I have an 82 k5 blazer I have a new th400 (replacing a 350)& I'm trying to connect it to the transfer case (np208) but it seems I need some sort of an adapter because to t-case has 4 bolts and the trans has 6 bolts???? Anyone ever run into this?
CK5
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Transmission to transfer case????
- Thread starter K5Country
- Start date
The adaptors are out there. but they are a biatch to find, and from what I have seen, normally cost $100-$150.
Just an fyi a 241 and a 208 take the same adaptor, so that should help broaden your search
Just an fyi a 241 and a 208 take the same adaptor, so that should help broaden your search
All of GM's tans / t-case combo's use an adapter to bolt the pair together. These adapters are specific to the combo but like Deuling said there are a couple that will interchange.
Fyi, if the 208 came off of the th350 it will have the wrong spline count input shaft for the th400.
Fyi, if the 208 came off of the th350 it will have the wrong spline count input shaft for the th400.
Bad news, it's more than an adapter that you need.
First and foremost, how far does the output shaft stick out from the back of the transmission? There are 3 different GM 4WD output shaft lengths, only one of which really works with a 208.
If you're lucky enough to have the output shaft you'd need for an NP208 (it would stick out ~2.5"), you'll need an '84 and older TH400/NP208 adapter (commonly referred to as the "tall foot" adapter) and you'll need to change the input gear in the 208 to 32 spline to match the TH400 (the TH350 was 27 spline).
If your output shaft sticks out ~1-3/8" or ~4-1/2", I think you're out of luck. Well, you'd need a different output in the trans, which requires a complete tear down, which I assume you want to avoid.
First and foremost, how far does the output shaft stick out from the back of the transmission? There are 3 different GM 4WD output shaft lengths, only one of which really works with a 208.
If you're lucky enough to have the output shaft you'd need for an NP208 (it would stick out ~2.5"), you'll need an '84 and older TH400/NP208 adapter (commonly referred to as the "tall foot" adapter) and you'll need to change the input gear in the 208 to 32 spline to match the TH400 (the TH350 was 27 spline).
If your output shaft sticks out ~1-3/8" or ~4-1/2", I think you're out of luck. Well, you'd need a different output in the trans, which requires a complete tear down, which I assume you want to avoid.
If you find a tcase that was behind a 700r4 though (much more common IMO), it should work with the 400.
mwood1985
1/2 ton status
might be worth going to a 400/205 combo in this case. theres not much to find and its a little more common.
Well my buddy has a 91 gmc that came with a 700r4 241 combo, we put a th400 in it, and found the adapter, and bolted his original 241 right up no prob
Must be the newer 700s have 32 spline then.
Well my buddy has a 91 gmc that came with a 700r4 241 combo, we put a th400 in it, and found the adapter, and bolted his original 241 right up no prob
Must be the newer 700s have 32 spline then.
Nope, your buddy did some other magic you must have missed
There are aftermarket companies that make TH400 outputs with 27 splines and also 700R4 outputs with 32 splines (both are backwards from stock). Could've been that business.
ALL stock 4WD GM 700R4's were 27 spline.
ALL stock 4WD GM TH400's were 32 spline.
Nope, your buddy did some other magic you must have missed
There are aftermarket companies that make TH400 outputs with 27 splines and also 700R4 outputs with 32 splines (both are backwards from stock). Could've been that business.
ALL stock 4WD GM 700R4's were 27 spline.
ALL stock 4WD GM TH400's were 32 spline.
Huh thats messed up then... it was a stock ass truck when he bought it, but I guess somebody could have done something goofy with it, but i dought it as it still had the stock 700 241 combo
But we literally put a th400 in it and added the electric kick down to the gas pedal linkage, and his 241 bolted right up and he ran it for like 3 years until he blew up the th400.... Had the local guy build up a super beef 700 and we bolted that up and put the same tcase up to it...
Now Im confused and must look into it. Ill count the spline count on the 400 tomorrow when i get up there if I remember.
shaft id
I think the SM465 T-cases from around 82 and up also have 32 spline inputs,so a TH400 can be bolted up to them using the correct adapter..as long as the tranny output shaft is the right length also...
SM465/NP208 combos were used from 81-88 and all were 32 spline, as were the 89-91 SM465/NP241 combos.
All 84 and older SM465/NP205's are 10 spline. The 85-91 SM465/205's were 32 spline and all used the round pattern GM NP205, they came in 1 tons only.
if the splines don't match it's simple enough to swap the transfer case input shaft...most likely cheaper too...
