i'm buying an adapter for a 400 to a 205 and my question is what the difference between them the seller said this adapter was for a long slim 205 not round. what years are the long slims from vs the round ones. and is there a difference in the 400's thanks:D

the th400, th350, and 4 speed, all have different 205's i believe.

i know for a fact that an automatic 205 and a standard 205 are different, ask the seller if its for standard or automatic.

then you will know if its the one you need, there are alot more standards with 205's than autos

There are 6 different 205 adaptors.

The "tall" versions, fit '73 to '84, are as follows:

TH350
TH400
SM465
3 speed

The "short" versions, fit '85 to '91, 1 tons only, and are the "round bolt pattern", are as follows:

TH400
SM465

There are 4 different output shaft variations on the NP205's. They are as follows:

10 spline - fits SM465 and 3 speed
27 spline - fits TH350
32 spline - short input shaft, up to '84
32 spline - long input shaft, '85 to '91

So I'm going to have a bitch of a time trying to take the 205 out of my '86 crewcab automatic and put it behind my '84 K20 with SM465?

I recently bought a K30 for parts, just because it was 1 ton and 4x4. Oh well, even if I can't get the 205 to work easily, I'm sure I can make use of the D60.

So what's the idea behind a 'tall' or 'short' NP205?

Yes and no.

The 465 tranny's were a screwed up deal on the output shaft variations.

In '82 or '83, the 465 output shaft was changed to 32 spline. You could take the 208 behind it and mate it to any 400-version 208 tranny.

Around '82 was the last year for the 10 spline 465's.

But, the K30 1 tons retained the 10 spline 465's and used them ONLY with the 205's up to '84.

Then in '85, the 465's were changed to 32 splines, 205 AND 208 t-cases were able to share the same 465, but with different adaptors.

Making sense so far? Read on...

The "tall" and "short" adaptors refer to the height of the adaptors for which they sit on the crossmember.

If you have noticed the crossmembers from '84 and older are "flat", and the '85 and newer are "double-hump", you will understand the height of the "tall" adaptors are approximately 2.5" taller than the '85 and newer ones.

If I could, I would post pics of the crossmembers and adaptors that I have laying around, but I'm not a 'paying' member and therefore cannot post pics.

Now, in order for you to use the 205 behind the 465 in your K20, yes it will work, BUT, you will need to use the crossmember from the '86 K30 and that's all. The K20 stock crossmember will not work with the '86 adaptor.

Just go out and compare the crossmembers and adaptors. They will be different.