I have heard of people switching the V8 and the 4cyl tranny between the two but most of the talk centered around how the shift cables mount and are used. I do not have 1st hand knowledge if the mating surfaces
For the Citroen, Page 8 of Section FD of the Service manual says; "If a clutch bellhousing is to be replaced separately from the transmission, the transmission must be returned to the factory in order that the new bellhousing may be fitted and the output shaft housing mating faces machined. The gearbox serial number (stamped on top front) is then repeated on the top rear face of the bellhousing."
Don't know if the same is for the Renault. I don't recall them saying anything special for the Renault in that section. With the specificity given for the Citreon and nothing said for the Renault then I would suspect the matching is not necessary. Alignment will be very important though.
Yeah, I was aware of the requirement for the Citroen trans - that's why I am curious about the UN1 situation. Nothing at all about it in the service manual. Anyone out there ever done a bell housing swap on a 1989 or later Esprit? Any issues?
The bell housing supposed to be the same, the only difference I found was the bearing used inside the tranny. I only found this out when I did my upgrade on my transmission with parts that GTO sent me. Everything was perfect except that the inside bearing was different and they told me that around 95' there was a change, but other than that it is the same. So if you are just changing the whole thing and not just the internals you should be fine.