Rear end Rebuilt --> What a mess!

[drilzzz]

1997 Mustang GT. I got my rear end done at a local shop who was sorta a family of a friend. I ended up paying $2050 for the below mentioned work.

Symptoms before work: LOUD humming noise coming from the back.

Work done: 2x rear tires, spider gears, 2x rear axle shafts, 2x axle shaft bearings, ring and pinions, traction lok rebuilt. The new gears are 3.73

After Work: Once I got the car back I realized the car was a bit "peppier". I drove it with a light for a couple days to allow ample time for meshing (spelling) and then went back to normal driving. The first day I got the car back I noticed a WHINING sound coming from the rear. It starts at about 25mph and goes all the way to about 40mph. The sound is only apparent when pressing on the gas pedal SLIGHTLY. I did some research on the net and went to another mechanic and both sources tell me that its from the ring and pinion set up. I went back to the shop where I had gotten the work done and he told me he used a new shem (spelling) on the pinion and he told me he used a FRPP ring and pinion (BS). They told me to drive it for a week and allow a break in period to see if the noise goes away. Additionally, this morning when I was ROLLING out of my driveway I heard 3 LOUD consecutive knocks coming from the rear.

What should I do? Is the whinning noise from a bed set up of the ring and pinion? What the heck could cause those loud knockings? I spent over 2 grand of my school loans to get this job done and the rear end still does not seem reliable or safe to me. I was told i was getting a two year warranty on everything and once i got the receipt there was nothing about a warranty. The guy who did the job told me he was not EAS certified and I was charged 90 dollars an hour. Any advice would be really really helpful. Thanks.

 

[ChillPhatCat]

That's a bit steep, but pricing depends a little on the parts used... expensive tires, hardy axles... good gear set and an expert install could get up that high legitimately.

If it was just wining I'd say let it break in a little, but with other noises you're hearing... I would be a little leary to call it normal post install symptoms. Have you asked the shop that did it about the knocking sound yet? If it goes south I'd say find a certified mechanic not related to this guy or his shop take a look at it. If they screwed up make them fix it and if they refuse, take them to small claims court, get your money back and have a real mechanic do it.

 

[drilzzz]

I have no idea what part brands he put in. I should of asked to seen all the parts before their placement but I don't have a second car and I though it would be insulting (stupid me). He said he put Yukon axles in but I haven't checked them yet... raining too much in Florida right now. The shop is closed but I will call first thing in the morning.

THe whining sounds just seems too loud to be normal and it only happens at a certain mph range and the knocking was today which is now the third day I've had it backs since the rebuilt. THanks for your reply.

 

[hotdog71]

WTF is with the Yukon axle, should be using Ford parts! what was up with the axle was it messed or something?

Gear whine is due to bad installation job period! There is no break in period for gear whine!! they must have used the wrong number of shim spacers or screwed up the crush sleeve pressure..

 

[Flghtmstr1]

It sounds like the shop screwed something up. Gears should not whine, period. If they do, take it back and make them fix it.

Why did you have them replace the axles? Did you upgrade to 31 spline units?

Also, FYI, there's no "break-in period" required for gears. When you get this sorted out, feel free to romp on them from day 1.

 

[drilzzz]

HotDo71- I would love some original Ford axles but they told me the Yukons are suppose to be 20% stronger. The old axles got worn down because I didn't have the money to fix my bearings. Im new to the modding scene to I took his word for it. First Mustang... had it for a while but I finally got some money through school to fix some things while increasing reliability/ performance. I went to Performance Revolution this morning (local shop in davie, fl), the guys down there are great and had no problem in educating me a bit and also letting me know that the other shop did a horrible job. They told me the guy should of used the old shim but he used a new one instead. I took the car back to the shop and had the owner ride with me and he heard the noise and agreed that the noise is way too loud. He blames it on the mechanic. So the car will be there overnight in order for them to get that spacing right. Should I be concerned about the ring and pinion that were already placed in there? Should i demand them to be replaced again?


Flghtmstr1- thanks for the words. Break in period sounded like BS. No upgrade on the spline. I should of asked about that.

 

[kuwait]

i have two mustangs that i did gear install on them several times , there is no break in period for the gear whine , they would only get worse with time(a year or so , not a fast process) , if the whine is really loud and annoys you , go to the shop and ask them to reinstall them , my 1997 rear end was a nightmare to get it not to whine (torn the rear end 6 times and had a down time of 3 weeks).

if you drive the car briefly or even stomp on it when gears are whining it wont make a difference if its not for extended amount of times (driving it for weeks) you should be fine , ask for a reinstall and if it doesn't whine , enjoy the gears , gears aren't all that sensitive you wont need to replace them

 

[drilzzz]

Kuwait- thanks for eliminating that concern. I got the car back Friday and drove it total of about 30 miles with the whining and about 10 miles after hearing the first knock sounds. I chirped the tires once though today before i dropped it off... it was by accident

 

[Kilgore Trout]

its normal to have to go back in and re shim do not accept whine you paid for premium service that is a bit much

 

[Kilgore Trout]

knock was probably just the suspension

 

[drilzzz]

thank kilgor trout.

They took the car yesterday and told me the car wont be ready today and it should be done tomorrow (sigh). They have to take the car to another shop in order for it to get calibrated. Should take about 5 hours of labor. The shop owner is allowing this mechanic to take the car to another shop to get the work done.

 

[sbelyo]

My labor costs were $350 I think and that included the diff rebuild.
The parts I used were all Ford

FMS-M-4209-G355A RING AND PINION 8.8" 3.55 $149.95

FMS-M-4210-B 8.8" RING & PINION INSTALL KIT $82.95

FMS-M-4700-C 8.8 TRAC LOCK KIT $104.95

RPO-01301 MAX GEAR OIL 75W140 $35.90
so it was about $750 in all

Over 2 G's sounds a little high to me as well

 

[drilzzz]

I paid a lot. I could of saved at least 500 by going to another shop. I got the car back today and it drives a lot quieter. I don't feel like there has been a major difference with the gears though. I might take it to another shop to verify the 3.73 gears. I was hoping for a bit more pep. I'm just happy the car is back on the road.

 

[Cherry99GTvert]

Man hell would freeze over before id pay 2 grand for a dif overhaul thats just rediculous, you shouldve shopped around there are too many shade tree mechanics or wanna be mechanics out there that will say anything to get you to pay outrageous fees ive worked at plenty of shops and have seen it too many times.