Just got the GTO back after the rear diff swap...

Like many of us, my car was plagued with the rear diff whine. Took it in to the local Pontiac dealership on Monday to get the new rear end, and just got back from picking it up.

It was an all around pleasant experience. They were really cool with me. Part number for the new diff is #92187413 - which from what I understand by reading on here, is the good diff. The diff took about 2-3 weeks to arrive.

I also told them about other common annoyance I've been having - the clunking sound that comes from the right/rear quarter panel area when going over bumps. I printed out a thread from here and gave it to them in order to help them pinpoint the problem, but they were unable to find it. The tech who worked on my car was gone for the day when I picked it up, so they said to bring it in tomorrow and I can show them exactly where the clunk is coming from... since I know exactly where.


So now I have the wonderful duty of breaking in the new diff with no speeds over 55mph for 500 miles.

I got my trip meter counting down... only 492 miles to go.

gee when I went to a dealership here in DFW i was told thats just how they are and they all do it.

Pucci

i just got mine back 2 days ago too, it took them about a week to get it in and only a half of a day to install it...i always have a good experiance with my dealership!!! no more whine in mine now!!!!

My dealer just agreed to swap out the diff, should be doing it this weekend, hopefully it fixes the problem. It was pulling teeth to get them to agree to it though.

Quote: Originally Posted by ZUMin3K... My dealer just agreed to swap out the diff, should be doing it this weekend, hopefully it fixes the problem. It was pulling teeth to get them to agree to it though.

Looking at the receipt I got, it took about 2.5hrs of labor to do the swap. They forgot to order the TTY bolts when they ordered the diff, which is why it took a couple days longer, but that's OK. I don't drive the GTO during the week anyway.

Quote: Originally Posted by firefly9r68... My dealer just agreed to swap out the diff, should be doing it this weekend, hopefully it fixes the problem. It was pulling teeth to get them to agree to it though.

I just went in there, told them about the whining sound, when/how it happens and specifically where the noise is coming from. 10 minutes later they tell me there is a TSB on it (which I knew about already ) and that they're not authorized to do work on the diff. Instead, they have to order an entirely new unit. No hassles, no telling me the noise is "normal"... none of that.



But man... this break in period SUCKS! I drove the GTO today to work. The stretch of highway between my house and work is a good 6-7 miles of perfectly straight, flat road. And here I am plodding along, going 50mph.

I even had a riced out Cavalier pass me, and the driver was looking over like, "WTF?"

Hehe, luckily I have a 2 mile drive to work, no traffic, but plenty of stops that keep me from going more than 45 mph, so it shouldn't be too hard

So, did the diff. replacements fix your whining issues? I had mine replaced with the new part number, but it still although now at different speeds. Should I go back to the dealer and ask them to replace once again?

Quote: Originally Posted by GTO Lover... So, did the diff. replacements fix your whining issues? I had mine replaced with the new part number, but it still although now at different speeds. Should I go back to the dealer and ask them to replace once again?

Well, I only put 20 miles on it with the new rear end, and no noise so far. So it's still too early to tell.

At the way I drive my car, I put on maybe 1500-2000 miles a year, tops. So if it does infact start whining again after 7500 miles, it'll be a long time before I notice it.

Awesome. I just got a new differential, and asked about the break-in period...

...service tech says NO break-in period or driving restrictions. Sigh...

While the dealership never specifically mentioned anything about a break in period... I'm just going off what I found while searching on here, and 500 miles seems to be the concensus on a break in period. If I find otherwise, I'll change my driving habits for the next 500 miles.

Quote: Originally Posted by Black No. 1... ...service tech says NO break-in period or driving restrictions. Sigh...

There HAS to be some kind of break in when moving metal parts like that are involved.

Quote: Originally Posted by Black No. 1... Awesome. I just got a new differential, and asked about the break-in period... ...service tech says NO break-in period or driving restrictions. Sigh...

They told me that on my first replacement also. On the Second Replacement they told me to follow the break-in on the invoice...

From an earlier thread : "The break-in note on the invoice says : customer not to drive over 55mph for first 500 miles. I also have been told to vary the speed. Both these constraints will make for a fun commute. I also remember someone saying to go 15mins , then cool down , then 60 mins , then cool down , then replace the fluid at 500 miles. So I did the 15m and 60m thing and now just have to watch every driver fly by me for 400 more miles..."

