Joe3571

Hey guys hope everyone is doing well. I am having an serious issue with my 84 corvette I copule weeks ago I started getting loud scraping sounds for one of the rear wheels along with popping noises when ever it would go into gear turns first both my rear brake calipers pistons had gotten cockeyed or angled against the inner brake pads.

so I was thinking well maby that was the problem so I replaced both calipers and pads had the rotors turned. well that only fixed part of the problem. with just the calipers them selves. I do believe I might have a bad u joint when ever I shift from park to reverse or dive.

soemetime's ill get a ping or pop from the rear and the car jerks kind of hard. going down the road I can hear a slight squelling followed by loud scraping noise with some popping or when I get hard on the gas
the rear axle shafts do have some play but only if the car is off the ground. if it is sitting on the ground you cant move them forward or back. the rear diff fluid is very dirty and the seal is leaking. all the machanics that have road with me and heard the car all say the same thing either bad ujoint's or bad diff. if it is the rea diff that's what really scares me cause that is an real expensive fix. so could somebody perhaps tell me what differential my car may have come with

its a factory original 1984 700r4 auto apparently chevy made 2 different ones that year.

eutu1984

Auto's had the Dana 36 and stick's had the Dana 44.

Joe3571

ok is that the 8.5 rear end ? or the other went to the parts store the other day was going to try an replace the wheel bearings and they asked me is it the 8.5 or 7.5 or something to that extent to which I was like hell I don't know there is two different size bearing's?

but thanks ill start looking up prices for a replacement dana 36 I guess I wll have to somehow replace it myself cause it seems a lot of the differential shop's wont or don't want to touch my car something vette's scares them it seem's but on the other hand I probally would not be able to afford to pay them anyway. now if I could just figure out where to put jackstands under car woth out it falling an crushing me anyone got any idea's there is only 4 places to jack the car but nowhere I can see to put stands. chevrolet obviously did not want anyone to be able to work on their own cars.

eutu1984

before you yank out the diff. I would make shore that that is the problem. if you need to place jack stands underneath you can see the frame rails where you can place them other than the jack points. Just take a good look. They don't need to now what size diff you have to replace your wheel bearings. The wheel bearings are hub assemblies and separate from your diff. If you are going to work on your own car you need to get a FSM (Factory Service Manuel). https://www.google.com/webhp?sourcei...rings&tbm=shop

fredd1

Re. the wheel bearings, they were probably asking what size wheels ie. 8.5" or 9.5" rims. If you have play in the half shafts chances are you have worn u-joints. Change them and the differential fluid before you think about replacing the diff. (don't forget the GM recommended LSD additive when you change the fluid). The '84 rear is a Dana 36 with 3.08 gears on (most) A.T.s.

WVZR-1

There were NO D44 rears in '84 "NONE"!

OP - you need to have the diagnostics done before you just take it apart. There are any number of situations you can have and a person just needs to understand differentials and basic drive-line to do the diagnostics. The guy at the AP store was asking you the questions that his electronic catalog was asking him. There only one rear hub/bearing.

If you need bearings that's one thing but the rears aren't inexpensive and if it's NOT the problem then you've maybe spent 2 times the cost of an actual repair. The replacement of the bearings for a novice can be very challenging. If you don't customarily do your own work it would be a real challenge.

If your differential is bad you want to replace it and not repair the '84 probably. There were two D36 carriers in '84 and one was "junk" and required several hundreds of dollars worth of parts to update if it went out. You will want a D36 with a 3.07 ratio. There were nothing else in the '84 except for a couple hundred 3.31 and those were MT.

There's no way to tell until disassembled which carrier is in your rear.

Have you ever had the rear serviced? Have you ever done u-joints? How many miles and how long have you owned it?

gerardvg

Hi

First thing to do is jack the rear at the sill (there are markings where to put the jack on the sill with a small notch cut out) when you have a rear wheel of the ground and your "hand brake is off". Put one hand on top and one the bottom of the tire and pull the top/push the bottom of the wheel to see if there is any play in the bearing hub, then do the same on the sides. If there is play "replace the wheel bearing hubs"

Iff they are good you will need to raise the rear of the car (both sides) and support the car with stands, now crawl underneath and spin the wheel by hand and listen for any noises.
Usually the universal joints will make a "click" sound as you turn the wheel, the universal joint closest to the brakes go first.
The grease disapears and you will have rust powder or the universal joint will be siezed. Replace them with SPICER brand they are one of the best brands and last longest.

There is nothing wrong with the D36, get another one if you need a new diff. They are cheap and you can get the whole assembly with hubs, the ratio codes are stamped on the support housing.
the 3.07 ratio is good, you do not need a drag racing ratio as the
T700R4 has a great first gear to launch with.

My 85 has an auto trans and D36 rear, my car is supercharged and has been for around 8 years now no problems with the D36 (yet)
The auto trans and half shafts are the weak points, for a manual trans yes you need a D44 but auto transmissions are kind to diffs.

Even drag racers are blowing the D44 rears in the 10-11 sec quarter mile bracket.

The D36 is fine for auto trans road cars unless you are below 12 sec quarter mile times, i am at the D36 limit and have no complaints.

Good luck

JrRifleCoach

It's time to pull the axles for U-joints. While your there look to replace the rear wheel bearings. Don't forget the main drive shaft u-joints and dog bone rubbers, toe-rod ends and center. Might get a new pinion seal & service the diff.

What? Did ya think the rear end of a Vette that's 30 years old will last forever?

Good Luck

HlhnEast

It is most likely the U joints. The rear bearings may be bad as well thinking about the scraping comment. You are looking at $15-$25 each for U joints and around $85-$120+ on each rear bearing assembly for USA parts. Here you have to ask yourself if you plan on keeping your Vette long term and how you feel about replacement parts. I personally would buy either Spicer or Precision Ujoints and would go with Timken, Moog, SK, Raybestos on the bearings. You will also need to go to a Chevy dealer to get 2 "teflon" washers (GM part # 14076924) that did not come on your 84. They are about $6-$7 each and were added in later years to prevent popping and squealing. You may also have an issue with your E brake assemblies as they are inside the rotor.

You really need to take a serious look at it before buying up a bunch of parts or go whole hog on it "while your in there" and rebuild everything so there will be no issues during your ownership. If you cant do your own wrenching it will get very expensive very fast.

Good luck!

FaTnBaLd

Definitely need to scrutinize wheel bearings and u-joints before you dive into a rear end.
I too have rear noises. Have it apart now, the u-joints werent great and the pass side strut rod bushings totally shot.

J's Nest

I had a simialr noise in my 87. I noticed it most when going slow. It would squeal like a brake pad, but it was actually one of the half shaft u-joints. That was several years ago, but this year I had all the U-joints and bushings on my car replaced. No noises anymore.