Bell Housing / Autobox Swap

Tue Jul 07, 2009 7:31 pm

When my 4hp22 box went pare shaped, I had one hell of a task to find one for my 316, M10 , 1986 E-30.

What I did find out was the actual "gear box" was the same from a 325 but the bell housing was obviously different, the final drive making all the difference in the end.

Has anyone done or know if you can take the bell housing from a 325 off and replace it with the one from the M10 engine ?

Would this mean in theory that I could have a "switchable " 316 ??

Cheers, Mart.

Tue Jul 07, 2009 11:57 pm

BMW gearboxes and bell housings are all one casting, I'm afraid.

Wed Jul 08, 2009 5:23 pm

I bust a bellhousing not so long ago and was able to swop it easily
It just unbolts if you are very careful!!

Wed Jul 08, 2009 5:25 pm

Forgot to say...it was also an auto
Good luck

Wed Jul 08, 2009 6:16 pm

Brianmoooore that ain't true.

Bell housing can be taken apart on the ZF4HP22 auto's, but if the bell house fits all of the auto's out there i can't answer, but it takes you 5 minutes to try, just remember to unscrew the bell house and not the oil pump ;)
Atleast my box i can take the bell housing off, i know there is auto's out there where you can't do that.

Wed Jul 08, 2009 9:31 pm

E30cabalan wrote:I bust a bellhousing not so long ago and was able to swop it easily
It just unbolts if you are very careful!!

Nice to hear this, I thought I was correct , being a toolmaker I look to why BMW should cast so many variations when a simple interchange would do.

The jury is not %100 just yet , but Im working on it .

Cheers, Mart.

Thu Jul 09, 2009 1:10 am

ProToZyKo wrote:Brianmoooore that ain't true.

Bell housing can be taken apart on the ZF4HP22 auto's, but if the bell house fits all of the auto's out there i can't answer, but it takes you 5 minutes to try, just remember to unscrew the bell house and not the oil pump ;)
Atleast my box i can take the bell housing off, i know there is auto's out there where you can't do that.

Just been out to the workshop to have a look at one - and you're right! I've never noticed that join before! All one piece casing on E34 and E36 auto boxes though.

Thu Jul 09, 2009 6:09 pm

So going on the information so far, and having looked at the part numbers for the box and oil pump (which are the same for the 325/316) I believe it is reasonable to assume that I could take a 325 switchable box, change out the bell-housings, and fit it to my M10 block.

Now comes the good bit, how does the wiring for the box come into play?

Mart.