Whining Differential

[mdazzo]

My 79 has a whining sound coming from the differential.It can only be heard
when i take my foot the gas,(not under a load).I can deal with the noise,but sooner or later I want to repair.So my question is how much should a tranny shop charge me for this service ?of course I want to rebuild the differential and replace all of the u joints.Then the other side of me is saying to complete the repair myself...I am very handy
with vintage vw's beetles I just dont know why i am so in intimidated by the project. Any advice would help me out...
Thank You
Matt
long island,new york

 

[Ripp 73]

First let me say welcome to the CAC. I hope you have found some very useful information laying around here. As far as a cost on the differential... I'm not sure myself. Haven't had to go that far back on my car just yet. I'm hoping to get one more summer out of the rear-end. Doing work on the front part of the car first. I am sure someone will be around soon to help you with your question though. Just look around some more, there is always new information around here.

~Ripp

 

[Bob Chadwick]

How much of the work are you doing yourself. If you pull it, deliver it and put it back in I think the cost is in the $500 - 600 range. Van Steel lists their rebuild at $545.

Several of the vendors sell rebuilt units as well. Ecklers has them starting at $700.

 

[mdazzo]

Bob have you ever completed this project yourself?It seems to me to be a major job,,,how much do you think a tranny shop would charge me??

How much of the work are you doing yourself. If you pull it, deliver it and put it back in I think the cost is in the $500 - 600 range. Van Steel lists their rebuild at $545.

Several of the vendors sell rebuilt units as well. Ecklers has them starting at $700.

 

[mdazzo]

ripp
thanks for the email...just purchased this 79 with super low mileage..the only bad thing about the car is the rear.so folks are telling me the rear could last a very long time just the way it is...only being used on weekends and shows....

First let me say welcome to the CAC. I hope you have found some very useful information laying around here. As far as a cost on the differential... I'm not sure myself. Haven't had to go that far back on my car just yet. I'm hoping to get one more summer out of the rear-end. Doing work on the front part of the car first. I am sure someone will be around soon to help you with your question though. Just look around some more, there is always new information around here.

~Ripp

 

[Bob Chadwick]

I haven't done it myself, though I have done a lot of the component parts that would lead up to it. I suspect that a tranny shop would hit you up for at least $250 - 350 for 4 - 6 hours to take it out and put it back in.

Maybe I'm missing something but it doesn't look that hard. Half shafts and camber struts need to come off, with the camber struts the harder of the two due to the lower shock mounts usually sticking. Drive shaft off the front. Easy. Front differential bushing. Easy. Spring. Easy. Exhaust. May need to be cut off. I think that is it but someone will add to the list.

Support the differential and tackle the bolts at each end of the carrier. Getting the carrier to drop can be a bear with some people prying and others using a puller of some fashion.

 

[DMGroh]

I have a 96 LT1, but I am speaking from experience on a 4wd Pickup. The whine on coast is almost always an improperly tightened pinion gear. You have to tighten it "just so" and no more. There is (pickup, don't know about the vette) a crushable sleeve that puts a predetermined load on the pinion bearing. If it is not tight enough, it will whine...too tight and you will wear out the bearing. If you do it yourself, you will need a magnetic pedestal to hold your dial indicator to set the backlash. I think the job is a *****, but I am reluctant to let somebody else touch my car (or god forbid, my truck).

 

[John Kuzman]

Matt:

Take a look here:http://www.c3sharktank.com/tech2/rearsusp/rear1.html

 

[Hib Halverson]

Getting the diff. out of a C3 is not what I'd call a major job for an experienced DIY. On, the other hand, if you've not done work like removing transmissions or disassembling suspensions, then, it would be a major job.

I would not assume that a transmission shop can overhaul the axle, however, a trans shop is probably a logical choice for the removal and replacement part of the task. For the actual overhaul or repair, I'd have the trans shop send the diff to a facility experienced in rear axle service.

 

[GTR1999]

I do custom rebuilds on these all the time and I'm not far from you. I'll pm you some info.

 

[srthom13]

How is the rear gear oil ? Has it been changed lately or at all ?

 

[mdazzo]

I noticed that the fluid is a little gritty.So something has to be going on?
Do you think it could be as simples as a fluid change?

How is the rear gear oil ? Has it been changed lately or at all ?

 

[81 Corvette]

they aint cheap to have a shop rebuild. Mine was close to 800 in labor, parts included new ring and pinion, stub axles, u joints, carrier, bearings, bushings, strut rods (somebody bent the old ones). All told, it cost 2K. If you don't want to change gear ratio's you'll save 250+-, if your carrier doesn't have spun bearings, thats a savings, and if your stub axles are still good, yet more savings. If those three things remain, you should be in and out for under 1K.

I suggest more gear tho. I went from 2.87 to 3.55 and love it.

 

[Bob Chadwick]

I noticed that the fluid is a little gritty.So something has to be going on?
Do you think it could be as simples as a fluid change?

That's easy to do and cheap. Give it a try. It can't hurt. Make sure you use two bottles of GM positraction additive.