I followed my post to the letter and changed my diff fluid after the 500 mile break-in to remove any metal shavings developed on the break-in as there is no filter in the diff. My third diff has no whine at any speed after 33,000 additional miles...

Good Luck for those with new Diffs and yes the 500 mile break-in was a big ego tester and the looks were no fun , I got thru it by saying the increased fuel mileage average was great and watching/laughing at how many drivers do not know how to pass a slower car...

I hate to keep reading about the diff whine issue - GM/Pontiac never did anything about this issue as a Company and let the customer fend for themselves with their Dealership - something I will remember on my next purchase. The Best I can say is that if you do develop the problem , get your Dealership to make it right , then follow the break-in I describe above and your chances of the whine reappearing are much less likely...

Are we having Fun yet ???

I didn't even get a chance to break it in to see if it made a difference because the new diff. whined before I even left the dealership lot and got a chance to exceed 55mph. I know that GTO differentials can be quiet as mine had no whine whatsoever for the first 1000 miles and I religously followed the break-in process. So, go figure!

Luckily I realized that there had to be a break-in procedure. (whew!) I've kept a top speed of 65, except for once during that time. I was well over 65 for a short time.

I'll be swapping out the fluid ASAP, probably when the Pedder's stuff goes in, so...I'll let you guys know how it goes.

What is the number for the rear end TSB and is it for 05? Mine has the whine also and as long as its in te shop for te traction control problem I might as well show them this too.

Quote: Originally Posted by iroc89350... What is the number for the rear end TSB and is it for 05? Mine has the whine also and as long as its in te shop for te traction control problem I might as well show them this too.

There is no TSB (for any year GTO 04-06) to show anyone about rear differential problems. I don't know where this myth started, but it doesn't exist. I've got Dealerworld at my fingertips, no TSB!

There is in fact a PI (preliminary information) document used internal to the dealerships that advises us at a dealer level not to attempt repairs at the dealership itself, but to replace the unit as an assembly if a problem does in fact exist (dealer descretion).

My original diff had a very slight whine. Dealer agreed that it was a problem and ordered a new one. Second one sounded like CRAP. Sounded like pinion and bearings both going south. Absolutely awful. Second replacement sounds the same only much quieter. At least I am not afraid to drive the car. It is very noisy and much much worse than the orginal. My independant mechanic had a look and listen and said, "Holy crap, this thing is going to go away sooner or later". It is most likely a pinion depth/backlash issue, but it is really hard to know for sure without a teardown and some ink.

The best part is that the dealer contacted the zone rep andafter a test drive he says that the sound is normal. HAHAHAHAHAHAHA Im so pissed. I wish my original was back in the car.

I escalated to GM and talked to someone with a thick accent and they took the information and said they would get back to me. They stated that they had to contact the dealer and they could not find it in the system. (It is the highest volume GMC/Pontiac store in the nation!) I asked them for a 6 year 100M powertrain warranty (GMCCP) and a new hand assembled diff. FAT CHANCE I think.

It has been two weeks and I have no response. GM wonders why folks dont buy their stuff anymore. What a crock.

BTW, I drive this car like a little old man - mostly cause I am one. I am a car freak and don't beat on em one damn bit. Ive resotored a 27 Chev two door, a 66 Chev PU (still have it with 386 thou on the clock) and a 55 Thunderbird. I even had a firebreathing LT-5 powered ZR-1 Vette for a short time. I know automobiles better than nearly anybody I know. I am a bit of a purist - I mention this only for perspective. My Suburban with AWD (two full time differentials, and a transfer case) makes less (none) noise. ARGHHHHHH

The Goat is a great piece of work mind you, but the PR/point of sale support from the zones and factory folks SUCKS.

I am very dissapointed in the way this is being handled. NORMAL OC? BullS&*t!!!!

I hope someone from GM engineering reads this.... Fat chance on that too I would guess.

I hope the folks with the diff issue are in better straights now. I have not heard or read anything about a 500 mile 55mph limit. I think I blew that out in the first 500 feet when I left the lot along with the burn out on the way home. At 6,000 miles mine is very quiet. It is starting to develop a bit of drive line lag/slap. I am going to be getting the bearing thrust retainers checked (yeah, I know I did not use the correct term.) next service.

