I came across two specs in my PAD drawings for this gear.

Re: Crawl Ratio??
 

HA!!!:D

No correction for Bebe this time:D :D :D :D

Re: Crawl Ratio??
 

You got lucky. :p :D

Re: Crawl Ratio??
 

Thanks for the info F5. It would have been nice if Hummer posted both the manual and auto specs on their site. But I guess that's marketing for you. :rolleyes:

Re: Crawl Ratio??
 

The torque converter has a multiplier value depending on RPM, but 4x seems high. I have seen numbers between 1.5 and 2 for some auto trannies.

For example, the H1 torque converter ratio is 2.2:1, according to this link http://www.kellyhummer.com/h1.htm

Re: Crawl Ratio??
 

Ok, so.......

Re: Crawl Ratio??
 

Does anyone know the multiplier value of the H3's 4L60e? I'm curious about the torque multiplier curve too ... at what RPMs do you get the most out the converter?

Re: Crawl Ratio??
 

wouldn't a better question be "when does stall occur and lockup occur?"

Re: Crawl Ratio??
 

Every equation I have ever seen for a crawl ratio has never taken into account the torque converter. Reason is it is next to impossible since the converter slips at a different rate at different engine rpms. Therefore, the calculation would be next to impossible. You would have to figure out all the different rpms you would have in a given range.
All crawl ratios are figured without the torque converter taken into account by any manufacturer I have ever seen.
I have seen calculations for the H1, but it also takes into account the wheel multipliers too.

Re: Crawl Ratio??
 

Thanks f5fstop ... I appreciate the info.

Re: Crawl Ratio??
 

69:1 sounds like a great ratio. How does that compare to brands such as Jeeps and Toyotas??

Re: Crawl Ratio??
 

as flywheel RPMs increase the torque converter is less and less efficient. The torque multiplication only occurs during a small RPM range on most small trucks due to many reasons. With electronics controlling lockup, along with the inefficiency of the converter itself, it's moot to consider it a factor for crawl ratio.

If one could effectively figure out the actual RPM range to hold the vehicle at and the electronics wasn't controlling the converter, you would burn the converter up and overheat the transmission.

Re: Crawl Ratio??
 

Crawl ratio with an automatic is just about meaningless anyway, with the torque converter disconnecting the driveline from the engine. Unless you like to launch off the top of rocks, and test your brake reflex skills, get a manual, with which the H3 has an exemplary crawl ratio.

Michael

Re: Crawl Ratio??
 

I will never have a manual, again, for off-roading. Too many times you have to ride the clutch to get out of sand, over rocks, etc., and if you have to stop going uphill, an auto makes it a lot easier.:D
When riding over a boulder with a manual, you have the same problem at a very low speed, you ride the clutch, then have to test your brake reflex skills just like an auto.

Re: Crawl Ratio??
 

agreed

besides, crawl ratio is something web wheelers get all warm and fuzzy about

Re: Crawl Ratio??
 

Same here! I regret getting a manual transmission for four wheeling. My last truck was an auto and was a lot better!!

Re: Crawl Ratio??
 

No no no. Don't fret. I rode along with " 4-lo" (I dunno if that is his name here or not) in Tellico. He had a Yota pick-up manual and it was sweet.

There are a lot of things you can do with it that help you tailor the tranny. It really crawls in 1st. He taught me some moves with his shifter (;)) when turning and maneuvering around, it was a lot of work but pretty darn cool.

There are manual techniques that are to your advantage. You just have to stay off the clutch. Plus they are easier to fix etc. Maybe you could check it out or pm him and ask.

Re: Crawl Ratio??
 

I prefer an auto for offroad :D jmtcw;)

Re: Crawl Ratio??
 

Auto, good enough for H1 and H2 good enough for me and my three

Re: Crawl Ratio??
 

Ken had a fun and wild ride across the creek with him at the bottom of #5 on Sunday night too :eek: :cool:

Re: Crawl Ratio??
 

It's best in class for 2006 models, but the 2006 JK Rubicon Ultd will beat it next year. The source I used for this graph supplied different numbers than the ones in this thread. I'll update them when I get a chance.

Re: Crawl Ratio??
 

In the Automatic, the H3 will have best in class crawl ratio bar none. (Here are some updated graphs ... easier to read.

Re: Crawl Ratio??
 

Wisha, can you do a power to weight ratio comparison??

Re: Crawl Ratio??
 

I think offroad driving techniques really aren't that different for automatics vs. manuals. Brake-throttle-modulation techniques used for wheeling automatic transmissions are comparable to feathering the clutch in manuals. There are times I love the control of a manual (usually offroad), and times I wish I had an automatic (like when I go to pay a parking garage attendent located on a steep grade and some A-hole pulls up 2 inches behind me).

Re: Crawl Ratio??
 

Have you tried an H3 rock crawling with the 4:1 transfer case and adventure package? With a 68 to 1 crawl ratio, how much riding of the clutch do you need to do? That thing barely moves. That thing eats rocks for lunch with the clutch fully engaged. No slipping requred.:D

Michael

Re: Crawl Ratio??
 

Sure, but imho you have to factor in the gearing to get the whole picture. Here ya go.

Re: Crawl Ratio??
 

Here's a chart for Geared Crawl HP to Weight ratio

Re: Crawl Ratio??
 

I heart teh neeeerds:D :D

Re: Crawl Ratio??
 

Here's a look at the Geared Torque - Weight ratio

Re: Crawl Ratio??
 

THAT"S more like it!!!