72 cj5 axle ratio

[beat cj]

I have a 72 Cj5 that i have been reassembling for almost a year now. I finally got it running and drove it. It was ungodly high geared. So i jacked up the rear of the jeep and marked the driveshaft to count rotations....My brother turned the wheel a revolution and i counted the shaft rotation. I only came up with about 1.8 turns. This is way low, i never even saw a ring and pinion set this low( numerically). Has anybody heard of a ratio used < 2:1 in the axle?? Any info would help. thanks

[4x401cj]

Pull the rear cover and read the #`s on the ring gear. Most of the `72-`75 cj`s I`ve delt with had 3.73`s. That would be my guess for yours also.

[beat cj]

yes thats my next step...i am at college and i only get home once in a while so next time i will do that.

[Haggar]

If you only turned one wheel, and the other stayed put, it rotates the driveshaft only 1/2 the number of times.


3.73 gears / 2 = 1.865..

Most of the 72-75 Bastard years had 3.73 gears, some of the 6 cyls had 4.27s. Those were the only gears available.

Both my 75s had 3.73s, one was a 304, one was a 232.

[piratebuggy]

Sometimes it's easier to rotate the wheel 10 times to get a better read on the exact ratio.

[Chato]

Originally Posted by piratebuggy

Sometimes it's easier to rotate the wheel 10 times to get a better read on the exact ratio.

Add 4.10s to that

[pharmvet]

Haggar, please tell me more about how only turning 1 wheel rotates the drive shaft 1/2 #times. I guess I dont fully understand how differential / drive shaft works. thanks.

[beat cj]

hmm your explanation solves the problem 1.8 mystery but I never heard of the driveshaft rotating half as much by only turning one wheel....interesting

[KiGrind]

HERE!

http://www.off-road.com/jeep/tech/axle/amc20.html

This page covers all the axels in Jeeps and gives ratios and how to ID them and such.

Helped me!! Turns out I've got an AMC20 3.54 Trak-Lok (Wasn't planningon a locker anyways :-/ not in this weak poo)

[piratebuggy]

Of course if you have a limited slip you wouldn't be able to rotate just one wheel.My axle code comes up as a 3.54 Trak-Lok but it can turn one wheel,I was told somebody "went through" the rear axle before I bought it.My question is-to save me having to pull the cover off-is the Trak-Lok a clutch type or torque sensing type of limited slip?(anyone?)The driveshaft only turns half times do to the differential action of the spider gears in an open type diff.

[KiGrind]

Originally Posted by piratebuggy

Of course if you have a limited slip you wouldn't be able to rotate just one wheel.My axle code comes up as a 3.54 Trak-Lok but it can turn one wheel,I was told somebody "went through" the rear axle before I bought it.My question is-to save me having to pull the cover off-is the Trak-Lok a clutch type or torque sensing type of limited slip?(anyone?)The driveshaft only turns half times do to the differential action of the spider gears in an open type diff.

I think its clutch and mine does the same thing, was told they might need replacing.

I'll do it when I replace the bearings and seals.. What a fun project that will be for me.