So I made the mistake of putting Mobil1 75-90 gear oil in my newly purchased 2001 Dakota's LSD. Yes I did add the Mopar LSD additive. After a month or so I started to get a grinding noise when I started from a stop and went up hill to the left. I changed the fluid back to Mopar and the sound is gone away. However I am wondering if the damage is done and I need to replace some parts. Until this change I have never opened up the diff I have always just sucked out the fluid and pumped in new fluid. But this noise made me think I should crack it open and see what's what. What I saw was pitting or a valley on the face of the spider gears. It is uniform on all the fingers about the mid point. I assume this is from the gears not disengaging at the proper moment due to the inferior product. Anyway never having seen inside a diff I am wondering if this damage is new or it is normal wear on a diff. What should the gears look like in a 100k Dakota? Is some wear, marks, dings, dents ok? Should I worry?

 

Phil - sorry to hear about the Mobil 1. Bummer.
What did you use to suck the fluid from the differentials? Do you think you get it all out?

 

I use a suction gun. You can get them at autozone, pep boys, or any other auto parts store. I think I get it all out. That is how Jiffy Lube, and all the others do diff changes.

This is why I am wondering what normal gear wear looks like.

 

I sorry to hear about your luck but I use it in both my wifes 07 grand cherokee and my 07 dakota no problem.. Cya Slick

 

Slick,

Do either the Grand Cherokee or the Dakota have a LSD?

 

if its the stock one its most likely the differentials problem mine went out at 105k and i got it rebuilt with an aftermarket one and have had mobil 1 in it for 35k miles almost now and no problems. the stock lsd's are know to go bad and be pieces of ****

 

Sure do !!!

 

I have many people tell me just to suck mine out and replace it but really to me its only a couple bolts and a 5.00 tube of rtv sealant that will last me with 20 diff fluid changes but I like to take mine off just to make sure the spiders are ok and that nothing is worn. My 95 jeep grand cherokee doesnt have lsd but after 216,000 miles and only 1 diff oil change in its life the spiders and the ring and pinion looked brand new no lie of coarse only hope my welds hold up on the spiders lol

True lsd
IMG_0307.jpg

 

Anyone else have some other pics of their high milage diffs?

 

I will be doing a fluid change on mine this week, so I will try to get some pictures of it. Mine has 171,000 on it.