v98roadie

I just had a rebuilt differential installed in my 02 coupe. Went from 2.73 to 3.73, along with the diff I had the HPE diff brace installed. Since the rear end was first installed there has been noise under acceleration that was not present before. The guy that built the diff has had it out twice and replaced the gears, carrier and bearings. Tolerances are spot on, the guy that did the work is a Corvette guy and he is "the" go to guy for drive train work like this. He has been very helpful but puzzled just like me. I picked the car up yesterday and I am going to drive it hard for a couple hundred miles then he is going to tear it down again. I took it out this morning for a 50 mile drive at speeds from zero to one hundred and back. The noise sounds like you have a stethoscope on the rear diff while driving down the road and its present under acceleration at all speeds. Strange. Anybody had a similar experience? I am beginning to think it has something to do with the brace. Thoughts? Ideas? Thanks in advance.

blackvette97

My guess is that it is in your rear end gears. Either they weren't set exactly right or I have heard of some gears just run a little noisy even when they are setup correctly. What kind of gears where they? I just bought a set for my car red box motive gears just looking for someone to install them. Was hoping that is not going to be my case when I drive mine after the gear swap.

v98roadie

I've asked the guy what brand the gears are, I'll let you know. After a lot of debate and discussion I/we think it is the gears. I am going to run it another couple hundred miles and see if they quiet down some. If not, I may just have to insulate the rear of the car or turn the stereo up louder! The performance difference is amazing.

0HoosierPE

Do you have the torque limiting mount or the diff strut kit?

If you have our strut kit, and the rods are adjusted incorrectly this can cause the diff to whine.

If you can call the shop or email us we could get into further details with options to help with this.

Jeremy will be out of the shop until 1pm who is our lead tech in the shop and does all our diff builds.

260-245-0352 or info@hoosierpe.com

Here is a link to our instruction manuals on the diff strut kit.
http://hoosierpe.com/tech-info/dte-c...race-assebmly/

We can try to help you out.

Thanks,
Jason Massey

Stroker87

I had RPM Trans swap my gear from a 3.42 to 3.73 I have a barely noticeable whine accelerating but when costing I have a noticeable whine/howl when the installed did the test pattern it was spot on?

I've swapped gears in a few cars/trucks over the years 1/2 of them had some kind of noise all was professionally installed

v98roadie

After much discussion and some research I have come to believe it is the gear set. Nothing at all to do with the HPE brace. I just have to decide how to live with it. I guess I can resort to Dynamat and crank the stereo volume up! Unless I am being mislead there is only one manufacturer still making the gears for the C5 differential and they have had some quality control issues and had a bad run of gears previously. At least I'm not experiencing flaking and tooth breakage like some others I've heard about!

v98roadie

One last post on this discussion. I took my car back to the guy that originally installed the gears and he did everything possible to make things right. He installed another set of gears (the 3rd) and worked with it until the noise is barely noticeable. I learned a few things from this experience, 1) going from 2.73 to 3.73 makes a huge difference in the performance of the car, 2) 3.73 gears are likely going to be noisier than the stock gears but not so noisy as to be unbearable, 3) make sure you have someone that knows Corvette's and gears well before making the change. Would I do it all over again? Yes! Would I use the same guy? Yes! Is it the single best performance mod for an A4 short of forced induction? Yes!

blackvette97

Just had a set of new "Motive" 3.90 gears installed in my car after breaking an output shaft in the rear end and only drove it to the storage place about 25 miles away and it sounded like perfect no whine on light acceleration. TPIS in Minnesota did mine and he said to break these gears in very easy for the first 250-500 miles and should have no problem. So far was very happy but tough to tell the difference since it is cold here and roads were cold all I got was tires spinning no traction to really feel the difference. 2.73 to 3.73 had to make a Huge difference. Now you just need a pro charger

Joshboody

the diff on my car was replaced before I bought it. It has a slight whine with any load. I've beat the car on the track a few time and no issues.

I do have the DTE strut brace, which was already installed. DTE can you chime in about confirming pre-load? I'm thinking to loosen each rod and do the pre-load procedure per the manual... 1 turn and tighten locking nuts? Does the drivetrain need to be lowered slightly to do this? Haven't taken a closer look yet.

2000BC

I installed my DTE on a lift and as per the manual, snug up, one turn, tighten. No problems. Went to 4:10's and a little whine but I think it sounds good!

Stroker87

I jumped from 3.42 to 3.73 and was really impressed for such a small change in ratio's

0HoosierPE

We have specific instructions on the preload process - we recommend you to visit the following link and select your kit for the step by step installation of these kits.

http://hoosierpe.com/tech-info/dte-c...race-assebmly/

If you have problems, please call us anytime from 8:30am-5:30pm EST. With the holidays around the corner - we will have limited help tomorrow after 12pm and then shut down 25th and 26th (Thurs & Fri), but will return Mon the 30th.

Safe and Merry Christmas everyone.

Cheers,
HPE-DTE Team
Jason

v98roadie

v98roadie

I'm telling you this, the 3.73 is perfect for the A4 IMHO. I was thinking 3.42 but the gears were hard to come by, 3.73's were readily available so I took the plunge. The car runs better, sounds better and makes me grin from ear to ear every time I accelerate! I think the slight noise I have left will probably go away with time. No one but me would even notice it at this point.

Stroker87

My car is a manual I was thinking 3.90 but I do a lot of highway driving so just did the 3.73, in 1st from a low roll the car felt sluggish till it hit the power band (like a turbo) now it just gets up and go's 1st and 2nd are useless, flat shift 3rd it dances so does 4th just a little less.

I babied my car for 500 miles when I did the gear at 1st I didn't have any noise as it broke in it started to whine some it's not that loud or noticeable with the radio on low volume you can't hear it.