NEED ADVICE -1976 K10 / TH350 TRANSMISSION REPLACEMENT

[jfkelley]

The shop that’s installing my transmission said the 1985 TH350 K Series was longer than my previous transmission..?

[JohnnyPopper]

So they had to move the NP 203 toward the rear of the truck, and that would have made the Front Drive Shaft shorter, yes?

Can someone weigh in on whether there is a difference in a 1976 K type TH350 and one from 1985 please?

[Irish_Alley]

theres no difference, the only difference in the lengths is when youre dealing with a 2d trans.

[JohnnyPopper]

That's what I though Irish!

Is JFKelly being scammed by some imposter?

The world is so full of them today... 

[jfkelley]

I’m starting to wonder if this shop knows what they are talking about ..I had the rear driveshaft shorten ..So if it’s wrong looks like I will Be buying a new driveshaft @ $300 + more

[JohnnyPopper]

did they move your transfer case back?

[jfkelley]

I haven’t heard from the shop in a couple days ..I will follow up with them on Saturday

[Irish_Alley]

did they shorten the shaft or you?

im terribly sorry about throwing in the 700r4 into the mix and im guessing between you mentioning they have to lengthen the shaft which is wrong as the th350 only uses one case between all 4x4 and 4x2 applications and only changes the tailshaft for the 2wd. they should of never needed to touch the shaft if you google th350 length you will see theres only one
http://forum.73-87chevytrucks.com/smforum/index.php?topic=32506.0
theres the list ive compiled and you will also see theres only one adapter plate the th350-np203 uses.

[jfkelley]

So the shop called me and says the sleeve between the transmission and Transfer case is too long?...it wont fit..Why is the 1985 K series Transmission not fitting to my 1976 K series NP203 Transfer Case

[Irish_Alley]

alright so apparently the th350 uses two different outputshafts one for the 203 and 205 and another for the 208. the th350 and 208 were only out for a few years together so its a little more harder to find. im not doing so hot with information for you. you cant cut the longer shaft down due to the splines not covering the whole outputshaft. you might be able to find a spacer but then youll be looking at new driveshafts. i hate to say it but you might want to try and sell that long outputshaft th350 and get your rebuilt or try to find a good donor from the same wheel base as yours that has a 700r4/transfercase and driveshafts.

[jfkelley]

Ok so that I understand you correctly the 85 K series will not work with my existing set up ...So I will need to take the Old TH350 that came out and have it rebuilt...? Correct

[Irish_Alley]

yes the K one will not work with your t-case and driveshafts. you could get the np208/adapter that came off it and front driveshaft and just have the rear driveshaft shortened. or just get your old one rebuilt, which in the long run might be better because you dont know how much life is left the the "K" trans

[jfkelley]

Thanks Irish ☘️ For all your help ..The K Transmission was just rebuilt ..I may put it up for sale and have the old one rebuilt ..What if I get the Quick Adapter GM 700R 4WD to replace the GM TH350 adapter ? Will that work

https://www.advanceadapters.com/products/50-8505-adapter-to-replace-gm-th350-with-gm-700r4/

[Irish_Alley]

that adapter is to make the 700r4 work with your adapter/transfercase

[jfkelley]

Any idea to find an adapter to make that transmission work with my Transfer case ? The mechanic says he puts on the Transfer case adapter from the previous transmission the shafts not long enough ..What if I take that Adapter and have it Milled Down to where I need it to make it work ?