Hi from IL

[lscaspall]

Hi all, I am restoring my deceased father's 1974 Chevy K20 Cheyenne that he purchased brand new that year. My father was a farmer and the truck went through many modifications over the years, including a swap from the original TH400 transmission to a 700R4. Not sure why didn't just replace the original tranny with another TH400. At any rate, I'm converting the truck back to original specs and discovered that the holes on the transmission crossmember do not line up with the mount holes on the NP203 adapter bracket (#376291). When setting the transmission in place, the adapter holes are about 1 inch rearward of the crossmember mounting holes. It is possible that the transmission crossmember was moved slightly forward when my father swapped the original TH400 for the 700R. I'm hoping someone may have some insight on this and be able to suggest a solution.

 

[Mr Clean]

 

[legopnuematic]

Welcome from Missouri.

 

[Shorty81]

Welcome from Ohio

 

[JamesSam]

Welcome from VA.

 

[animal]

 

[ali_c20]

Welcome from Austria. Got pics?

 

[brooksman9]

Welcome friend

 

[WFO]

Welcome from the Texas Panhandle.

 

[Strick]

Welcome from The Tarheel State. It may be possible that the TH400 had an NP205 behind it instead of the NP203. The crossmember mount is bolted to the NP203 and then to the transmission whereas it is the opposite for the NP205. There may be a length difference between the two mounting styles but I don't think so. It seems that in years...decades past...that I'd pull the NP203(my nemesis) and bolt the NP205 directly in place and use the rear driveshaft as they were different. Seems that those crossmembers from '76 and older were also riveted to the frame instead of bolted. I'd suggest looking through the forums for a transmission tech discussion and see if you can find some better info that I've supplied. Good luck and again, Welcome!

HS

 

[idahovette]

75 K20, bought new June 1975 350,350, 203, 4.10 rear, crossmember bolted never riveted.

 

[87scotty]

Hi all, I am restoring my deceased father's 1974 Chevy K20 Cheyenne that he purchased brand new that year. My father was a farmer and the truck went through many modifications over the years, including a swap from the original TH400 transmission to a 700R4. Not sure why didn't just replace the original tranny with another TH400. At any rate, I'm converting the truck back to original specs and discovered that the holes on the transmission crossmember do not line up with the mount holes on the NP203 adapter bracket (#376291). When setting the transmission in place, the adapter holes are about 1 inch rearward of the crossmember mounting holes. It is possible that the transmission crossmember was moved slightly forward when my father swapped the original TH400 for the 700R. I'm hoping someone may have some insight on this and be able to suggest a solution.

Welcome what parts of Illinois are you about I'm central.

 

[Strick]

1975 350,350, 203,

I was going to mention that I've seen 20's with TH350 trannies which are shorter than the TH400. @Idaho, you bought your K20 when I was only a few months old!!! Wow.

HS

 

[lscaspall]

Welcome what parts of Illinois are you about I'm central.

Hi @87scotty just east of Macomb.

 

[lscaspall]

Welcome from The Tarheel State. It may be possible that the TH400 had an NP205 behind it instead of the NP203. The crossmember mount is bolted to the NP203 and then to the transmission whereas it is the opposite for the NP205. There may be a length difference between the two mounting styles but I don't think so. It seems that in years...decades past...that I'd pull the NP203(my nemesis) and bolt the NP205 directly in place and use the rear driveshaft as they were different. Seems that those crossmembers from '76 and older were also riveted to the frame instead of bolted. I'd suggest looking through the forums for a transmission tech discussion and see if you can find some better info that I've supplied. Good luck and again, Welcome!

HS

Thank you for the insights. Truck came from factory with 400 and NP203. Cross members were bolted. Heres a pic if I can get it to attach. Transfer case not installed yet.