3 spd on the tree 72 k10

[6772iron]

I just bought 72 k 10 350 3 spd on the tree i want to put my 402 with an auto trans But I had a fella stop to buy a bed and he told me I would have to change cross members and everything he said i should just keep the 3 on tree that is much more rare and worth alot. is all this true and if so are the new cross members easy to pic up. thanks Brad

[RANDY COX]

Your engine cross-member will bolt right up to the 402 engine, as for the auto tranny it will have to be bolted to an auto adapter plate that bolts up to the transfer case...which may bolt up to the original tranny cross-member, I'm sure others will chime in and be able to give you more specifics but this is what I know...

[El Dorado Jim]

really rare to have a three on the tree 4x4, I have never seen one....may want to keep it original,just my opinion

[andrewmp6]

Most 3 on the tree i ever seen was 6 cylinders and i have seen them on 4x4s before.I would look for a 73-87 turbo 400/np205 from a big block.But if you want a over drive trans then you might have to use some kinda adapter or run a big block 4l08e/np205 which was 91 crew cab only its rare to find.You could use a later 4l80e but the t case 88-98 is driver side drop so you can't use it unless you swap a ford front axle,Or look in to a adapter kit to run whatever passenger side drop or go 2wd trans and a divorced t case.

[special-K]

The first thing I ever did in a 4wd that came witha 3spd is swap it out. It's a horrible transmission for a 4wd. 1st and reverse are so high they are worthless...and that puts more strain on the weak units. I busted one main shaft before getting to the swap on a '71 Blazer I had. I didn't change any crossmembers that I recall. And that one had the wimpy Dana 20 transfer case. I swapped a TH350/NP205 right in. It was easy, but I did have a complete '72 Blazer donor.

[Yukon Jack]

My 69 K20 had a 307 with the three on the tree from the factory with 4.56 gears. After fighting the tranny getting stuck when shifting occasionally I finally swapped it out for a 4 speed. Not sure if that was rare, but sure wasn't desirable for me at least.

[RANDY COX]

I thought they were pretty common atleast in my area, My Dad's ole 71 GMC 4x4 was a 350 with a 3OTT, the 72 Blazer 4x4 I had was a 307 with 3OTT, And the 70 Burb 4x4 was 250 six with 3 OTT...My ole Fleetline was a 3OTT, I guess I've driven more 3 OTT's than any other ones out there...I finally upgraded to a 4 spd in my truck now...

[6772iron]

thanks for the help everyone. I think on it threw the winter. Brad

[72 Super]

Got any pictures of your truck Brad?

Ray

[special-K]

Yeah, lets see that thang! You can get transmission/transfer case combos pretty reasonable. If you're still not sure after this winter, drive it and decide.

[blue 72 gmc 4x4]

I love my three on the tree! Still surviving with a 383 in front of it!