what kind of Differential Maintenence can i perform or have a shop do?

There is 100,000 miles on my 1986 trans am. It is a v8 5.0 305 tpi fuel injected.

Any suggestions on how i can just improve my real axle? It seems fine but i'm over hauling and tuning up whatever i can since this is my project car to do anything and everything with.

I know little about the rear axle. I know the gears themselves can be exspensive but how much do you think labor could eat my wallet?


also how hard would it be to replace the fluid in the gears with that racing purple fluid i keep reading about?

 

getting gears installed is gonna cost you alot at a stealership, but thats the only route I would take, becuase setting backlash, and getting everything right in there is hard I've done it at school,and aced my test on it, and I don't even trust myself enough to do it when I buy my gears and new posi unit its going to a shop to get installed even though I hate taking my car to a shop

 

setting up gears isn't THAT hard if you take your time and pay attention to what you're doing. I've set up 2 of my own so far, 1 has about 10k miles on it with hardly any noticeable whine, the second set is about to go into the car. the only way to learn how to do it is to actually do it. he said its his learning car, what better what to learn. get your hands dirty and do it.

gears will run you around $175, get a complete install kit for another $75ish, and get a dial indicator with some kind of decent base to it and you're set.

changing fluid is a piece of cake.

 

ok thanks, any kind of guides or videos or books or sites that can help take this step by step?

 

I *think* there is a tech article on this site about changing gears. if not, there are plenty of sites online that you can search for that will give detailed instructions. also, I know when I got my first set of gears, they came with some pretty detailed instructions on how to set them up correctly.

 

ok sounds good thanks. Now i'm assuming i have to remove the whole thing and set it down on a bench correct haha. How heavy is it and can 2-3 people easiley hold it to bolt it back in?

 

my first set I installed in the car. this last set I'm swapping complete rearends so I did it on the bench. having it out of the car is definitely easier and I would highly reccomend doing it this way if you'll take the time to unbolt everything and drop it completely out, however its not necessary to do it.

any shop you take it to will do it in the car as they'll just throw it on the lift and get it above their heads. doing it laying on your back in the driveway is a little more difficult.

 

fair enough thanks for all your info.

 

how can you replace the fluid if its still in the car. i know the lid is on the side and gravity will just have it pour out the side as i'm trying to fill it up. or maybe i'm totally not thinking correctly on where the fluid goes.

i'll get it on a bench if i can just seeing my options if i do and if i dont

 

I know on the 9-bolt cover there is a rubber plug that you pop out and fill through it. on my LT1 rear, there is a pipe plug in the side of the housing. yours will have one of the two on it.

 

ok perfect, thanks for the info. do you know if still attached to the car what is the best way to drain it? just unbolt the back cover?

 

Just unbolt it, give it a little pry on the bottom. Will drain. For a thourough drain, get your finger in there and scoop out as much oil as you can. For refilling, get some 80w-90 gear oil, and if it's a limited slip diff, some limited slip additive.

For the 9-Bolt Borg Warner, after you reassemble, pull the plug on it, and fill it until it starts to drip from the hole. I dunno about the 10 bolts.

 

ok perfect thanks for all your info guys

 

If it's limited slip, you need to add the whole amount of additive before you add gear oil.

Oh, and totally invest the $6 in one of those quart bottle gear oil pumps. Gear oil is thick, and the rear of your car usually isn't designed with filling the differential in mind. Some tubing works just as well, but then you still need to have the bottle positioned akwardly. With the pump, it's REALLY easy to fill your diff. Plus, you can lock the pump down, and it's a nice cap for your leftover fluid.