Looked in the DIY section but couldn't find what I was looking for. I want to do the rear diff fluid but I don't know what to buy or how to do it.

 

I use Mobil 1 synthetic 75w-90 in mine.. all you do is put a pan under the rear take out the 10 or 12 bolts holding on the cover and pry the cover off slowly and the fluid will drain out.. after its all out run a bead of blue RTV silicone around the edge of the pan ( make sure to remove the old stuff first ) put the cover back on the way it came off re insert the bolts tighten to spec (not sure what it is off the top of my head) then pull that little rubber grommet out and put the fluid in there till it starts to run out of the bottom on the hole....

oh yeah... make sure to add 7oz of friction modifier if you have limited slip in the rear axle..

 

I use synthetic also, but I use the Lucas brand. If it has never been changed, i would go down first and by a new plug. They can dry rot and leak. Plus when they are old, taking them out will tear them.

A new plug is very cheap and be brought with the new fluid. It will take a new bottle of the 7oz friction modifier as Old_School said, then not quite two bottles of the synthetic fluid.

Fill up until it runs out the plug, then cap with the new plug.

When you put the bead of new silicon, make sure you go around each bolt hole, circle them, then let sit for about 5 minutes to form a skin, then bolt new cover on. I tighten the bolts down as I would a rim. Tighten one bolt down, not all the way, then go to the one on the opposite side and do it, then back to another one on the opposite side of the one you just did, until you get them all tightened down to specs.

This will insure an uniform spreading of the silicone.

 

Thanks guys, how do I find out if I have LSD.

 

Lift the back wheels so you can turn the freely... it both wheels turn in the SAME direction its LSD, if both turn in the OPPOSITE then its an open differential...

Also, you can find out buy requesting a build sheet from dodge ..... someone correct me if im wrong but, i think its listed on the label in the glove box?

 

I used some konklin synthetic, after putting it in I noticed that it was for a Mack semi, oh well

This thread will show you how to tell the difference between lsd and a regular open diff https://dodgeforum.com/forum/1st-gen...rebuild-4.html

 

Make sure you put RTV on both mating surfaces. Also, use a good RTV or you will be doing it again in a few months (ask me how I know... lol). I found Ultra Copper by Permatex to work well.

 

I did the same a few months ago and i bought a plug and used royal purple. I was told it was good and i hope so because it is expensive compared to the rest. Should take 30-45 mins if its your first time doin it. Had mine done in less than an hour.

 

That's where mine is,it's faded but still readable....I put my VIN in compnine
and got a buildsheet full of info on my truck.Not sure if it's all accurate but it seems to be...
A question guys....a couple of the gear oil brands like Mobile1 have LS on the bottle.
We still have to add the friction modifier right?? Also, what's up with the 4 oz bottles of it? The book says 5oz, you guys say 7oz(which I'm going with) so 2 bottles have to be purchased? I gonna look in other stores and see if there's bigger bottles....What brand of that do you guys like best?

 

That's the same kind I use. The stuff is great and no leaks!