Np203 to np205 swap bolt in?

[Iceman21]

Ok I've searched all over and I can't seem to find this swap... Anyone have a write up??

So anyway I Blew my np203 up behind my th350 and 350... Swapping in a np205... I have the adaptor an coupler... Bolt in swap? Drivelines?

89 k5 7" suspension lift slip yoke drivelines front and rear.

I had a np208 but I later found out it came off a 700r4... Which I should have but the previous owner swapped in a th350. So anyway any help is greatly appreciated

 

[diesel4me]

I put a NP 205 in a 77 GMC K2500 that had a NP 203 in it when I bought it..TH350 tranny..

I had a '72 NP-205 and the TH350 adapter from another truck ,it bolted up to the tranny and crossmember no problem,the front driveshaft was now too long however,the rear fit fine with no mods,I did have to find a 3/4 ton yoke for the rear output though,the one on it was a K10 version that had smaller u-joints....your results may vary on the shafts,every truck is unique sometimes..I had to find a shorter front shaft ,I found one from a '69 K 10 that was a perfect fit,the only year they had one 23" or so long..
I could have chopped the original one down but it had a different yoke on it,the round ring with 4 bolts--I needed the old style one that had the typical yoke..
I had to do some mods to the tunnel where the shifter came thru it..

I think the 700R4 had the same bolt pattern on the tail as a TH350..so an NP-208 off one should bolt up ,but I cant say if the output shaft will have sufficient engagement or the shafts will work without mods or not..the shifter hole will have to be modified..the 4x4 TH350s are shorter overall compared to a 700R4 and have a stubby output shaft,so it may not be compatable..you can use a car or 2wd TH350 with a 6" tail shaft in place of a 700R4 with a spacer block and cutting the splined shaft about an inch shorter though..

 

[big dan]

All 4x4 th350s and 700r4s have 27 spline outputs but there are two different length output shafts on th350s. The long output as well as the 700r4 output fits np208s, this case is interchangeable between a 700r4 and th350 with no mods even the adapter is the same.

The short output on the th350 (you can also get a short output for the 700r4 but as far as I know its an aftermarket piece that wasn't offered from the factory) fits the np203s and np205s. These cases are interchangeable on the same tranny as long as you have the correct adapter. The np205 is quite a bit shorter than the 203 though so driveshafts will be different.

So to answer your question, yes np203s and 205s are interchangeable. And the np208 will work on 700r4 or th350 with the longer rear output.

 

[F-ingrob]

so im gonna jump in here and ask
if i can put a 205 on my 700r4
87 k5 and will it allow me to run long drive shafts

 

[big dan]

so im gonna jump in here and ask
if i can put a 205 on my 700r4
87 k5 and will it allow me to run long drive shafts

Youll have to have a np205 from a th350 and the adapter. Then you will have to buy the aftermarket rear output for a 700r4 and swap it in. I believe ORD is one of the companies that offers it. Yes you can do it but its not a bolt on because of the rear output of the tranny.

 

[xenomarine]

Youll have to have a np205 from a th350 and the adapter. Then you will have to buy the aftermarket rear output for a 700r4 and swap it in. I believe ORD is one of the companies that offers it. Yes you can do it but its not a bolt on because of the rear output of the tranny.

I did mine by using the spacer that ORD and other places sell, I did have to modify my output shaft a hair even though they told me the newer longer spacer wouldn't require that. I removed around 1/4" iirc.

 

[Iceman21]

Ok well it seems I have all the stuff i need to put it together thanks for the info. Hopefully my slip yoke have enough play in them. Should my crossmember from my 203 fit? It seems to have the same flat design but the holes look different, if so would it be a bad idea to drill new holes to fit my 205 adaptor plate?