Leaking diff. At pinion seal, after replacing Throwout Bearing
 

Hey guys, I want to share my story to see if anyone else has had the same issues.

So about 1 year ago I had my final drive changed to an MFactory 4.67, loved it by the way. No problems for awhile then I started to get shutters from first gear engagement. Did my research and diagnosed the problem to a failing throwout bearing as it was making the grinding sound when clutch was pressed in. So I replaced everything, new throwout bearing, pivot arm, even got a new exedy stage 1, since I was opening her up. Car is a 2013 74k miles. During the install my shop pointed out that my diff was leaking at the pinion seal, driveshaft and diff connection. So I changed the diff fluid to see if it was an immediate issue. Well one week later it’s pouring out and burning on my exhaust, noticeable smell. So I sent the car back to the shop, after 1 month of hearing nothing I finally get word that my ring and pinion have prematurely worn, and they need to be replaced. Shop says they think the leak started after the wearing to the ring and pinion. So my question is, do u think the MFactory parts are the problem or could I have had a small leak at the pinion seal that caused the ring and pinion to wear from low fluid in the diff. Any input would be appreciated Thanks

I would expect that the install of the final drive created the problem. Could've been too tight (to much preload causing premature bearing failure), could've had a bad gear mesh (gears pressed too hard against each other or too much slop). If you kept the same differential, then the only other real explanation would be that there is metal shavings tearing up the seals which would be caused by poor installation.

I did my own final drive and differential change and know how tedious the process can be to get things to align perfectly while keeping preload where it needs to be for new/used bearings.

You won't know for sure until you tear it open!

Just adding some supplemental info as to the difference in final-drive ratios (since I asked the question to myself, clicked :search:, and resulted this handy chart).

https://jackstransmissions.com/blogs...ar-ratio-chart

Well the same shop is installing the new ring and pinion. They claim the premature wear is what caused the leak from cheap parts. So I’m going to demand they change the diff fluid after 500 miles and see if it’s got a lot of shavings again. That would mean it was installed incorrectly again right?

I suppose it's possible the MFactory gears wear oddly.. I've never used them or known anyone that has personally. "Premature wear" backs up what I said about it potentially being installed incorrectly. How many miles did you get on the gears before the pinion started leaking? Are you installing another MFactory gear set?

I would always expect some fine shavings coming out of the differential fluid. Nothing large for sure. I think it would be a decent idea to have them check up on it somewhere between 500-1500 miles after initial install.

something is out of alignment, putting stress on the seal as well as the internals to the diff.

Yeah I’m gave them the same 4.67 ring and pinion. I’m not certain when the leak actually started, but I only put 9k on the car since they were originally installed. Hoping for a better result next time.

9k? That's definitely installation error!