Crawl Ratio with auto Transmission - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on
Old 09-17-2010, 01:02 PM   #1
goldenfalcon's Avatar
Join Date: May 2009
Posts: 48
Crawl Ratio with auto Transmission

What is the Crawl Ratio with the automatic Transmission?

My axle Ratio = 3.73

It is true, Automatics can get away with a numerically lower crawl ratio? Why?


goldenfalcon is offline   Quote Quick Reply
Old 09-17-2010, 03:12 PM   #2
aelwero's Avatar
Join Date: Jul 2010
Location: Fort Bliss TX
Posts: 1,669
Images: 1
No clue on the ratio, but the getting away with a lower ratio is debatable, and I think it comes from the torque converter having a little "give" to it. (think stopping at a red light uphill... in an auto, on the right angle, you can let off the gas and just sit there... in a stick, "hovering" in the same manner without the brake would let the magic smoke out of your clutch.). I'm no expert, but that's the impression I get.

'71 DJ-5 (that isn't a typo)
'10 JKU Sport RHD

RHD... it's a jeep thing
aelwero is offline   Quote Quick Reply
Old 09-17-2010, 03:49 PM   #3
JIMBOX's Avatar
Join Date: Nov 2009
Posts: 9,914
My '08 JKU Rubi T-CASE (NV-241) OR Rock-Trac, has a crawl ratio of 73.1/1 all other jk's have 38.9/1

The Auto's are different in the Rubi with 4.10 axle ratio

When I'm in 4lo--there is "No Slippage" or give-

"ya gotta have class"
JIMBOX is offline   Quote Quick Reply
Old 09-17-2010, 04:17 PM   #4
Mabar's Avatar
Join Date: Jul 2010
Posts: 310
Originally Posted by goldenfalcon View Post
What is the Crawl Ratio with the automatic Transmission?

My axle Ratio = 3.73

It is true, Automatics can get away with a numerically lower crawl ratio? Why?

You can figure the crawl ratio for any vehicle by multiplying the lowest gear of your transmission x the axle ratio x the transfer case ratio.

Your auto trans 1st gear ratio is 2.84
Your transfer case ratio is 2.72
Your rear axle ratio is 3.73

Your crawl ratio is 28.81 (2.84 x 2.72 x 3.73)

An auto transmission has a lot of slip, so yes, even though your actual crawl ratio is 28.81, your effective crawl ratio really is lower because of the slip in the auto transmission.
The Bigger the Government, the Smaller the Citizen
Mabar is offline   Quote Quick Reply

Quick Reply

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
2004 Unlimited Auto Transmission Problem: Unlimited TJ Tech Forum 19 07-18-2014 09:31 AM
Resolution to Overheating Auto Transmission "HOT OIL" Warning catamountjk JK General Discussion Forum 74 06-16-2011 07:29 AM
Fellow Ohio Jeepers Help fick15 Ohio Jeep Forum 11 01-19-2010 10:56 PM
Jeep TJ auto transmission (42RLE) $500 / Texas cherokee980 Classifieds Archive 0 06-19-2009 07:45 AM
Walkin the Crawler 1372 to 1 crawl ratio stinger124 Off-Topic 10 12-14-2007 12:04 PM

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 11:38 PM.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC. is not in any way associated with the Chrysler Motors LLC