1985 Model 20 Gear Ratios

[Tad]

OK, so what was offered?
It looks to have a tow package, big reciever hitch and external tranny cooler.
Tried spinning the wheel and counting the yoke revolutions but not sure I did it right.
Only spun it once (should have read up on this more) and it appeard to turn about 1.6 or 1.7 revolutions.
Going to be putting this in the 1970 and would be nice to figure it out before I drag it home.
I'm not in a position to pull the cover and count teeth right now.

[kyjman]

Hey Tas,

According to my 4X4 standard the axles were this in 1985:

J-10 2.73 with 4 speed manual
3.31 with auto

J-20 3.73

[mark32725]

I have a 84 Wag with all the stuff you mentioned and I have a 3.31 ratio...

[ November 29, 2002, 09:59 AM: Message edited by: mark32725 ]

[talntar]

i have a 85 with 2.73s.i think that the 2.73 are more common.heard that the 3.31 were an option

[mark32725]

Originally posted by talntar:
i have a 85 with 2.73s.i think that the 2.73 are more common.heard that the 3.31 were an optionDo you have the towing package? AKA the hitch and the external tranny cooler?

[talntar]

yes i do

[talntar]

iirc it also has to do with weather you got tow "a" or "b" package

[joe]

Tad, the only two ratios avail in any 80 up Wag/Chero were std 2.73's and the optional 3.31's which also came stock with the B(5000lb) tow pack. When you do the spin the tire once and count driveshaft revs thing you need to multiply the shaft revs by two or spin the tire twice. Sounds like you have the 3.31's. Easy way to tell is look at the flat boss next to the dowel hole on the right/outside side of the diff casting. The axle ratio code is stampped there on the M20's. 3.31's will be code "B", 3.31's w/trac-loc will be "BB", 2.73's will be "D" and 2.73's w/trac-loc will be "DD".

[Tad]

kyjman, mark32725, talntar... thanks for te help guys I appreciate it very much.
-joe, I always read up before I ask questions and read your write up at...
-joe Axle ID (http://www.ifsja.org/tech/axle/axleid.shtml)
...this morning before I drove up to look this morning.
Unfortunatly the rig is sitting on blocks, not one of my favorite places to be doing any heavy cleaning.
I appreciate your write ups in the Technical Library very much.
I am going to conclude it has the 331's which is what I have now and works great with my plans to upgrade to the newer 6 lug axles prior to Ouray next July.
Thank you all very much.
:cool:

[derf]

My waggy came with 3.31's stock. I just had 3.73's installed today. Since I had the 3.31's, I didn't have to replace either carrier.

The rear AMC20 with 2.73's has a different carrier than if you had 3.09's through 4.88's.

The front Dana44 has two carriers as well. One for gears 3.73 and lower and one for 3.93's and above.