tranny/transfer case swap issues

[Leadfoot]

I finally got my TH400 and round pattern NP205 with adapter in the truck.

The issue I am having is I tried installing the transfer case shifter and there is no way it will work. The top half of the shifter is pushed all they way forward to fit up through the hole and it's a much steeper angle than it should be. I can't even pull it back to shift as it's hitting the edge of the hole in the floor.

I was told that all NP205 shifters were the same, but after looking at a friend's 1985 1 ton dually (round pattern 205 mated to a TH400), the shifter has several bends in it to compensate for the location.

It also seems to me that the hole in the floor is in a different spot. His is a one piece floor board, while I have the removable tranny hump. It could be an optical illusion, but the hole in my floor looks furthur forward. Does anyone know for sure if it is and/or what applications used the different NP205 shifter (maybe just 1985+ one tons??)?

Does this make sense??

 

[Backroads]

Whay tranny and t-case were in the truck before the swap? What kind of truck is it? - blazer, 1/2 ton, 1 ton

 

[Leadfoot]

Whay tranny and t-case were in the truck before the swap? What kind of truck is it? - blazer, 1/2 ton, 1 ton

My bad.

It's an 80 K20. Originally with a 350/TH350/Figure 8 NP205. I had swapped in a 700r4/Figure 8 NP205 and had the original shifter modified to account for the longer length of the tranny and it worked fine, now it has a 454/TH400/Round 6 NP205 and neither a stock shifter or the modified shifter will work.

One question, does anyone know if the shifter for a 205 behind an automatic changed in 1985?

 

[dyeager535]

Somewhere on here I posted about this, picture with both shifters side by side.

The problem was the adapter length changing. It obviously put the t-case back further, to get the shifter to fit the same hole in the floor, GM had to modify all the angles.

A couple of examples: pre-1985, 205 behind a 465 had a 7" adapter. '85-later, the adapter is 10" long. The shifter from a 4L80E/205 combo (1991 V3500 donor) works for the '85-later 465/205 setup.

As far as I can tell, in 1985 GM decided to use the adapter as a way to keep the drivelines the same length regardless of transmission, instead of having different drivelines based on drivetrain. Obviously some variations based on wheelbase/t-case, but a K5 with a 465 or 700R4 in 1985 should have the same driveshaft lengths front and rear, while prior to that, a TH350, 400, 700 and 465 probably all had different length driveshafts.

All 205's prior to '85 used the "hourglass" t-case adapter pattern, correct? I've never dealt with the TH400/205 setup.

What it sounds like you've got is a 1985+ adapter. If I remember other posts correctly, the TH400/205 adapter can be made to fit the 4L80E without shortening the length, so that would seem to indicate any post-'85 shifter should work.

I tried my setup with the original 205 (70's) shifter, and there was no way it would work.

 

[Leadfoot]

Somewhere on here I posted about this, picture with both shifters side by side.

The problem was the adapter length changing. It obviously put the t-case back further, to get the shifter to fit the same hole in the floor, GM had to modify all the angles.

A couple of examples: pre-1985, 205 behind a 465 had a 7" adapter. '85-later, the adapter is 10" long. The shifter from a 4L80E/205 combo (1991 V3500 donor) works for the '85-later 465/205 setup.

As far as I can tell, in 1985 GM decided to use the adapter as a way to keep the drivelines the same length regardless of transmission, instead of having different drivelines based on drivetrain. Obviously some variations based on wheelbase/t-case, but a K5 with a 465 or 700R4 in 1985 should have the same driveshaft lengths front and rear, while prior to that, a TH350, 400, 700 and 465 probably all had different length driveshafts.

All 205's prior to '85 used the "hourglass" t-case adapter pattern, correct? I've never dealt with the TH400/205 setup.

What it sounds like you've got is a 1985+ adapter. If I remember other posts correctly, the TH400/205 adapter can be made to fit the 4L80E without shortening the length, so that would seem to indicate any post-'85 shifter should work.

I tried my setup with the original 205 (70's) shifter, and there was no way it would work.

Thanks for the reply.
I'm assuming you are referring to the photo you posted in a previous response to me:

The shifter in my buddy's 85 one ton (400/205) looks even different. It looks more like the bottom shifter with more bends in the actual round stock, rather than offset near the pivot bolt.

I believe you are correct in that all pre 85 t-cases used an hourglass (figure 8) adapter and the later ones used a round one. I'm hoping somebody with an 85+ 1 ton with a th400/Np205 combo may have a pic or two of a shifter for me to verify.

Also, it would be cool to know if the placement of the hole for the transfer case shifter moved slightly as well in 85...

 

[dyeager535]

I don't think the hole moved in the 80's...the 208/241 use the same shifter all the way through, and my later 205 shifter fits.

The early shifter, unmodified, (with the older/shorter adapter) didn't sit in the 208 cutout very well, it was close to the sheetmetal.

It could have been, again to simplify stuff, but if the 700 and 465 combo's with 208/241's used the same hole, no reason they couldn't with the 205.

My parts manual should list the shifter, I'll try and remember to look that up in a couple of days. The manual is '85-88, so the correct vintage for the 400/205 combo you are talking about.