where to find auto transmission gear ratios - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > where to find auto transmission gear ratios

Rough Country Lift Kits and Parts!Ruffstuff Axle Simple Swap Kit!Don't forget the Jeep Forum discount, 10% off!

Reply
Unread 02-28-2008, 10:32 PM   #1
snakehunter
Registered User
2000 TJ Wrangler 
 
Join Date: May 2005
Location: Fresno, CA
Posts: 114
improving crawl ratio



Where can I find the gear ratios for my 2000 auto transmission and the transfer case low range?

I'm trying to understand how to calculate the crawl ratio

my understanding is craw ratio = transmission 1st gear ratio X transfer case low range X 4.56 (my axle ratio)



Thanks.

__________________
2000 Sahara RE 4.5, Alloy USA front Axles (D30) w/Aussie locker, Superior Super 35, 4.56 gears, OME Shocks, Centric Front Discs w/EBC Yellow pads, AtoZ Fab Rocker Guards,Goodyear MT/R 33x12.5x15 on 15x8 Rock Crawler 51's, other minor stuff... [B][COLOR=White]
/ | [____],
1---L-OlllllllO-
()_)()_)----)_) White Jeep Club Member #111[/COLOR][/B]

Last edited by snakehunter; 02-28-2008 at 11:22 PM..
snakehunter is offline   Reply With Quote
Unread 02-28-2008, 10:42 PM   #2
NakedJeeper
Registered User
1998 TJ Wrangler 
 
Join Date: Jul 2004
Location: Colorado Springs, CO
Posts: 599
Crawl Ratio Formula : Transmission Ration * Transfer Case Ratio * Axle Ration = Crawl Ratio

There are a bunch of gear ratio calculators on the net. Google is your friend.

http://www.nakedjeep.com/Knowledge/Math/njRatios.html
http://www.nakedjeep.com/Knowledge/M...ulators02.html
__________________
www.NakedJeep.com
NakedJeeper is offline   Reply With Quote
Unread 02-28-2008, 11:06 PM   #3
snakehunter
Registered User
2000 TJ Wrangler 
 
Join Date: May 2005
Location: Fresno, CA
Posts: 114
Quote:
Originally Posted by NakedJeeper View Post
Crawl Ratio Formula : Transmission Ration * Transfer Case Ratio * Axle Ration = Crawl Ratio

There are a bunch of gear ratio calculators on the net. Google is your friend.

http://www.nakedjeep.com/Knowledge/Math/njRatios.html
http://www.nakedjeep.com/Knowledge/M...ulators02.html
Did a google search for the calculation but didn't find out where I could find the actual gear ratios.... Thanks.

Now that I know them I'm not impressed.. I'm at about 28 without any changes (3.73 axle ratio) and only get to 50 regearing to 4.56 and adding a teralow.

Is there a way to get real low without the atlas?

It didn't seem to add that much going to 4.88 and it's my daily driver anyway.

Or, should I not pay attention to my toyota friends who boast of more than a 100 crawl ratio?
__________________
2000 Sahara RE 4.5, Alloy USA front Axles (D30) w/Aussie locker, Superior Super 35, 4.56 gears, OME Shocks, Centric Front Discs w/EBC Yellow pads, AtoZ Fab Rocker Guards,Goodyear MT/R 33x12.5x15 on 15x8 Rock Crawler 51's, other minor stuff... [B][COLOR=White]
/ | [____],
1---L-OlllllllO-
()_)()_)----)_) White Jeep Club Member #111[/COLOR][/B]
snakehunter is offline   Reply With Quote
Unread 02-29-2008, 06:27 AM   #4
Pillswoj
Registered User
1999 TJ Wrangler 
 
Join Date: Dec 2007
Location: Ontario, Canada
Posts: 2,765
Try here, there should be a listing for your Tranny.

http://www.grimmjeeper.com/gears.html

Regards,

Jeff
Pillswoj is offline   Reply With Quote
Unread 02-29-2008, 09:02 AM   #5
NakedJeeper
Registered User
1998 TJ Wrangler 
 
Join Date: Jul 2004
Location: Colorado Springs, CO
Posts: 599
There is a challenge getting a daily driver to crawl low and still hit freeway speeds. For a good balance you can get a Stak or TeraLow 4:1 or other transfer case option to get you a lower gear in 4-low - when you really need lower gears. That would not negatively affect freeway speed and power.

If you just lower the axle gears by going to 4:88s, then your lower at all speeds. You really need to gear the axles to match the tire size so you have good power in 2 wheel drive, too.

