Options for a better tcase with th400

[Heyzeuscristos]

Hey all,

I just got a 78 k20 with a 350 mounted to a th400 and an np203 tcase behind it. Truth be told, i dont like the 203 because its a full time case and would like to swap it for a part time case like a 205 or something similar. However i dont really want to tear apart my tranny. Just asking to see if there are any part time cases that would bolt up with minimal retrofitting to the transmission? Id rather tear apart the tcase than my tranny at this point. Any options?

 

[1987 GMC Jimmy]

Hey all,

I just got a 78 k20 with a 350 mounted to a th400 and an np203 tcase behind it. Truth be told, i dont like the 203 because its a full time case and would like to swap it for a part time case like a 205 or something similar. However i dont really want to tear apart my tranny. Just asking to see if there are any part time cases that would bolt up with minimal retrofitting to the transmission? Id rather tear apart the tcase than my tranny at this point. Any options?

You could do an NP203 part time conversion kit. The Mile Marker 500 series of kits are the only ones I'm aware of, and I don't know if there are others, but that's something to consider.

 

[Heyzeuscristos]

I had a part time kit on my 77 k10, Its not the best solution but ill consider it if using a different tcase means ill have to change out the output shaft on the tranny

 

[1987 GMC Jimmy]

I understand that, and it's not the greatest route, but it's the least modification. Doing it by the book, you'd be looking at changing the case, shifter, and shafts accounting for a potential change in yoke style also. That's granted that the case you got had the TH400 adapter already. To me, the driveshaft lengths and yoke style differences would be the biggest pain with either having to hunt for correct used shafts or get new ones. If you do decide to go for it, there's a lot of internet support for an NP208 or NP205 swap including stuff on GMSB. The NP208 is a great case, but the 205 is legendary. I agree it would be much nicer, and if it were me, I'd probably have to bite the bullet and go for it just because I wouldn't be satisfied with the NP203.

 

[bucket]

Unfortunately, the output shaft is to short to run any t-case besides the 203.

 

[Heyzeuscristos]

Darn, thats what i figured but i wanted to make sure. I might just pick up a 205 and output shaft and hold onto it before i can rebuild the tranny. Just have to put a part time kit on my 203 in the meantime

 

[bucket]

It's really not a bad t-case if it's working and the shifter works how it should.