X1/9 5 Speed Transmission ID

The story, is that the X1/9 5 speed transmission up to 1987 is based upon the Fiat Ritmo/Strada mechanicals.

Post 1987, the X1/9 5 speed transmission is based upon Fiat Tipo mechanicals.

As far as I can determine, all the 5 speed mechanicals are interchangeable but the differential of the Tipo equipped transmission is more robust.

Question: If the above statement is correct, how can one identify the Tipo based transmission - are there any external casting or serial number identifying features?

Tipo is a 'top change' transmission... so unless there was also a major redesign of some internals...maybe some cross breeding of internal parts ? like the shift forks are totally different?... final drive set (cw&p in 4.077 doesn't appear in Tipo specs but I only have 1372/1580 specs for 1988) and AFAIK they are tripode style inner axle joints) or maybe some major redesign in gearlinkge...

maybe it's another 'urban myth'? maybe they mean a 'top change' Uno turbo type gearbox... I'm pretty sure that runs the late synchronisers and a CV joint style inner axle coupling style outputs, so would at least have some direct diff similarities... assembly diagrams and pics in the workshop manuals just doesn't show the diff housings etc in that much detail to know if they are different...but they look awfully similar...

I don't think the tipo's final drive set would make a complete 'factory' mix and match gearbox possible .... unless by some freak the PCD of the Tipo CW's threaded bolt holes was identical to the x19/strada/ritmo style CW (which for example an X19 four speed tripode diff CW isn't)

It does look like (from assembly photos in the workshop manual) some parts could interchange and you would get X19 1/2 style synchros on 3/4 and also 5 as well... maybe that's the holy grail to this myth??... it would be a nice upgrade.... another plus is that the top change gearbox also uses needle roller bearings instead of bushes on the secondary shaft for the 1st and 2nd gear.

SteveC

I've been trawling thru parts manuals today to find some interchanges between later transmissions (tipo /delta /uno) and looks like there are a few possibilities, with minor parts like bearings that have slight upgrades to construction ... so it looks like perhaps Fiat began to address the "chatter in idle" by redesigning some of the bearings, which dimensionally look like they might swap over, and if that's the case could have found their way into very late X1/9 transmissions.

Has anyone had a known 1988 vehicles transmission apart?

I put this here in this thread 'cos it seems sort of relevant.

I can't help but notice GeoffP made just this one post, jan 6, came back to look at it jan 9, and hasn't been logged in since...obviously he didn't like the answer he got... and offered no thanks. (Pretty rude really)

SteveC