While looking at my rear shocks, I saw that the rear end was not dry. There seems to be a leak from the half dollar sized plug. I think it's a plug, not sure. Has anyone had any experise on this issue?


1999 Ram Vam 360 engine 1/2 ton


How do I check the fluid level and was type of fluid is used?


Thanks again.

 

That's the filler hole for the differential fluid. It's a plug made of a rubbery plastic material that just pops out, then back in.

 

Those plugs like to leak. You can get ones which expand in the hole as you tighten them for under 5 bucks, but the gear oil is pretty hard on the rubber and they will not last for more than 5 years.

Use 75w-90 or 80w-90 gear oil.

Synthetic is probably the most beneficial in the differential.

Some might say to use 75w-140.

Do not use Lucas oil stabilizer despite it saying it can be used in the differential. The stuff is well marketed junk which foams in the engine and differential. Foamy oil does not lubricate or transfer heat well.

The fluid level should be right up to the top of the bottom of the filler hole when the Van is parked level.

 

If I do not drain the oil and just filler up. What is best to use? Synthetic or regular? Or should I change it out which Im thinking I will have to buy and change the rear end gasket? Thanks again.


81,000 miles

 

You can certainly just top it up with convertional.

There is a chance it is a limited slip differential, which requires an additive.

At 80 k miles, if has never been done, I'd remove the cover, let drain overnight clean the magnet, and replace with synthetic.

You likely have wither the 8 3/8( 10 bolt diff cover) or the 9.25( 12 bolt diff cover)

If you do not want to pull the cover, you can suck. siphon it out through the fill hole.

 

Per the Chrysler TSB the Ram Van rear axle fluid is to be synthetic 75W90. If you use anything above the 80W90, bad things can happen to the rear.

 

I recommend the use of synthetic with the "LS" rating which means it already contains the additive for limited slip. If you are not sure and don't care to spend time researching and/or removing the cover this is the best choice.

It's a very good idea to siphon out the old gear oil before adding new. You'll need about 2.5 quarts of fresh oil for the 10 bolt diff, not sure about the 12.

As stated above just fill to the bottom of the filler hole and you are done.