F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > 2012-2019 BMW 3 and 4-Series Forums > General F30 Sedan / F32 Coupe / F36 Gran Coupe Forum > differential fluid leak on 340
ARMA SPEED
Post Reply
 
Thread Tools Search this Thread
      11-26-2021, 08:49 PM   #1
khanmohammed
First Lieutenant
khanmohammed's Avatar
No_Country
149
Rep
375
Posts

Drives: BMW M4 CS
Join Date: Oct 2019
Location: IL

iTrader: (0)

differential fluid leak on 340

So I have been running xHp Stage 2 trans tune for the past few weeks, absolutely loving it. Took my car to the dealership today to get a brake screech issue looked at and they also found a differential fluid leak near the front. No idea what caused it, does the differential sit lower to the ground and more prone to get hit if go over a harsh bump? I'm guessing it was either that or something related to the line pressure increase on the transmission caused the leak.
Appreciate 0
      11-26-2021, 08:56 PM   #2
n55david
Check out my Youtube @n55david!
n55david's Avatar
1288
Rep
3,502
Posts

Drives: 2017 m240i, 2015 X3 x35i
Join Date: Aug 2018
Location: Michigan USA

iTrader: (0)

Garage List
2017 m240i xDrive  [0.00]
2015 X3 x35i  [0.00]
2015 335i xdrive  [0.00]
Quote:
Originally Posted by khanmohammed View Post
So I have been running xHp Stage 2 trans tune for the past few weeks, absolutely loving it. Took my car to the dealership today to get a brake screech issue looked at and they also found a differential fluid leak near the front. No idea what caused it, does the differential sit lower to the ground and more prone to get hit if go over a harsh bump? I'm guessing it was either that or something related to the line pressure increase on the transmission caused the leak.
transmission has nothing to do with front diff. just bad seal from the factory, the gasket is going bad. more common on the rear actually. I have to do my rear in the spring.
__________________
2017 m240i xDrive 10.99@122.86mph bootmod3 stage 2+ ots
2015 335i xDrive 10.95@124.99mph w/bm3 - SOLD
2015 X3 x35i pwg 12.96 catless w/bm3 stage 2 93 ots
IG: @n55david For pics and updates!
Youtube: @ n55david For videos or Racing etc
Appreciate 1
johnung4510.50
      11-27-2021, 05:31 PM   #3
khanmohammed
First Lieutenant
khanmohammed's Avatar
No_Country
149
Rep
375
Posts

Drives: BMW M4 CS
Join Date: Oct 2019
Location: IL

iTrader: (0)

Quote:
Originally Posted by Phantom10R View Post
Quote:
Originally Posted by khanmohammed View Post
So I have been running xHp Stage 2 trans tune for the past few weeks, absolutely loving it. Took my car to the dealership today to get a brake screech issue looked at and they also found a differential fluid leak near the front. No idea what caused it, does the differential sit lower to the ground and more prone to get hit if go over a harsh bump? I'm guessing it was either that or something related to the line pressure increase on the transmission caused the leak.
transmission has nothing to do with front diff. just bad seal from the factory, the gasket is going bad. more common on the rear actually. I have to do my rear in the spring.
Yep that's weird though I'm only at 17k miles, dealership didn't even know how to fix it so they reached out to corporate engineering team Lol
Appreciate 0
      11-27-2021, 07:10 PM   #4
njdangelo
Captain
njdangelo's Avatar
431
Rep
839
Posts

Drives: 2019 x5 50i
Join Date: Sep 2019
Location: CT

iTrader: (1)

Quote:
Originally Posted by khanmohammed View Post
Quote:
Originally Posted by Phantom10R View Post
Quote:
Originally Posted by khanmohammed View Post
So I have been running xHp Stage 2 trans tune for the past few weeks, absolutely loving it. Took my car to the dealership today to get a brake screech issue looked at and they also found a differential fluid leak near the front. No idea what caused it, does the differential sit lower to the ground and more prone to get hit if go over a harsh bump? I'm guessing it was either that or something related to the line pressure increase on the transmission caused the leak.
transmission has nothing to do with front diff. just bad seal from the factory, the gasket is going bad. more common on the rear actually. I have to do my rear in the spring.
Yep that's weird though I'm only at 17k miles, dealership didn't even know how to fix it so they reached out to corporate engineering team Lol
What do you mean the dealership didn't know how to fix a leaking differential? THAT'S weird. There's only a handful of places it could leak from and all of them have gaskets…..and you're not even under warranty because you modded your car so they could just tell you your diff is shot and you need a new one. What could "corporate engineering" possibly have to say to them?…are you sure they didn't say "we see your front diff is leaking but we also saw your tranny was tuned so we don't know if your diff is under warranty anymore. We have to call "corporate engineering" to see what they say". And you didn't hit anything with your diff. If you did, you would know immediately and without question…. Plus you'd have a ripped to shit under carriage cover and front bumper as the diff sits higher than the bottom of the bumper
__________________
2019 x5 50i - current
2016 340i THP stage 2 - gone but not forgotten.
Appreciate 0
      11-27-2021, 09:39 PM   #5
johnung
Major General
United_States
4511
Rep
5,377
Posts

Drives: 2015 BMW 335i x-Drive Auto
Join Date: Oct 2017
Location: New Jersey/Philadelphia

iTrader: (1)

Garage List
Quote:
Originally Posted by njdangelo View Post
Quote:
Originally Posted by khanmohammed View Post
Quote:
Originally Posted by Phantom10R View Post
Quote:
Originally Posted by khanmohammed View Post
So I have been running xHp Stage 2 trans tune for the past few weeks, absolutely loving it. Took my car to the dealership today to get a brake screech issue looked at and they also found a differential fluid leak near the front. No idea what caused it, does the differential sit lower to the ground and more prone to get hit if go over a harsh bump? I'm guessing it was either that or something related to the line pressure increase on the transmission caused the leak.
transmission has nothing to do with front diff. just bad seal from the factory, the gasket is going bad. more common on the rear actually. I have to do my rear in the spring.
Yep that's weird though I'm only at 17k miles, dealership didn't even know how to fix it so they reached out to corporate engineering team Lol
What do you mean the dealership didn't know how to fix a leaking differential? THAT'S weird. There's only a handful of places it could leak from and all of them have gaskets…..and you're not even under warranty because you modded your car so they could just tell you your diff is shot and you need a new one. What could "corporate engineering" possibly have to say to them?…are you sure they didn't say "we see your front diff is leaking but we also saw your tranny was tuned so we don't know if your diff is under warranty anymore. We have to call "corporate engineering" to see what they say". And you didn't hit anything with your diff. If you did, you would know immediately and without question…. Plus you'd have a ripped to shit under carriage cover and front bumper as the diff sits higher than the bottom of the bumper
It actually might not be that unusual that typical dealership mechanics don't have experience with an F30 rear differential. I found this to be the case when I bought a BMW M Performance LSD and looked for dealerships and independent shops to install it.

Differentials are pretty bulletproof until they get high mileage so mechanics who have replaced differentials have mostly done so on E-Series cars. Those differentials are much easier to work on. The driveshafts are attached with simple bolts. The F-Series driveshafts require special tools because they use a circlip that runs in a groove on the shaft.

My independent BMW shop mechanics were baffled when I brought them my LSD. They were BMW factory trained with decades of experience but the F-Series differential was a new design and it was the first one that they had gotten their hands on. It took them a couple of days to research and to obtain the special tools
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:00 AM.




f30post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST