SM465 into CUCV questions

[hobie237]

I've spent I don't know how many hours reading through the internet about this stuff, and every answer leads to more questions. Unfortunately, I can't do this the "easy way" of just dragging home a parts truck, since I have no place to put it.

I have a 1986 CUCV pickup. 6.2L diesel, TH400, NP208, D60/14-bolt FF. I was originally looking at swapping in a 700R4 but chose not to go that route, for a variety of reasons that I'd rather not rehash to complicate the issue. The important part, though, is that I have (among other things) an NP241 that was to be mated to the 700.

So, here come the questions:

1. What parts do I need? The SM465 can't be that hard of a swap, because it was a factory option. I know I need the trans, flywheel/clutch and clutch pedal, but what else?
a. Can I use the existing 208 that's bolted to the TH400?
b. Can I use either of the existing driveshafts?
c. If I can't use the 208, can I use the 241 that matches to the 700?
d. If I can't use the existing driveshafts, can they be modified to be used?

2. If I can't use those parts, what ones can I use? Are 3/4 and 1-ton parts the same? Or would I just want to go with 1-ton parts? How about gasser/diesel parts- are they the same or different?

I'm just more and more confused the more I read. Thanks for the patience.

 

[kennyw]

I've spent I don't know how many hours reading through the internet about this stuff, and every answer leads to more questions. Unfortunately, I can't do this the "easy way" of just dragging home a parts truck, since I have no place to put it.

I have a 1986 CUCV pickup. 6.2L diesel, TH400, NP208, D60/14-bolt FF. I was originally looking at swapping in a 700R4 but chose not to go that route, for a variety of reasons that I'd rather not rehash to complicate the issue. The important part, though, is that I have (among other things) an NP241 that was to be mated to the 700.

So, here come the questions:

1. What parts do I need? The SM465 can't be that hard of a swap, because it was a factory option. I know I need the trans, flywheel/clutch and clutch pedal, but what else?
a. Can I use the existing 208 that's bolted to the TH400?
b. Can I use either of the existing driveshafts?
c. If I can't use the 208, can I use the 241 that matches to the 700?
d. If I can't use the existing driveshafts, can they be modified to be used?

2. If I can't use those parts, what ones can I use? Are 3/4 and 1-ton parts the same? Or would I just want to go with 1-ton parts? How about gasser/diesel parts- are they the same or different?

I'm just more and more confused the more I read. Thanks for the patience.

You need to look for a SM465 with a 32 spline outputshaft and the correct adapter. They should not be hard to find. They were used from about '82-91. This will allow you to keep your current t-case and driveshafts (GM got smart in the 80's and left the driveshafts common).

The clutch I would buy a new kit from the auto parts store of your choice. They usually come with a plastic alignment tool now too.

For the bellhousing it will be easier to use the hydraulic clutch arrangement. From '84-87 (91) you can find everything you need in a stock truck. Pedal assembly, hydro bellhousing, and master/slave/clutch lines. All the holes are marked on your firewall where you need to drill to mount the master.

For these parts it will not matter if it comes out of a 1/2, 3/4 or 1 ton truck. It's all the same (for the clutch parts 2wd or 4x4 isn't even important).

The hardest thing to locate is the correct flywheel for the 6.2L diesel. They are out there but not easily found. I have seen some posts on here about them being available new, but requiring a core charge if you don't have an old one.

 

[hobie237]

I know I can get the flywheel new in a worst case scenario, but the core charge is actually more than some of the flywheels list for. There are several listed- do you know the tooth count?

That's awesome that I can keep the driveshafts. It would be silly for them to manufacture a whole array of different ones, when common parts would save a LOT on the production end.

I really appreciate the information!

Anybody know about relocating the crossmember? It would appear that all I have to do is move it and maybe re-drill it.

 

[kennyw]

I changed an '85 GMC K5 from a 700R4/NP208 to an SM465/NP205 (32 spline) and did not have to relocate the crossmember... like I said they finally quit changing the little stuff in the 80's. Since every transmission/tcase uses a different adapter anyway, they decided to make the driveshafts, crossmembers, etc all the same instead and change the adapter to make up the differences.

I have a flywheel at home on the shelf, but I've already posted the part # for it in another thread in the diesel forum if you do a search.

 

[AJMBLAZER]

On the driveshafts...did they use the same u-joints at the t-case on the different series? IE 1/2 ton vs 3/4 ton vs 1 ton?

My concern was that the stuff from a half ton might need different u-joints than a 1 ton t-case or axle.

 

[hobie237]

In my scenario, I'd keep the stock 208 case, and thus the driveshafts wouldn't even be touched, aside from their removal/reinstallation to swap the trans. It really makes sense that they'd keep everything the same where they could. WAY cheaper.

139 tooth flywheel and I'll have to re-shim the starter, correct? I search good.

 

[Russell]

139 tooth is correct, should have to re-shim your starter though, that was a problem specific to me, and wound up being the flywheel anyways.