Welp, I think I may have screwed up by buying a MV7. I had assumed the MV7 and MV5 transmissions were basically interchangeable – why would there be significant differences in the “same” transmission between two cars made by the same company? This assumption turns out to have been a bad one.
It took about 4 weeks to get in touch with V8R – not the best customer service experience I’ve had. They finally told me that the MV7 requires a different frame rails, crossmember, and driveshaft. The MV5 driveshaft they provide uses an aluminum adapter to attach to the transmission (image below from @rdb138 ) and the MV7 driveshaft bolts directly to the transmission:
I wanted to understand what exactly drove the difference so I dove into the service manuals and parts catalogs (MV5, MV7) to try and understand the differences. I may have definitely spent entirely too much time doing this. From what I can make out, it seems like there are a few non-interchangeable parts but the important ones (input, output shafts, most of the shift stuff) are the same or at least interchangeable. The countershaft is different, but that’s to be expected since the gears are fixed to the shaft and the ratios are different. The primary differences are (bottom to top) the RR transmission case, transmission extension, and the output flange:
Basically the third and fourth transmission cases from the bottom and the output flange. Obviously the output flange is an issue since it interfaces with the driveshaft, and the transmission extension (top case) is an issue because the transmission mounts are different:
That leaves the RR transmission case. I’m inclined to say these are not interchangeable – the 1-2 shift shaft isn’t interchangeable, which could mean it’s a different length. If I say, had a MV7 and wanted to swap over the MV5 case, I’d be worried that the bushing the 1-2 shift shaft rides in would be in the wrong spot and the shaft would either bottom our or be unsupported. Hard to tell without having both in my hands, they look pretty similar in pictures but they have different part numbers for a reason.
So, what does this all mean? I THINK if I can get my hands on the MV5 output flange and transmission extension I may be able to make this work with the MV5 kit I’ve got. I’ll have to figure out the reverse sensor wiring and go without a transmission temperature sensor, but those are acceptable compromises.
The hard part is going to be finding the parts – you can buy the transmission extension new (~$150) you can’t buy the output flange from Chevy. A used MV5 is ~$1k, unfortunately. Anyone have a MV5 they want to part out for the sake of science?
The other option would be to just buy a MV5 and use it as-is. But where’s the fun in that when I could make this way more complicated?
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