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Premium Member
320 Posts
Discussion Starter #1
I struggled for 2 days last weekend trying to get my rebuilt transmission installed into my 67 Duetto.
Previously, I had installed my 1600 engine (an AR00536 engine), so I was on my back underneath the car lifting it.
Around here, our gyms are closed. So this was my workout opportunity I guess.

I could only get it close enough to insert 2 extra long bolt into the upper bolt holes.
By doing that, I knew I had the orientation correct. But I still couldn't get it to slide all the way up to the engine.
That's when I noticed the studs off the back of the engine didn't line up to the holes on the bellhousing.
That bellhousing was NEVER going to mate to the engine.

Pulled it back out and removed the bellhousing from the rest of the transmission.

Without the weight of the rest of the transmission, it was easy to crawl back under the car with just the bellhousing and confirm - the holes didn't line up with the engine studs!

So, I had another bellhousing and I compared them. Sure enough, the holes along the driver's side were definately located in different positions.

Odd thing is, both bell housing have the same casting number - 10500 13 103 03
However, they were made by different manufacturers.
The one that doesn't fit to my 1600 was made by SIMI.
The one that fits was made by FGR.

I can understand if the SIMI bellhousing was made for a 750. Those engines and transmission were significantly different than the following 101 and 105 parts.
But I wouldn't have expected a 105 casting number to have been assigned to a part back when 750's were being made.

In any case, I have the FGR bell housing on the transmission now and it's all installed in the Duetto. It goes together pretty easiliy when the holes line up with the studs.

Here's the 2 bellhousings (FGR on the left - SIMI on the right). [Sorry - I cut off part of it in the photo but I was pretty tired and frustrated at that point]


Here's the casting numbers (FGR on the left - SIMI on the right)

Here's a tracing of the outline and the bolt holes

and a closeup of the outline and bolt holes on the right side


279 Posts
I am going to suggest that the Simi bell housings has become distorted- how who knows? I just checked my original 105 series 64 Giulia Sprint GT bell housing and it is the Simi!. Same part number too.
Knowing what others have said about fitting the gearbox back in with the engine in place and the difficulties in lining up the bolts, how did it go once you identified the problem?. I was wondering if the bell housing could be fitted first then the gearbox after sort of break in down into smaller segments if you will? Maybe not enough room to put the bolts in?.

Premium Member
320 Posts
Discussion Starter #3
Damaged bell housing would seam to be the most reasonable explanation.
Looking closely at the SIMI bell housing this morning, it does look like it's had a rough life. Lots of scuffs and abrasions but I don't see any cracks or obvious bends.

After I had unbolted it from the rest of the transmission, I did try fitting it to the 1600. It still wouldn't come together.

With the 1600 already installed in the car and the FGR Bellhousings on the transmission, I had no problem mating up the transmission to the engine.

If there isn't some odd application where Alfa moved the studs coming off the back of the engine, I'm going to presume this SIMI bell housing somehow got damaged.
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