Rear Differential Fluid

[snfgw]

This is my first post since i bought my fsj, i got a 1986 GW, and have been replacing the u-joints on it. I notice my differential fluid is low on the rear, but i dont know if i have limited slip differential or not, so i cant figure out which weight to use. also the differential is not marked as far as i can see with any particulars for it. Any replies would be helpful.

Thanks,
Stephen

[Veepster]

wa a limited slip offered on the FSJ??

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Peace.............BartG

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[Stuka]

Yes, it was called a "trac-lock" if i remeber right. Was available in several years. Pulling the cover you can pretty easily tell if its a open dif or a lsd. And the LSD didnt last long, they wore out really quick. (25k miles or so)

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<UL TYPE=SQUARE>
1975 Cherokee
360 w/ Edelbrock Performer Intake and Carb
T18a
Spicer 20 T-Case
Dana44 w/3.54 Gears
[/list]

[trssho]

If you raise the vehicle on a hoist, put the trans in neutral, and spin one of the rear tires. If they spin in the same direction, you have limited slip. If the tires spin in opposite directions, you have an open diff. Most likely it is not, but if it is, you will need to add special fluid.

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[MindiR]

Correct me if I'm wrong, but I think you can use limited slip fluid in either.

[Brazzy]

If you do have the ltd slip you will need to use Amzoil or some other synthetic with the modifier. This is recomended in the owners manual and the Haynes manual. Ltd slip came with the tow package!
Course if your not towin, don't know if it matters.

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Brazzy
Formerly abused 87 G.W. 175k
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[snfgw]

Thanks for all the replies, it did come with an amc factory tow package, but i have yet to tow anything with it. i dont think that it is limited slip so thats good.
Thanks again for the help

Stephen

[BobBarry]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Brazzy:
If you do have the ltd slip you will need to use Amzoil or some other synthetic with the modifier. This is recomended in the owners manual and the Haynes manual. Ltd slip came with the tow package!<HR></BLOCKQUOTE>

The ltd slip didn't come with ALL trailering packages (I've got an '88 GW to prove it).

But as noted, the additive can be used in non-LSD applications as well. Or, you could put in the regular lube, and add the posi stuff if it chatters.

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Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/

[Snakeyes_Tx]

Okay, being its an 86, it has an AMC20 rear.

There isn't markings, but there is a Casting on the topside of the differential "leg" on the driver's side. (I refer to the "leg" as the area that the axle tubes connect to)

If it has CC stamped on it, you have a 3.31 open differential, if it just C I think that is the 3.31 Track Lock

If you have a tow package, it'll be limited slip, BUT that doesn't mean if its still good or not.

*** The wheels will *not* turn in the same direction if you have a limited slip ***

Spools and lockers that are engaged will spin together in the same direction. Even a locker has to be "Racheted" and locked before they spin together. There has to be torque against it to let it engage. Track locks are a "Torque-slip" function. Not a free spinning one. I know for a fact that my track-lock works *very* well on my Dana 60 and the wheels spin in opposite directions on a lift.

You can feel some resistance if you and a friend turn the rear wheels together in the same direction. That is a good way to determine.

Also, just use 80W90 gear oil with a limited slip additive (in a separate bottle.. I don't trust pre-mixed). You can't go wrong with that.


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Snakeyes_Tx
86 J-20 "The Rusty Dinosaur"
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[This message has been edited by Snakeyes_Tx (edited June 13, 2001).]