[updated:LAST EDITED ON 22-Feb-02 AT 06:38 PM (EST)]I have a 90 EB bronco the axle code is H9 which i believe is a 3:55 limited slip. It does not seem to want to lock at all. On ice, snow mud or anything. I am also getting some drive train noise. It sounds like i got big mudders on it when i"m going down the road. Could they have somethig to do with each other? I just bought it a couple of weeks ago. I have not had a chance to really check it out yet. Any suggestions? Any info would be appreciated. Thanks!

 

I have the same set-up in my 89. Mine's still working after 141K miles. I've read where the OE track-lok units from Ford aren't noted for being very robust under extreme usage.

I would change the rear axle lube, as a starting point. Ford says you should have a 'limited-slip' addative in the lube to insure proper operation of the differential. When I changed to lube last week, I found it to be a nice dark brown color, indicating that some water had found it's way into the housing! It wasn't too bad, and the lube was still doing it's job, but the fresh lube should go a long way to keeping the gears in good shape!

You have to take off the read diff cover plate to drain the lube. Get a new gasket and some high pressure RTV sealant. I used about a gallon of 80W90 lube, and a tube of limited-slip addative when I filled it back up. When you have the diff cover off, you can inspect the internal gears, etc to see if there's something loose, broken, or just plain worn out inside. Also, there's a lip on the bottom that catches some lube - use a rag to wipe out all the old stuff you can. Since mine had some water contamination, I used a spray can of WD40 to try and rinse as much of the old 'gunk' out as I could - then let it drain for a half hour.

When you put the cover back on the diff - make sure both surfaces are clean and smooth. I ran a small bead of RTV around the inside surface of the cover - inside - of the bolt holes. This should insure a good oil-tight seal when its bolted back up. I then placed the gasket on the cover, and with my fingers, put a real thin film of RTV sealand on the gasket surface that will then mate with the axle housing. If you wish - you could clean up and paint the diff cover before re-installing - or spend some $'s and get a new chromed one!

I bought a cheap-o tube filler that fit onto the new lube bottle to refill the axle. I put the tube of limited-slip addative in first. Good luck...it's a messy job.

 

Thanks for the info. I appreciate it Where can you get the additive and is there any better than others? I am probably going to do this tomorrow on my day off. Thanks again!

 

I got mine at my local parts store - it was right next to the diff lube's, in a plastic tube, like a toothpast tube. I don't know if some is better than others - if they conform to auto maker's standards, they should be fine - no rocket science here! Good luck.

 

Thanks for the info I did it today it definately helped out the limited slip. and if at all possible I believe it got a litle quieter going down the road. I appreciate the help.