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4.10 noise issues (not whining)

4K views 45 replies 11 participants last post by  Beagle1 
#1 ·
Like so many out there I have had 4.10 ring and pinion gears installed. When picking up the car I cringed as I drove off waiting for the dreaded gear whine to start, but to my surprise everything sounded good all the way up to 80mph, which is as about as fast as I would ever drive. I do have a different noise that is causing me some concern and need some advice from you all out there that have had 4.10 gears installed also. I am hearing kind of a rushing noise from the rear end at speeds of 30mph and over. Is this normal for this gear ratio as there is more teeth meshing or is this something I should be concerned about. It is only noticable when driving beside a retaining wall or something similar where the noise can reflect back. Is there any experts in this area out there that can give me some advice.:headscratch:
 
#2 ·
I have absolutely no noise from my 4.10. Well nothing that wasn't there with the 3.55's
 
#5 ·
I'm sure I have over a 1000 miles on it by now. I think I'll make an appointment to get it in next week. Does anyone have an idea what could be making this type of noise, perhaps a bearing? I had the bearings replaced when they did the install???? It would help to have some info on this when I take it in so I can at least appear to know what I'm talking about.

Thanks all for your help.
 
#7 ·
I live about 5 miles out of the city. After I picked up my car, I basically just drove it home, some city stop and go driving and then some high-way driving but not real fast (50mph or so). I drove it back and forth to work in the city like this for about two weeks before I really tried to put the power down through all the gears. I can't imagine this kind of driving could of harmed the rear end.
 
#9 ·
Doubful... However, the general rule of thumb is you drive for 10-15 mins the first time and then cool completely. Then for a half-hour and cool completely again. This gives both the bearings and the gear face a chance to break in without the fluid getting superheated.
 
#8 ·
I had a noise like that too, but I concluded that it was whining. When I would accelerate, it would sound like, 'WHHHHUUUURRRRRRR" and when I let off the gas it would sound like, 'WHEEEEEEEEEEEEEEEEEE'. There were also mild clunky noises back there too. Needless to say, I got some new gears. You should take yours back in and see what they can do.
 
#17 ·
Well, I haven't seen my car in over two weeks... but before that, they were excellent. No noise whatsoever.

p.s. It looks like the blue beast will be coming home tomorrow night (after a little side trip to the track). :gringreen
 
#30 ·
cman, I have the exact same sound. I had 4.10 gears installed and they sounded fine for about a week and then developed this sound. It isn't gear whine, more like rushing air or even a water rushing through pipes kind of sound. I hear it above about 30 mph, and like you said is best heard driving by a wall or something, although you can also hear it pretty well with the windows up.

I took the car in and they said it was the bearings. They replaced all the bearings and reset the rear end. Car was fine again for about a week and then I started hearing the same sound again. I am going to be taking it back in soon to have them check it out, I will let you know what I find out. Let me know if you get any answers yourself. It is indeed the bearings though, I just can't figure out why they start going bad.
 
#32 ·
The installer said mileage didn't really matter, what mattered is getting in three heat cycles to break them in. I stayed under 70, did about five heat cycles of 20-30 miles each, with plenty of cool down in between. I had to merge on to the highway for each of these, but I took it as easy as possible. And I really waited about 300 miles before getting on it hard at all, even then I really wasn't driving it that hard, just stabbing the throttle a little more.
 
#34 ·
Thanks for your feedback. I went to the place that installed the gears and had the service manager come for a ride with me. He admits to hearing the noise (that's half the battle) and I have it booked in next week for them to look at it. I put the car up on jackstands in my garage and ran it just above idle in fith gear, there is no question that the noise is coming from the diff. I'm sorry to say, in a way I'm gad I'm not the only one with this issue and I hope you good luck with the next attemp to fix your car.
 
#35 ·
sdwndr, Have you had any luck yet? I have my car in right now, and it's been in for Two days. I think they are either putting it off and hoping I'll go away, or they can't figure out what is wrong with it. I hope to know more tomorrow.

To anyone else out there that is thinking about any kind of a rear gear change, think long and hard. Unless you have a totally reliable shop to do the work, I would suggest spending your $800 - $1000 on something else. it seems the rear gear thing is a crap shoot on whether you get a good install. Thankfully not all mods are this tempermental. This is just coming from what I have gone through so far and wishing the idea never popped into my head.:frustrated:
 
#37 ·
cman-
My car is going in hopefully this Friday to (again) have all new bearings installed in the rear end. His only possible explanation was that they missed some metal shavings when they did the work the first time. Other than that, he has no idea what could be causing the sound.

After I had the bearings replaced the first time, I first noticed the sound again after accelerating pretty hard. Even though the gears weren't changed, simply reset after having the bearings replaced, does anyone know if I need to follow the usual break-in procedure?
 
#46 ·
I wonder how people are installing these gear sets to have so many issues?

Improper tools for measuring? Improper training? Reusing preloaded bearings & races? Using new bearings in old races? Not a proper stock of side shims on hand?

Gear sets are matched when produced. They have plenty of stampings and paint pen written numbers on them to give direction on shimming, backlash, etc. Then there is the last word, the gear marking compound.

You have to have a good supply of shims on hand and a good depth gauge for a gear change to come out with minimal noise and long term success. New crush sleeve and an in-lb beam torque wrench to check pinion preload.

I will openly admit I have had plenty of failed attempts at gear set changes in my day, but I learned from it. Fortunately not at anyone else's expense. And I had a great teacher in a guy 22 years my senior teaching me properly. 8.8" rears are a PIA compared to an old 9". To do an 8.8 correctly can involve multiple assembly and disassembly attempts to measure and remeasure. A 9" could be built and checked once on the bench and installed.
 
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