Rear Diff **** Change

[LongIsland4x4]

I think the grease in my diff needs to be changed, its making a sound like its binding or not grabbing right away and people were telling me the grease could need to be changed.

I was wondering how hard it is to do, one guy told me you just take the cover off and the rest is pretty much self explanatory but I wanted to know if anyone has info on doing it thanks.

The truck is an '89 XLT with a 351

 

[Yardape]

Thats right you just remove the cover. one tip for you, put a drain pan under the diff, loosen the top bolts. And remove the bottom ones, then gently pry the bottom of the cover away from the housing. If you can, try to pry it away just a small amount so you can control the oil pouring out. Less chance of a mess that way. As the flow slows down you can pry out on the cover a bit more, then finally you are ready to remove it. There will still be oil in the bottom part of the diff, try to get as much of it out as possible. Be careful if you scoop it out with yor fingers, if there are metal shavings they could cut you. Other than that its easy. If you have a posi, be sure to add the friction modifier

 

[Broncobill78]

Changing the gear oil isn't too difficult, remove the cover & drain out the oil /emoticons/[email protected] 2x" width="20" height="20" /> Some guys take the opportunity and drill & tap a drain hole in the housing. Your 89' has an 8.8" rear axle and you'll need to pick-up a differential cover gasket for the reassembly.

Could you be a little more specific about the symptoms ? What kind of noise is it ? Do you hear it under acceleration/deceleration ? How about when traveling down the road with you foot off the gas ? Etc, etc, etc

 

[LongIsland4x4]

The noise is only under acceleration, usually in turns, but also happens sometimes while going straight. It seems like a very heavy vibration for a second or so then goes back to normal, theres a little bit of a "jump" after the sound like it snaps a little bit.

Thanks for the quick replies

 

[oktogo]

i just changed mine it was making the same sound it stoped after i changed it make sure u get a gasket and scrap the old one off before u put the new one on u will need about a gallon of 80-90 weight oil and a filler

 

[LongIsland4x4]

Ok thanks everyone, this seems pretty easy I'm off tomorrow so I might try and do the diff and my shocks tomorrow.

 

[oktogo]

good luck that oil stinks

 

[Broncobill78]

good luck that oil stinks

Yeah, that stuff is foul. It's the sulfur additives that help keep the gears from getting scored that make it stink.

 

[coolio2281]

iam changing my gear oil tomrrow, when u say filler what do you mean by that? and how can i tell if i have posi? i know the jack the truck up and spin the tire way but iam not going to be able to jack my truck up

 

[wileec]

iam changing my gear oil tomrrow, when u say filler what do you mean by that? and how can i tell if i have posi? i know the jack the truck up and spin the tire way but iam not going to be able to jack my truck up

The friction modifier will not overly hurt the diffential if it does not have limeted slip, but not adding it if you do is bad, a little like crossing the streams /emoticons/[email protected] 2x" width="20" height="20" /> If you look at the axel code on your door tag it should have a axel code, mine is I9 I IIRC a "H" means a limeted slip, but I am not sure.

 

[coolio2281]

allrite, thanks i appreciate it. tackling it this weekend