OldWolf99

Quote: Originally Posted by OldWolf99... I hope the folks with the diff issue are in better straights now. I have not heard or read anything about a 500 mile 55mph limit. I think I blew that out in the first 500 feet when I left the lot along with the burn out on the way home. At 6,000 miles mine is very quiet. It is starting to develop a bit of drive line lag/slap. I am going to be getting the bearing thrust retainers checked (yeah, I know I did not use the correct term.) next service. OldWolf99

The 500 mile/55MPH is in you owners manual. But, it doesn't mean anything. My original diff whined badly at 300 miles, never even got to complete the break in period. Took them 3 months to get a new differential. Now after 9000 miles on my second diff, its just starting to whine between 30-35. Not real bad, but noticeable compared to what it was. Its way better then it was with the original diff, so I'm not complaining. Oh, and GM doesn't make the rears, Dana does.

Have yet to get a diff that has made bad noises right from the service drive. going in again soon, wonder what their going to say about my 275 kumho's on back.

no whine here,but that should change to not going to happan with 3.91's and a spring tuning kit

Dealer is ordering the "good" dif for me today after reading this thread! THANKS for posting the part number. Stay tuned.

Quote: Originally Posted by IDNTWN2... Dealer is ordering the "good" dif for me today after reading this thread! THANKS for posting the part number. Stay tuned.

That's what it's all about.

Just got mine back yesterday with the new diff and updated guage cluster - No whine yet, so we'll see...

Question... what does the whine indicate? Im not sure if what Im hearing is the differential whining or not... What are the consequences of not getting it replaced? Thanks.

Bueller?

Quote: Originally Posted by Underoath... Question... what does the whine indicate? Im not sure if what Im hearing is the differential whining or not... What are the consequences of not getting it replaced? Thanks.

Usually the whine indicates a bad pinion angle, for lack of technical terminology. Sometimes the bearing in there can be the culprit, too.

You'll know it if you hear it. To me it sounds more like a howl, like a wolf howling or something. Sometimes it's barely audible and you really have to focus on it... other times, like in my case you could hear it over the radio at low volume.

As far as I know nothing will fail because of the whine. It's more of an annoyance than anything. Plenty of people have gone tens of thousands of miles with whining diffs and nothing has come about it. Even alot of aftermarket rear ends and gears will whine and chatter. It's the nature of the beast in some cases.

Quote: Originally Posted by Grave... I also told them about other common annoyance I've been having - the clunking sound that comes from the right/rear quarter panel area when going over bumps. I printed out a thread from here and gave it to them in order to help them pinpoint the problem, but they were unable to find it. The tech who worked on my car was gone for the day when I picked it up, so they said to bring it in tomorrow and I can show them exactly where the clunk is coming from... since I know exactly where.

On a side note... I took the GTO to the dealer for the second time to pinpoint the clunking noise coming from the right rear quarter panel area. The found a few weak welds around the inner wheel well area. So Monday I'm bringing it back in so the body shop can strengthen the welds a bit more.

The whine that is most typical is usuall caused by pinion depth and backlash being incorrectly set. The odd thing is that differentials typically are not noisy unless depth is REALLY out of whack. If the pinion is too deep, it will wear out itself and the ring prematurely. It should not make whining whirring noise at all.

I was just afraid they would tell me it was normal, and then the diff would grenade at 37,000 miles. How convenient that would be.

Quote: Originally Posted by ZUMin3K... I was just afraid they would tell me it was normal, and then the diff would grenade at 37,000 miles. How convenient that would be.

There seems to be a bunch of them out there, so they may decide to tell you that it is normal. It may not be harmful in the short term, but a whiney hiney is NEVER normal.

Quote: Originally Posted by Grave... On a side note... I took the GTO to the dealer for the second time to pinpoint the clunking noise coming from the right rear quarter panel area. The found a few weak welds around the inner wheel well area. So Monday I'm bringing it back in so the body shop can strengthen the welds a bit more.

Just a final update on this.

Got my GTO back last night. All the weak welds were strengthened. No more clunking noise when going over speed bumps!

Here is what they wrote on the invoice:

Quote: CUSTOMER STATES VEHICLE MAKES A POPPING NOISE IN THE REAR END WHEN DRIVING OVER BUMPS. FOUND REAR OUTER PANEL CAUSING THE POPPING NOISE FROM WHERE THE ORIGINAL GAS FILL DOOR WAS LOCATED. REPAIRED RIGHT OUTER PANEL FOR POPPING NOISE

Just thought this might help some of you out...