I've got a 9" with 4.11s, 31 spline axles, and a TruTrac posi. I have two questions.

1) The rear has always been loud. Especially in 5th and 6th out on the highway from 55-70 mph or so. The whine is noticeable driving around town at around 40mph as well. It's got maybe 2000 miles on it, and was broken in properly. It is a professionally built 3rd member from DLS. I showed some fellow gearheads a picture of the gearset that I took when the rear arrived at my house. The paint was still on the gears and showed the pattern. They said it looked good, but may very well be noisy due to the fact that it's 4.11s, and the gears appear to be a fairly straight cut. Whereas many gearsets you see have a noticeable curve to the teeth on the ring gear, these seem to be straighter, at least to me. Is there anything I can do? I sent the 3rd member back to DLS to be inspected and have the pinion seal replaced and the pinion yoke swapped otu to a 1350 series unit. When I got it back it was the quietest it's been, but it got a little louder as I put some miles on it and then seemed to settle down and not get any louder. Then it got louder after a trip to the track. It's roughly as loud now as it was before sending it off to have it inspected. I was only pulling 1.8 60's getting the left front up on DRs. I plan on throwing quite a bit more power and harder launches with better suspension and slicks. Is there anything I can do? I've read several threads about noisy 4.11s, but many people have gotten rear ends from this sponsor and say they are very quiet. All the angles have been set, checked, reset and checked again. I also have a new driveshaft that's high speed balanced. This is part of the reason I went with a 9". I didn't hear very many stories of gear noise issues, or them getting louder after running at the track, where I heard a good number of 12-bolt owners complain of gear noise.

2) I put the rear in, and within a month or so the pinion started leaking. No track time, but some "spirited" street driving shall we say. I also had a vibration from a shitty stock shaft. I double checked and reset all the angles, and figured the vibration took the pinion seal. I had the seal replaced when I got the 3rd member checked and the pinion yoke swapped. I had no issues, and after getting the rear put back together I installed the new driveshaft. After a trip to the track I now have a leaky pinion seal again. Why the hell would my rear be eating up pinion seals??? Here's the kicker... I don't understand it, but it only seems to leak when it's sitting. There is no gear oil being flung all over the exhaust, underbody or T/A. It just sits and leaks when it's sitting there. It seems to do it moreso after running it hard.

I love being able to bolt stickies on and do some hard clutch drops and yank the fronts without worrying about grenading my rear end. However, this is a street driven car. It's no fun not to be able to enjoy it. It sounds like a POS going down the road from gear whine, and I have to constantly monitor the fluid level. That is it's own PITA. The T/A mount is in the way of the fill plug so it's usually a drain and refill operation to make sure it's full. I spent alot of money on this rear end...too much IMHO to be having problems. It's almost to the point I'm wishing I would've stuck with my stock rear. Puhleeeeeze help! Someone has got to have some ideas for me. I can live with a little bit of gear noise, but when I've literally had someone ask me what kind of supercharger I have because they heard the gear noise, that's a bit much.

TIA,
Jason

 

My pinion seal started leaking the day I got my rear installed.

 

Hmmmmm...those sound like problems usually reserved for the aftermarket 12-bolt camp. Almost sounds like you have a housing distortion issue of some sort...I don't know what to tell you other than that sucks *** big time.

 

I recomend another inspection by dropping out the center section and checking the oil. It's possible there was some left over contamination in the housing and that will cause a gear noise. I went through and 100% inspected your center section and it was in perfect running order. The only thing I found was that the backlash did open up to .010 but that should have not caused any noise. As for the seal, check and make sure your vent is not blocked. The air warming up and expanding inside the axle needs to vent or it will blow out seals.

 

I checked the vent when I drained and replaced the fluid after 300 miles.The pinion seal still leaks and I have had a whine since day one from 50mph and up.

 

Will do Scott. I'm over in Iraq right now, but I'm trying to get everything lined up for a big round of modding when I get back. I remember you saying that about the backlash opening up. I don't know if this makes any difference but here's what I've done.
- The vent tube that came with my housing has a piece of vacuum line attached to it that makes a fairly large arc around the sway bar and I end it inside one of the big cylindrical pieces of steel that the T/A mount bolts to. I have checked it, and it is not blocked.
- In June when before I reinstalled the center section I cleaned the hell out of that housing. I pulled the axles all the way out and cleaned inside the axle tubes the same way I would a gun barrel. I used rags sprayed with brake cleaner and kept pushing them through with a broom handle until they came out clean. Then I moved to the pumpkin area of the housing. I stuffed a large rag in each axle tube to keep anything from getting up in there. I left the drain plug out and began hosing that thing out mercilessly. Once I was satisfied with the main part of it I turned my attention to the bottom where everything seemed to collect. Once it was all done, I made one last wipe down with lint free rags. Pretty much right after that I reassembled everything. I cleaned up the center section as best I could. Maybe I missed something there.

I really hope I can get this fixed, becuase it is so damn frustrating.

Thanks Scott

Jason

 

Jay, you may also want to apoxy a magnet inside the housing. Let me know what you find when you get back in the states.

 

Will do. Too bad I accidentally broke the one out of my 10-bolt...LOL I'll be sure to let you know. She's going down for a cam, finishing out the bolt ons and most likely a shot so it'll be the opportune time to give the rear a good once over.

Thanks again Scott! Outstanding customer support as usual.