2007 BMW 318i - REAR DIFFERENTIAL - Petrol & diesel the same

2007 BMW 318i - REAR DIFFERENTIAL - Petrol & diesel the same

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eddiebacon

Original Poster:

5 posts

58 months

Wednesday 15th January 2020
quotequote all
The rear differential on my 2007 BMW 318i petrol has gone and im struggling to find a replacement for a reasonable price around my area in Nothampton UK.
There are a quite a few diesel ones available so i was wondering if they are the same as the petrol differentials?
If anyone could help would be greatly appreciated.

BFleming

3,764 posts

150 months

Wednesday 15th January 2020
quotequote all
eddiebacon said:
The rear differential on my 2007 BMW 318i petrol has gone and im struggling to find a replacement for a reasonable price around my area in Nothampton UK.
There are a quite a few diesel ones available so i was wondering if they are the same as the petrol differentials?
If anyone could help would be greatly appreciated.
No, they're different. Also the 318i has different differentials depending on whether manual or automatic. The manual has a final drive ratio of 1:3.23, whereas the automatic is 1:3.91. The part numbers are as follows:
Manual:
33107524318

Automatic:
33107524325
or
33107524326

The good thing (clutching at straws here) is that the differentials were shared between all 3 series of your vintage - so E90 (saloon), E91 (Touring), E92 (coupe) and E93 (cabrio), as well as some E87 1 series. Hopefully this helps you out a little. My advice is to keep the same ratio as your current diff. Some ebay sellers seem incapable of listing a part number or final drive ratio correctly, so maybe target the specialist BMW breakers.

Mattiebmw

183 posts

125 months

Wednesday 15th January 2020
quotequote all
I know a guy who will be able to sort it for you, however he’s based in South Yorkshire. I was going to get the one on my 1 series done but I part exed it instead. Let me know if you want me to dig his number out.

eddiebacon

Original Poster:

5 posts

58 months

Wednesday 15th January 2020
quotequote all
BFleming said:
No, they're different. Also the 318i has different differentials depending on whether manual or automatic. The manual has a final drive ratio of 1:3.23, whereas the automatic is 1:3.91. The part numbers are as follows:
Manual:
33107524318

Automatic:
33107524325
or
33107524326

The good thing (clutching at straws here) is that the differentials were shared between all 3 series of your vintage - so E90 (saloon), E91 (Touring), E92 (coupe) and E93 (cabrio), as well as some E87 1 series. Hopefully this helps you out a little. My advice is to keep the same ratio as your current diff. Some ebay sellers seem incapable of listing a part number or final drive ratio correctly, so maybe target the specialist BMW breakers.
Thank you very much this really helps

Touring442

3,096 posts

216 months

Wednesday 15th January 2020
quotequote all
eddiebacon said:
The rear differential on my 2007 BMW 318i petrol has gone and im struggling to find a replacement for a reasonable price around my area in Nothampton UK.
There are a quite a few diesel ones available so i was wondering if they are the same as the petrol differentials?
If anyone could help would be greatly appreciated.
I have one.

Petrols are small case (168) and vary from 3.23, 3.38, 3.46, 3.64, 3.73 and 3.71. Yours is most likely a 3.23 or 3.38, got a really nice one here. I can fit it as well for a modest fee. PM me if you like.

E90 diesels are all the bigger case 188 so won't fit.

Edited by Touring442 on Wednesday 15th January 14:57

Paul06

1 posts

15 months

Monday 14th August 2023
quotequote all
Hi I have the same problem does it matter what engine size the diff has come from mine is the e90 318i 2007 petrol 1995cc

The Conflated Outlier

125 posts

20 months

Wednesday 16th August 2023
quotequote all
These are the small case 168 diff with seven bolts holding the rear cover on.

A 2007 318i manual with the N46 engine will have a 3.23 ratio diff now becoming hard to find in other than scrap condition. The ratio and part number are on a white barcode sticker on top of the diff that is almost impossible to see when fitted - you can possibly get a mirror in there or get in and carefully peel it off. The part number for those is 7525108 0r more commonly 7524318.

Later 318i's with the N43 engine have a more common 3.38 diff. Physically identical it will bolt in and work perfectly. It's only when you get into 2008 onwards cars with the auto stop start (with the button to switch it off) that you can't fit the wrong ratio diff as the ABS and gearbox speed sensor will detect it and put the car into limp home mode. The number on these is 7524319 or 7524320. Most 320i manuals have a 3.45.

Bear in mind the BMW part numbers on Realoem/BMWfans is often one digit out to what's on the sticker of your old unit - that's the factory replacement number.

You also have a choice of 3.45 (320i) and 3.64 as fitted to 320i Coupes - that will make the car noticeably more lively.

The problem is finding a genuinely good diff and most breakers haven't got a clue. The pinion bearings fail (that's what the noise is) and later ones are worse due to a change of bearing supplier from INA/FAG to Koyo. When you turn the propshaft flange it should feel smooth - if it sounds noisy then it's knackered.

I normally have a couple knocking about but good ones are rare atm. As a short term thing you can get the old oil out via as suction pump and refill it with EP140. It will be a bit quieter - unless it's really howling.

PM me if you like.