Just my humble opinion
__________________
www.NakedJeep.com
NakedJeeper is offline   Reply With Quote
Unread 02-29-2008, 09:05 AM   #6
jcssurf
Registered User
2004 LJ Wrangler 
 
Join Date: Sep 2007
Location: Richmond, VA
Posts: 694
You're forgetting that with your auto the torque converter pretty much add's a 3:1 gear ratio. So triple whatever you calculated.

But why do the numbers matter? Go by what feels right to you on the trail. I think with your 33's, 3speed, and 3.73's you have a perfect DD combo. But if you want a bit more offroad, do 4.10's.
__________________
2004 TJ-L with 3-4" of lift, 35's, and no money

The Unlimiteds shall inherit the earth.
jcssurf is offline   Reply With Quote
Unread 02-29-2008, 10:57 AM   #7
Wheelin98TJ
JEEP FREAK
 
Wheelin98TJ's Avatar
1998 TJ Wrangler 
 
Join Date: Apr 2004
Location: , Southeast MI
Posts: 23,690
Quote:
Originally Posted by jcssurf View Post
You're forgetting that with your auto the torque converter pretty much add's a 3:1 gear ratio. So triple whatever you calculated...
jcsurf is right on, you have forgotten about your torque converter.

You really cannot calculate an accurate crawl ratio. When your Yota buddies with manuals are bragging about crawl ratios in the 100's just tell them that your's is nearly infinite.

For future reference, the "Stock TJ Specifications" thread at the top of the forum has all of the ratios. Here's a link:

http://www.jeepforum.com/forum/f9/stock-tj-specifications-452871/
Wheelin98TJ is offline   Reply With Quote
Unread 02-29-2008, 04:11 PM   #8
snakehunter
Registered User
2000 TJ Wrangler 
 
Join Date: May 2005
Location: Fresno, CA
Posts: 114
Quote:
Originally Posted by Wheelin98TJ View Post
jcsurf is right on, you have forgotten about your torque converter.

You really cannot calculate an accurate crawl ratio. When your Yota buddies with manuals are bragging about crawl ratios in the 100's just tell them that your's is nearly infinite.

For future reference, the "Stock TJ Specifications" thread at the top of the forum has all of the ratios. Here's a link:

http://www.jeepforum.com/forum/showthread.php?t=452871


spent time studying how it works and adding the torque converter comment means I've got more to learn.

Why (sound like my kids) or how does it add to the ratio?

Why the comment about it being infinite? Can you explain that as well?

Or, just point me to someplace reliable to read something on the subject.

thanks for the input.
__________________
2000 Sahara RE 4.5, Alloy USA front Axles (D30) w/Aussie locker, Superior Super 35, 4.56 gears, OME Shocks, Centric Front Discs w/EBC Yellow pads, AtoZ Fab Rocker Guards,Goodyear MT/R 33x12.5x15 on 15x8 Rock Crawler 51's, other minor stuff... [B][COLOR=White]
/ | [____],
1---L-OlllllllO-
()_)()_)----)_) White Jeep Club Member #111[/COLOR][/B]
snakehunter is offline   Reply With Quote
Unread 03-01-2008, 06:19 AM   #9
Wheelin98TJ
JEEP FREAK
 
Wheelin98TJ's Avatar
1998 TJ Wrangler 
 
Join Date: Apr 2004
Location: , Southeast MI
Posts: 23,690
The reason your crawl ratio is nearly infinite is because of the torque multiplication effect the torque converter has.

Here's a pretty good link that explains how the torque converter works:

http://auto.howstuffworks.com/torque-converter.htm
Wheelin98TJ is offline   Reply With Quote
Unread 03-02-2008, 10:48 AM   #10
snakehunter
Registered User
2000 TJ Wrangler 
 
Join Date: May 2005
Location: Fresno, CA
Posts: 114
Quote:
Originally Posted by Wheelin98TJ View Post
The reason your crawl ratio is nearly infinite is because of the torque multiplication effect the torque converter has.

Here's a pretty good link that explains how the torque converter works:

http://auto.howstuffworks.com/torque-converter.htm
Thanks for the link - lots of good stuff....

Thanks everybody else as well...
__________________
2000 Sahara RE 4.5, Alloy USA front Axles (D30) w/Aussie locker, Superior Super 35, 4.56 gears, OME Shocks, Centric Front Discs w/EBC Yellow pads, AtoZ Fab Rocker Guards,Goodyear MT/R 33x12.5x15 on 15x8 Rock Crawler 51's, other minor stuff... [B][COLOR=White]
/ | [____],
1---L-OlllllllO-
()_)()_)----)_) White Jeep Club Member #111[/COLOR][/B]
snakehunter is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.