Help need advice - Installing new auto tranny with 4 bolt output flange
 

We have an 89 BMW 325i that has auto driveshaft with 3 bolt orientation on front driveshaft. The new/rebuilt 4 HP22 automatic tranny we acquired from Craigslist has a 4 bolt output flange on it.

Ordered a 30mm thin wall deep socket to facilitate swapping the output shafts on back of tranny but will be awhile until I get the socket.

Getting conflicting info on whether the 3-bolt and 4-bolt flanges can be swapped from one automatic tranny to another.

What kind of year/model car used the 4 bolt front flange? Thinking about just trying to buy a front piece auto driveshaft/guibo that has the 4 bolt setup so we don't have to change output shafts, but so far having trouble locating one.

Would really appreciate any advice/recommendations.
Thanks much.
--Scott

I'm pretty sure that the driveshaft needs to be changed. They used a few different driveshafts on these cars. What flange is on the transmission you pulled out? The stock transmission SHOULD have a four bolt flange. What's the VIN off your car? That would help figuring this out too.

The car's VIN is WBAAB239K8848346 and its build date is 11/88.
We bought a 4 HP22 auto tranny from Craigslist and the seller did not know what year/model car it came from but I would guess 1986 because I've heard from a couple places that is the only year that used a four bolt output flange on an auto tranny. All of the trannys we've ever seen (E30 or E36) use the 3 bolt output flange. This is the first one I've run across that has the 4 bolt configuration.
I did some calling around and it looks like a used four bolt driveshaft would be >$200 so that's not really an option.

If your old driveshaft is the same length or longer, you can take it to a driveline shop and swap out or install the 4 bolt flange.

Or at the front universal joint, you might be able to install the 4 bolt flange yourself if no driveshaft mods are needed. Compare the length of both to confirm.

According to the VIN, your would have come with a three bolt flange from the factory. I'm not sure what's involved with swapping out the flange, but 11/88 does put it on the edge of a production change.