OneBeast88

I just got an 88 sport coupe. The rear differential appears to be leaking. I think it is coming from the rear differential cover. There is also some sort of valve on top of the rear end that you can not see without a mirror. I believe a lot of the oil is coming from that. Is that some sort of overflow / breathing system? I want to check the fluid level in it to make sure it is not too low.

I found what I think is the bolt to remove to check the fluid level and add more. I am not sure though, is this the right bolt to remove to check the level?



Here is the "breathing valve"



I took a picture of this thinking I could ID the rear end with it, but I checked my Haynes manual and this is not the right set of numbers.



Thanks.

JamesC

iTrader: (5)

The plug you show is the fill plug. Take this opportunity to simply pull the diff cover to check the ratio, then replace the fluid, which is probably almost 20 years old):

Here's how to determinne what ratio is: numbers are stamped on the ring and pinion:

41 : 15 = 2.73
41 : 14 = 2.93
40 : 13 = 3.08
42 : 13 = 3.23
41 : 12 = 3.42
41 : 11 = 3.73

JamesC

Viprklr

iTrader: (5)

IIRC the numbers that manuals use for identification are stamped on the axle housing. Mine was on the front of the pass side.

JamesC

iTrader: (5)

You're correct. I've never been able to use them because of rust. Anyway, even if they are readable, change might have occurred at some point.

JamesC

Viprklr

iTrader: (5)

I agree. There's no sure way of knowing without opening it up.

Mine had a lot of rust too. I took a wire wheel to it and was finally able to read the numbers with a light and looking at an angle kinda like this

sofakingdom

iTrader: (1)

Pic 1 is the fill plug.

Pic 2 is the vent. If it's leaking, about the only way is for the rear to have water in it, which is boiling and making the fluid spew out.

Pic 3 is the casting # of the center piece of the rear end housing. That conveys the extremely handy information that it's a 10-bolt rear for a Camaro/Firebird; in case you hadn't already noticed what kind of car it is. Useless for anything else.

Don't bother with the "codes". You need to change the fluid ANYWAY. Best way to do that, is to pop the cover off.

While you're catching up on the overdue maintenance, make a point of looking at the gears, because that's the ONLY WAY to be ABSOLUTELY CERTAIN of what ratio you have. And don't forget to look in the center of the carrier and see if it has clutches, so we won't have to see yet another pointless "do I have posi" post. (which it probably doesn't, at least it almost certainly didn't come with it)

OneBeast88

Thanks for the replies. I am going to change the fluid and inspect the gears tomorrow. I will post pictures to maybe help other people doing the same thing. Thanks.

OneBeast88

I lifted the car up on jack stands and made it sit level. I removed the fill plug and stuck my finger in there, there was fluid right below the threads, so it was not low.

I removed the bottom bolts on the cover and broke it free, after all the fluid dripped out I removed the rest of the bolts and took the cover off. I spun the wheel and counted the gears. I counted 40 on the big one and 13 on the small one. According to JamesC that makes it a 3.08. Thanks JamesC.

I spent a good bit of time removing all the pieces of the old gasket from the cover and the housing, that was the hardest part.

I then wiped out the cover as good as I could and noticed a magnet on it with little metal shavings. There was not a lot of shavings on it, I guess it to be a normal amount for a car this old. I did my best to keep dirt/debris out of the housing and cover during the whole process.

I lined up the old gasket and bolted it back up. I do not have a torque wrench so I just kind of guessed at it. I filled it up with some oil and put the fill plug back it. Then I put some engine degreaser around the housing to try to get all the old oil off. It did not work to well, when I have more time I want to get under there and clean it a lot more.

I checked for leaks after eating some lunch, none. I drove back to my house about four miles, not leaks. I will check again tomorrow morning. Thanks for all yalls help.

Here are some pictures I took during the process and an action shot . If anyone needs any more pictures of this area I took about 30 or so, just let me know.

sofakingdom

iTrader: (1)

To clean it up, put your Rhino ramps or your jack & stands in the tonneau area; drive it to the quarter car wash; stop at the parts store along the way and pick up a couple of cans of some one of the engine cleaners that's diesel fuel in a spray can, such as Gunk Engnie Bright or most of the store brands of engine degreaser; back the car up on ramps; get under there, and soak the funk real good with the cleaner; wait 5 or 10 minutes; soak it again; then blast the hell out of it with the Wash function. Rinse, then finish up with Wax to keep it from rusting so much.

Same thing works REAL GOOD in the engine compartment, as long as you don't spray with the high pressure right into a sensor or something, or at the distributor from too close.

Next time, do that RIGHT BEFORE working on it; then you get to stay a whole lot cleaner.

hwcoll95

iTrader: (6)

for comparison Auburn limited slip