I'm sure this has been covered before but I can't seem to locate it. I'm running a '99 Lariette 4dr, 4.2? When I'm stopped at an intersection and mostly when I turn left the rear end seems really tight until I straiten out. Currently I don't think there is any howling from it. I have heard that I should add an additive that will help this but I would rather fix it right the first time if it isn't too expensive. Any idea of what this might be and if it is something one can do in their backyard?

 

jack it up and see if both tires spin by hand. friction modifier is what you add, but at this point you cant undo it and will have to drain and refill.

 

First determine if you have a LS rear differential. There is a tag on the rear housing that will specify what gear ratio and whether it is LS. Friction modifier is for LS differentials only.

 

probably should do this if youre not familiar with how different differentials feel. look for the axle code

 

could have a broken spider gear

any grinding noise or binding??


Usually LS just slip more when the fluid wears out, and chatter when they grab/release/grab/release etc

 

No grinding or Crunching noise.....yet anyway..... or at least that I can hear and I expect if it was the gears I would most likely hear it :-) It does feel like something is binding when I turn in a corner from a stop.
I'll check the tag this weekend and get back to you.
Thank You

 

you can also check the "axle code" on the door jam sticker. Cross reference the two digit code with a list.

That way you don't have to crawl under the truck

 

Thanks Patman. I'll cross reference that tomorrow. However I did manage to crawl under her earlier today before the rain started. I'm pretty sure the tag tells me to use synthetic OW140 oil and the code is, or at least I think it is, LS829A
Now, this is my first RWD in over 20 years and I noticed something odd, or at least it was to me. On my 77 Chevy, when both rear wheels were clear of the ground you could spin one side and the other would turn in the opposite direction no matter what direction you were rotating the wheel. I tried this on my Ford. When I rotated the drivers side wheel in a forward direction the opposite side rotated forward as well but when I rotated it in the reverse direction the passenger side didn't rotate at all. Is that normal?

 

Put it in Park when you do it. Each rear wheel should be very difficult to turn if you have a limited slip but if you have an open rear the other wheel should go the other way.

 

Just another thought;
do you have rear disc brakes??

If so...might be the emergency brake pad deteriorated to point it came loose

 

Update:
Changed the gear oil in the rear end yesterday. Did not go with synthetic but with regular 80 - 90 gear oil and limited slip additive. So far it seems to have cured my problem. The oil that came out was a milky black so I figure it must have been a long time since it has been changed and the best thing is there was no metal pieces laying in there!!!!:-)
Next up fuel and transmission filters need changing and after a long drive on a wet and dark highway last night.......... A new set of headlights are in order.

Thanks again for everyone's help!!!! Much appreciated.