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.