I picked my 1999 coupe from the shop this afternoon. My excitement turned immediately to depression when I accelerated down the street.

I bought a new 3:42 gear differential, new A4 transmission, and torque converter. I had a very experienced local shop do the install. A few days ago they made a comment to me about the whining in the rear end but thought maybe because it's new it would loosen up. The owner even recommended doing some figure eights in a parking lot.

Symptons:
The whining occurs only when accelerating at all speeds and gears and all throttle levels. You can cruise at 70 mph and just give it a little gas and the whining starts again. When you let off the gas, the whining goes away. When you slow down to about 35 mph to a stop the whining starts up again. It is clearly in the rear of the vehicle. The slower you drive the lower pitch is the whine. The whine is heard in reverse as well. I went to a parking lot to do the figure eights. Going real slow and turning to the left, it seems the gears are off a bit. Almost feels like it's "skipping" I can't feel the same feeling going to the right.

Besides the whining noise which is really loud, the car seems to run fine. It accelerates and takes off super quick with the new parts especially with the blower that was installed two months ago.

Things I checked:
The fluid is at the correct level. When in park and I give it gas, there is no whining or any other sound. Just the awesome sound of the rpms. When driving and put in neutral, there is no whining.

I picked the car up almost the time the shop was closing. The lead tech told me the whine is still there and to call the company first thing Monday morning where I bought the trans and diff from. Now I have to wait until Monday to even ask them this question.

My Situation:
I was going to do the install myself so I purchased the transmission, differential, torque converter, flex plate, and all Amsoil Fluids for the diff and Tranny myself. This local shop doesn't like to install customer parts, but since they worked with this supplier they said they would.

Anyone have any ideas what it could be and why? Any Advice? Obviously, I will call the company I purchased these parts from Monday morning, but I am dreading the response they are going to give me.

 

Sounds like you got a differential with either alot of miles on it(worn out) or the gears are not set up properly. I couldn t say for sure unless i looked at it myself. Did u buy the diff used? The way you described it i would say its the ring & pinion gears whining. I can t believe the shop said to "do a couple of figure 8s" and that it needed to "loosen up some". Are they a reputable shop? I hope they ante up and make it right(whoever s fault it is).

 

Had this exact problem last year. Whining in all gears and only when you press the gas pedal. Would go away as soon as I let off. Turned out to be pinion support and a broken clutch disc in differential.

 

Thanks guys.

It was a brand new differential (rebuild). Seems like the diff will have to be pulled out and sent back.

 

with IntoC6s.

Either the parts are not new or they were not properly set up. If this shop installed the ring and pinion they must not know how to set it up or screwed it up in attempting to do so. Differential whining doesn't get better on its own or by beating on it. Are you sure they added lubricant??

 

This is a specialty shop that does transmissions and differentials. They are all over this forum. I just have to wait and see what they say.

 

Had this same problem when I bought my 03 in may. Was a built diff from a well known co. Granted, the rear had 17k on it but when taken apart, clutches and gears were completely worn.

 

the diff is not set up correctly. perhaps pinion depth??

 

Your shop is a vendor on here? Or they just look at this forum?

Regardless, can't believe they would say "do some figure 8's". From everything I have ever read or heard....that would be about the last thing you would ever want to do. This plus the old logic of "its new...hope it breaks in and eventually goes away"....really hardly ever works. That usually to me if the first tell tale sign that the shop that did the install knows it aint right and they are stalling or hoping for a miracle. I been down that road before with 2 transmissions lol.

Good luck...keep us posted. Hope your shop fixes the repair for free. Really can't see this problem being an error on your behalf.

 

Additive won't stop any sort of whine. The additive is actually in there so that when you go around a turn and the wheels turn at different rates, the clutches will slip and you won't get the back end bouncing around or popping. This is for all posi units that use clutches not just IRS vettes. The purpose of the figure 8's is that sometimes the clutches need to get the lubricant in and around them enough that the popping and bouncing doesn't occur. Again, it won't stop any sort of whine which can only be bearing or gear mesh noise.

Your symptoms sound like your gears are not setup correctly. Some gears will whine but this sounds excessive and should result in a correctly setup gear or a new set of gears because they are not good from the manufacturer that supplied them to the shop. Call the vendor on Monday and good luck with it.

 

I called the Vendor of the Differential this morning. He already new my phone call was coming since he was reading this post. Vey nice and friendly. They are bulding a new one for me and sending it out in a couple days. They will figure out what happened when the unit comes back. This is what I call great service. Now I can sleep at night.... Thank you guys.

 

if all works out well, give us the name of the vendor. He will deserve a pat on the back for stepping up to the plate to make it right.

 

That s what i call good business! Sometimes, brand new parts are defective and you can t tell till its already installed. Props to the vendor for doing the right thing!! Good Luck!!-Jason

 

Mine did that.. after a few hard launches at the strip in Vegas. I didn't even break a 2.0 and f'd up the rear end. Drove 400 miles home with that lovely whine.

 

I'm curious to see who covers the additional removal and installation costs.

 

My wife is already pissed with the cost of the first install and told me to get a second job. Looks like I'll have to find a third job for this next install.

 

I got a diff. put in, completely rebuilt,It whined on the way home from the shop, They told me they put extra clutch packs in when they rebuilt it, that may be causing the whine,I drove it all last summer and it never got any worse or better.This was a very reputable shop that did the work??? I am bringing it back in the spring, I'm not really buying the clutch pack thing!!!!

 

Well unfortunately that is not always the case. The OP of this thread did buy his differential from RPM. We spoke with the customer today and agreed to build him another differential and get it sent right away. When there is an issue like the above it could be caused by a few different reasons. When we get the noisy differential back from the customer we will try and figure out the reason for the noise. I realize that there is an expense to the customer for the additional R&R and freight and that is handled on an individual basis. If we determine that there was a faulty component or workmanship on our part I will more than step up and take care of the extra expense.

 

Rodney's a good guy and I'm sure they will get you all fixed up, every now and then a new part goes bad.

 

This is a perfect example of why RPM has so many loyal customers!