Picking a New Transmission, 4x4

[benbloom]

So im considering swapping out my 4 speed with granny low because, well because its just too low! i do a lot of driving on the highway every day and spend less time puling stumps unfortunately, so, I'm wondering what would be the best replacement for daily driving. keep in mind its a 4x4, and i would like to keep it that way.

Thanks!

[kwmech]

How about a little more detailed info on the truck like tire size, gearing, tonnage

[benbloom]

Its a 1969 gmc 3/4 ton 4x4. i have 30 inch tires, what i believe to be 410 gears, rockwell T221 transfer case.

[MARKDTN]

Changing trans types in a 4x4 is an expensive proposition. Even assuming that the new trans will bolt to the transfer case, if the length changes then the transfer case shifter moves and both front and rear driveshafts are the wrong length. You might find a TH350 that is a similar length to the granny gear 4-speed, but not sure the input will be the same in the T-case. If you swap to an automatic you also need a different radiator, cooling lines, and a shifter or steering column (and linkage). Bottom line, you can probably buy a lot of fuel for what the swap will cost you.

[57taskforce]

Originally Posted by MARKDTN

Changing trans types in a 4x4 is an expensive proposition. Even assuming that the new trans will bolt to the transfer case, if the length changes then the transfer case shifter moves and both front and rear driveshafts are the wrong length. You might find a TH350 that is a similar length to the granny gear 4-speed, but not sure the input will be the same in the T-case. If you swap to an automatic you also need a different radiator, cooling lines, and a shifter or steering column (and linkage). Bottom line, you can probably buy a lot of fuel for what the swap will cost you.

The th350 is still the same 1:1 high gear as the 4speed. If your looking for overdrive than a 700r4 is probably your least complicated (electronically) route. Still have to deal with drive shafts and shifter as stated above. I'd refer the axles personally. Way way way less complicated.