sdmuleman

Finally got done with my trans rebuilt/46rh conversion to lockup and then when I went to bolt it up realized that it's not going to fit on the stock 1st gen adapter plate. Apparently I overlooked that in my research. So the question is what's the best way forward? I see 2 options - replace the 1st gen adapter I have with a 2nd gen or machine a spacer to fit between the 1st gen housing & trans.

I have a CNC Bridgeport mill & a large lathe, so I can machine parts as needed.

Replacing the adapter seems to be the common approach, but I understand that then you need a 2nd gen starter and there's interference issues, plus they seem quite pricey from a quick ebay search. Can the 2nd gen adapter be machined to fit the 1st gen starter or to clock the 2nd gen one off the frame? I'm not keen on a solution that requires me to bend the frame flange.

On the other hand, it seems like it wouldn't be hard to get a chunk of 1" aluminum plate and machine a spacer. I've got a 1/8" spacer already (thought I needed it for thicker flexplate) that could be used for a template, or try to find an actual drawing of the bolt pattern. Bolt positioning and parallelism should be the critical dimensions, which I can easily do with a template and the mill - inner and outer shaping could be done with plasma if I had too, though it would be much neater to machine it out. Any reason this wouldn't work? Anyone know the exact thickness difference? What I've found is about 1", but I'd obviously need more exact info. Anyone have a drawing?

Thoughts?

Thanks,
~John

Angry Johnny

1 1/8 inch is as close as I can tell. You could make a spacer but the critical point is going to be the dowels that keep the transmission and engine centered.

sdmuleman

Yep, would have to replace them with longer one. I'd expect they're standard diameter and it wouldn't be hard to find longer ones, but that is a concern. Maybe machine them if I had to. They would be longer, so more potential for misalignment, but if the spacer is a tight fit on the dowels I don't foresee any major issues.

kensmachine

Buying a plate that size isn't going to be cheap them the time to make it mite make the right bellhousing look cheaper . is a BP going to have enough travel to do the bolt holes in one setup. I have done this kind of thing made the part when I could have bought the part because I thought I could make it better or after buying a new POS part I made a good one .Ken

thrashingcows

I have a NV4500 with 2nd Gen parts and my frame only needed a 1/4 to 3/8 trimmed off the upper portion of the frame near the starter....barely noticeable and highly doubt it has affected the strength and integrity of the frame....so my vote is shop for a 2nf Gen adapter and starter, try car-parts.com they link 1000's of junkyards so maybe you can find the part cheaper through them?

sdmuleman

Plate would cost a bit, but what I found online was about $150-200 for a 2x2 1" plate, which is less than what I've found the adapter for. Haven't checked the local metal yard to see what it actually is though... could be an old price. On the flip side, I'd also be getting a fair bit of leftover aluminum plate stock that would be useful later.

Wouldn't be able to do all the holes, but I think I could mitigate that and do it in 2 setups. My BP is 12x18" travel, so what I was thinking was to setup a pilot hole/pin in the center and then do one half, rotate it 180* and do the other half. Shouldn't be hard, and I've got a template to double check. Time is certainly a concern though. On the flip side it's CNC, so there's some ability to do other stuff while monitoring it, and gives me an excuse to use and learn my toys more.

Also factoring into cost is that I have a perfectly good 1st gen starter already, so I'd need an adapter and a new starter.

Good to know it's that little frame mod - something I read made it sound like considerably more.

Can't find a listing for trans adapter on car-part - and ideas what to look under? There's one on craigslist I'm looking into but it's several hours away. .

oliver foster

Sounds like you haven't asked the right guy for an adapter plate then.
PM me if you decide you want to use an OEM 2nd gen adapter plate....I know a guy, who knows a guy with some spare Cummins parts.

edwinsmith

And who would THAT be Oliver?

sdmuleman

Sent you a PM Oliver.

Thanks.