Question: C-4 Rear End Assembly

[Blue89]

Took my car to a dealer and they tell me that the rear differential/suspension mount is broken and caused it to rub against a few other parts that need replaced and suggested that I replace the total rear end assembly. Question is, my C-4 is a 1989, I found a rear end assembly from a 1986 and just want to know if it is compatible? Thanks for any help.

 

[toptechx6]

Some parts from the 86 are compatible others are not, you did not specify if your car is manual or automatic so first be aware that manual shift cars use the Dana 44 differential, automatics use a smaller Dana 36. The Dana 44 is stronger and some owners upgrade automatic cars to the larger rear end, that will require a different C beam and driveshaft from a manual car, halfshafts are the same.
The differential, batwing, driveshaft and C beam from an 86 will install in your 89 without any problem, but there are differences in the knuckles, hubs and parking brake so if you cannot swap the complete 86 rear suspension, hope that helps.

 

[Blue89]

Mine is an automatic and I didn't even think about what the other one is. Thanks for jogging my thoughts. Sounds too tech for me maybe I'll look around for an '89. What happens if I just keep driving it??

 

[John Robinson]

Salvage or New

You might contact this outfit and see what they have.

Corvette Parts - Taber Corvette Parts - New, Used, and Rebuilt Corvette Parts for all year Corvettes, Rebuildable Corvettes. We ship worlwide.

I have found with motorcycles that places like this have some really good ideas on what you will need to fix the car.

 

[Blue89]

Thanks again. I'll let you know how we turn out.

 

[toptechx6]

Mine is an automatic and I didn't even think about what the other one is. Thanks for jogging my thoughts. Sounds too tech for me maybe I'll look around for an '89. What happens if I just keep driving it??

Not really possible to answer your question without knowing exactly what is wrong with the car, my first suggestion would be to get a second opinion, preferably from a shop that specializes in Corvettes.
Having worked in new car dealerships my entire career I can tell you that service departments often recommend more than what is actually required, call it CYA if you understand my meaning.

 

[Blue89]

I understand and agree. I'll take your suggestion, appreciate it.

 

[ghertzog]

Other places to check out

Largest Corvette Salvage, Restoration and Used Corvette Parts Dealer in the Midwest.

Welcome to Contemporary Corvette

Good luck!

 

[Blue89]

I really appreciate the responses, especially the resources. One more question about the Dana 36 and Dana 44, is this data identified on the rearend somewhere?

 

[toptechx6]

I really appreciate the responses, especially the resources. One more question about the Dana 36 and Dana 44, is this data identified on the rearend somewhere?

Unless a previous owner changed the rear end all automatics have the D36, it should also be etched on the bottom of the pumpkin. The easiest way to identify them is by looking at the back cover, see the illustration from the FSM below.

 

[boomdriver]

yessir...the really good vette owners can just look and tell which it is. For guys like me I have to look at the tag thats on the filler plug. That should have the rear info.

Tip:
If the diff is replaced or serviced, be certain to top it off with fresh fluid and add the GM limited slip additive. That comes in a tube and has to be added for the rear to work right.

 

[Blue89]

Really appreciate it guys.......

 

[vetteoz]

Not really possible to answer your question without knowing exactly what is wrong with the car, my first suggestion would be to get a second opinion, .

Would have to be a major ( undriveible ) problem to warrant changing out whole rear

For guys like me I have to look at the tag thats on the filler plug. That should have the rear info. .

Tag only states "Limited Slip Lube Only"
Diff ID visual as shown above.
Stock installed ratio is listed on RPO label
Stock ratio is engraved on early and stamped on late diff head

 

[Blue89]

After I told them that it wasn't in my budget at this time, I picked up my invoice and it stated on it that I refused repairs and it was unsafe to drive!!! I took a chance and drove it back to my garage anyway, where it sits. ad

 

[So Bay Vetter]

If possible, Jack it , & take some shots & post 'em; Let's see if we can get you out of this W/O a whole new rear end. BTW- if the ash tray is dirty, the dealer will recommend a new console . . .

 

[Blue89]

Well, I crawled under and looked and if I saw anything I would have taken pics but with limited lighting (and eye sight!) I couldn't see anything broken, cracked or otherwise. I, however, noticed the bolt on the y-pipe hanger (the rubber one) was broken through where the bolt goes and the y-pipe was about 2" from it to the left and from the rear line of sight, it looks as if the rr wheel is cocked to the left, if that makes any sense. So, off to the phone and Craigs list to try to find a qualified Corvette mechanic to give me a second opinion. I'll report my findings. BTW, I agree with the ashtray theory.........!!!

 

[John Robinson]

Need More Information

I think it will help you and us with your problem if you could tell us what it was doing that caused you to go to the dealer in the first place.

Do you have a vibration in the rear end or a clunk.

Is the car squirley when on the road

Does it chatter when you turn a corner

Your problem may not be what the dealer told you it was at all.

 

[Blue89]

I bought the car the end of last fall and for the most part sat in the garage over the winter. I did drive it a couple of hundred miles in between. I took it to the dealer to have a general check to make sure it was in good shape mechanically before I stuck any $$$ in it for cosmetics. The only problem that I was concerned about was that the cruise didn't work (wound up just being a loose vacuum hose) and someone had hooked the radiator fan up direct, which runs all the time from when the key is first turned on. The rear end problem came from their inspection. They told me that it would take a couple of hours to trace down just why the fan was hooked direct and I told them that that would have to wait, as long as it ran, it was a good thing. Then it was that it needed a front end alignment and then it was the rear end thing. I do hear a clunk when I enter and exit the driveway curb but it sound like it's coming from the front end. There is a vibration about 60mph and again, it seems to be front end, it's not really wild, just aggravating. So there you go, I hope this isn't too lengthy.

 

[Blue89]

By the way, it doesn't feel squirly and I don't hear a chatter when going around a corner.

 

[John Robinson]

OK now then the vibrations could be any number of things.

Bad tire

Tires flat spotted from sitting too long on the same spot

Out of Balance

Ball joint or tie rod ends

Bad gas from storage causing the engine to miss.(That acts like a vibration)

All those are easy to check .

Out of curosity did the dealer ask you to bend over and tie your shoe just before he gave you the results of their inspection.