I've got a 9" in my car that I installed about a year ago. I've put around 2000 miles on it at best.
- Moser Housing
- 4.11 Gears (Brand Unknown)
- Detroit TrueTrac Diff
- 31 Spline Moser Axles
I also have poly/rod end combo LCAs and PHR as well as a Spohn body mount T/A. I understand that these will telegraph more noise into the cabin, but I honestly believe that what I have is excessive.

Issue 1:
Since it's been installed I've had a whine. There are several members with the same setup that highly praise it's quiet operation. My noise has gotten somewhat louder over the last year. It's downright uncomfortable to drive. Even with radio on, tops off and cutout open I can hear it. After about 1000 miles the center section was sent back to the builder for a new pinion seal and to have a 1350 series yoke installed. Both when new and after the yoke swap the rear was returned with the marking paint on the gearset. Several people have looked at the gear setup and said it looks fine. I'm no rear end expert, but to me it looked good. The whine/howl starts at about 30mph and only gets more intense as speed increases. The volume seems to peak around 60-65 then goes away just a little bit. However, noise is there from around 30 to as high as I care to take the speedometer.

Given that people have said the pattern looks good, I'm pretty convinced I've just got a bad set of gears. A friend of a friend asked to go for a ride in my car. Supposedly he knows rear ends. He commented that the setup sounds wrong. I defended the setup until the cows came home... to the point of arguing with the guy. Like I said, I'm leaning toward a defective set of gears.

Issue 2:
The bastard keeps leaking. First it was just a pinion seal, now it looks like possibly the pinion seal and/or where the pinion support bolts to the case. The vent tube is not blocked. Pinion angle is 100% correct, and I have no vibrations, at least not at any resonable speed... By reasonable speed, I mean speeds that one would normally drive at. Since the rear end has gone in it has seen just north of 150mph one time. There was a very faint vibration, but nothing major. My driveshaft is a PST aluminum if that makes any difference.

It's no secret as to how much these damn hunks of metal for our cars cost. I'm to the point of putting a f**king 10 bolt back in it and forgetting the whole damn mess. But I figured I'd give it one last try.

I have PMed the builder of the 3rd member twice in the last few weeks. I understand that the season is spooling up and everyone is busy, but I've recieved no reply. Therefore I'm now seeking someone competent in gear setup to install new gears (and bearings if needs be)... I guess just basically go through the 3rd member and make it like new, and hopefully quieter. Does anybody know of any sponsors who do gear installs?

Any help would be greatly appreciated. So if you know anyone that is versed in gear setup (preferably in easter New Mexico or in Texas) that you would trust hook me up. Honestly, this is the last go before I give up on this PITA.

 

BTW... Would it help if I were to make an in-car vid so the noise could be heard?

 

That much noise over that much range is probably bad gears caused by a bad set up. Get new gears and get it set up right.

 

New Gears Please!

I have run into this problem with a brand new set of 3.50 gears before. Did not matter how I set them up, they were loud. I tried backing down the lash a little and moving the pinion fore and aft a few thousandths, but to no avail. The pattern was beautiful though. Just bad gears. That is a very frustraiting problem. I got a different set and installed them and they were silent. I am skilled at setting up gears so I feel confident in my work. I learned from the best differential man I know.

Once in a while you will see a bad set. I hate it when that happens. BTW, a set that starts quiet, and then gradually gets louder, and eventually to the point of "Get me out of here!" is often caused by improper breakin. You should really take it easy the first 50 miles and then let them cool. Then drive nice for at least a hundred. Just don't go to the drags the day you put them in. Unless it's a race only car that you don't care if it's loud...

As far as leaking there, just replace the o-ring inside the pinion support. unbolt it from the third member. Thats so easy anyone can do it... Check out how the pinion bearings feel while you have that out. Just turn the pinion in the pinion support with the assembly out of the third member. It should feel smooth and take only slight effort to turn it. A lot like front wheel bearings with just the rotor on.

Also, a bad yoke swap job where the guy has no regard for what happens to the crush sleeve can cause issues as well. If the guy makes the bearings too tight, they might burn up and make a lot of noise. If the guy makes them too loose the pinion will side load and cause an otherwise nicely set up ring and pinion to have abnormal contact pattern. Any time you replace that yoke, you need a new crush sleeve. I don't like those so I use a solid spacer. I just add or subtract shims until you get a good feeling pinion. Should feel a lot like a good front wheel bearing on the older cars with tapered rollers. Usually you can mic the old sleeve you took out and add a few thousandths and be in the ballpark.

The 9 inch is a good diff. Just get the trouble sorted out. 10 bolts are even harder to work with.

If you are shopping for gears I would consider Ford Racing. I haven't seen too many of them have problems.

 

Thank you both for your input.

FWIW during the yoke swap a solid spacer was installed instead of a crush sleeve. Also here's what I did for my break in.
- I ran the car on jackstands idling in gear for about 15-20 minutes. Then let it cool. I repeated this a couple times.
- I babied the car for about 200 miles.

Regardless I understand what you're saying. As for my break in procedure, I always take what a manufacturer or an expert tells me and try to exceed that by at least 10% or so.

I'll definitely check out Ford Racing gears. I think what I'll do is pull everything down and inspect it as best I can, then take it somewhere for an install.

Thanks again!
Jason

 

wow! I found this thread to be very informative. thanks guys. hope this thread keeps getting added to.



fuerzaws6

 

Did you ever get this to seal up Mine is leaking after 2 pinion seals as well. The vent tube is fine. Did they make different size of yokes that take different seals. We were gonna mic it tonight but didnt get it pulled out. This is annoying.

 

When you have a leaking pinion seal, check the mating surface on the yoke. Mine had some machining grooves that shouldn't have been there and that's why it was leaking. A scratch or gouge could do the same thing. The seal surface should be very smooth all the way around.

 

Gears not setup right.

 

Anyone but me notice that this thread is almost 2 yrs old? 20 mos to be exact.

 

Yea, it's an old one..

I had a leak in my Moser Housing, turned out to be a seeping leak from the Housing Drain Plug. A little Teflon Tape fixed that.

 

Yea I was searching the topic last night and didnt wanna make a new post when there was the exact same thing in a post already. Im pretty sure the gears are set up right no whine or any problems like that. Im gonna try another new seal I guess.

 

the gears were installed improperly (or at least not correctly) judging by the noise. new gears will probably resolve the situation. dont go cheap on gears go for quality and more importiantly go for a better installer or do it yourself.

 

They are new richmond gears and I broke them in according to manual.

 

The proof is in the sound, not the pattern. It's entirely possible to have a good looking pattern that's noisy. Ask me how I know. I had my rearend guy set my gears 3 times before it was right (he's a pro). He told me that often you have to try several times to eliminate the noise and on occasion with some gear sets, you just can't. It's pain to yank it out two or three times but it's really worth it to not hear that whine every time you get in your car.