I am purchasing an '83 GMC 3/4 Ton w/ a 350 V8 from my dad in a few weeks. He recently lost the transmission out of it. But I havn't worked on the truck in a while and I don't remember what T-case it has. I am looking at swapping a 93-95 NV4500 into it to replace the stock 700R4 that was in it. Currently my biggest concern with the swap is the compatibility of everything. I was looking at swap kits on nv4500.com and tollico4x4.com (basically the same site I think) but they didn't offer a 700R4 to NV4500 kit. Oh and the truck is about 220 miles away, so I can't really run and just check the tag on the T-case.

Questions:
1. What T-Case is most likely in the truck?

2. Will the T-case bolt right up to the NV 4500 transmission with no bolt
pattern or spline issues?

3. I am a good mechanic/fabricator, but I don't know my Chevy's real well. Is
it standard for the crankshaft to be a 10-Spline in a stock 350?

I think this covers most of the stuff I havn't been able to find just using google. I appreciate the help and knowledge. :beer:

3/4 ton should have a turbo 400 in it with either a 208 or a 205 depending on the GVW of the truck. If the truck truly has a 700---then it would be a 208

The truck does have a 700R4 so thanks for the knowledge. Any idea on the compatibility of the 208 with the NV4500???

depends on the spline count of the nv4500 you would need one with 27 splines and it should bolt up if the truck that had the nv4500 had a np241 but if it did why didn't you get it to because its better

Well I am looking at just purchasing one from a online retailer instead of finding one at a salvage yard. Therefore I am kinda stuck with the NP208 for now.

Can anyone answer question 3 for me? Thanks. :beer:

3. I am a good mechanic/fabricator, but I don't know my Chevy's real well. Is
it standard for the crankshaft to be a 10-Spline in a stock 350?

you can put the round pattern chevy 205 on the back of the nv4500 with the stock adapter and a spacer. I just finished one for a buddy with a 72 model 3/4 and a 6.5 turbo diesel. I have another buddy that used a advanced adpaters kit that uses the figure 8 205. It replace the factory adapter with one with a different pattern. The clutch parts you can use the factory hydro pedals and master with a 88 model slave on the 4500 bellhousing. I used those parts when I put a 4500 in my dually that we tow with. Hope this helps.

Yes it does help as I wasn't quite sure what I was going to do for the hydralic clutch system. I figured a stock set up out of a 93-94 GMC.

Here is my new question: Is there any casting differences between the 205 and the 208?? Because my truck apparently has a 208.

The 208 behind your 700r will not have the same spline as your 4500 tranny,
you can use a 208 from a 4spd or a 400, it will bolt directly to your 4500 tranny without any conversion kit or adapter.
I have an 87 crewcab that I used the hydraulic pedals out of an 85 , 4500 out of a 97 , and the 208 from a 85 with the 32 spline count.

Ok thanks for letting me know, I thought I saw where I could order it with either a 27 or a 32 spline output shaft. I will look into it some more. Thanks again for the heads up! :beer:

So does anyone know what the bolt pattern/spacing is for the transmission mounting surface of an '83 700R4???

Also are most 350 crankshafts a 10-Spline?

the face of the tranny will have the common chevy bolt pattern. The bellhousing will have to be spec to the nv4500 unless you want to use one from advance adapters. The crank will take a flywheel it will also take the pilot bearing or bushing. I like the bushing less to mess up if it goes bad. I'm running a 12 inch clutch from where I work for a 85 model with the hydro factory parts. I had to redrill some crossmember holes.

The 10 splines are going to be on the clutch plate not the actual motor. You going to need to get a flywheel, and pilot bearing. They recommend a bearing for the NV4500 and not a bushing.

Ok, I understand now. Thanks for baring with me on that.

I assmume that a 32 spline output shaft would be better than a 27, please correct me if I am wrong. I plan on installing an atlas T-case at some point and ditching the 208, but the 208 has a 27 spline input. Would I be better off to order the nv4500 with a 32 spline output and look for a new input for the 208?

EDIT--> Just to clarify, I have been doing a lot of reading and posting on this topic when I have been quite tired. The whole drivetrain question about the splining of the crankshaft was quite ridiculous as I just realized. I know much more than what I have shown here, I just wasn't slowing down to think everything through. I appreciate the patience shown in this thread. I have been worrying to much about compatibility and I hadn't spent enough time thinking about the actual mechanical operations of this drivetrain. Again thanks for the help thus far, and I appreciate the knowledge that is being shared with me.

So any opinions on a 27 or a 32 spline output shaft for the NV4500?

I did the very swap that you are talking about. I used an NP205 instead of the 208. I think that if you are going to spend that much on an NV4500 spend another $100 on a good used 208. They are noot that desirable for the building community so you should be able to get one nearly free. My opinion don't even consider the 27 spline ang go straight to the 32 spline. You have so many options from there and they are stronger.

Alright, I will go with the 32 spline then. Thanks.

So what are some year/models that have a 32-spline 205??? Andy what would be a fair working condition price for the 205 T-case? I understand price is somewhat regional, but just give me a ball park figure. Thanks.

Bump*

So what are some year/models that have a 32-spline 205??? Andy what would be a fair working condition price for the 205 T-case? I understand price is somewhat regional, but just give me a ball park figure. Thanks.

should be any 85 and up ton maybe some 3/4 ton. I have seen them go for 50 75 dollars to a high of 400 dollars in my neck of the woods here is southwest va. Might watch ebay or pick up a aftermarket case and put your guts in it.

Alright I will start doing a little parts hunting. thanks.

NP241 fits also. 89-91 K5 & Burb are passenger-side drop. 4-spd and 4L80E are already 32-spline.

Round pattern 205 is 85-87 on all 1-tons, and through to '91 on same-body-style 1-tons and crewcabs.