Im trying to determine if i have a Posi-Diff on my RamVan

May 25, 2005 10 Replies

The window sticker says :' Semi floating Rear 9 1/4 inch Heavy Duty Rear Axle'. Its on a 1997 Ram Maxi Van 3500.



Does this require the posi lube additive from Dodge ?



Thanks.



If it doesn't say, "Axle - Anti-spin differential" under the options section of the window sticker, then no, you don't have a limited slip, and you don't need the additive.

Semi-floating refers to the bearing configuration of the axles and IIRC all

9 1/4 rears are of a semi-floating design.

Check your rear diff there should be a tag on the bolts if so good bet it is anti-slip.

If it wont cause any harm, ill just go ahead and add some anyway just to be safe since im not sure if it is a Posi.

try using KY jelly, Dave..You said it works well on your neighbor's sheep

Simple check, jack up both rear wheels and place tranny in neutral. Spin a rear wheel and if other side spins in same direction it is a posi rear end. If it spins in opposite direction it is a open diff.

You can check it with just one wheel lifted as well. Lift one wheel and put it in neutral (be sure to block a front wheel) and try to turn the lifted wheel. If you can turn it, it is an open rear (or a dead limited slip) and if not, it is a posi.

Posi fluid has been used (and recommended by several manufacturers) to quiet noisy open diffs for several decades.

2 wheel check is more positive and effective with mopar type LSD units.

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