I was just woundering which trans and what gears ya'll think I should put in my old girl. Right now I have a 91 with a 4.9L with a 5 speed with 3.08s on 33" tires, I just parted out an 89 with a 4.9 and a 4 speed and 3.08s (keeped the motor,trans, t-case, and axles the frame was rotted though and the cab was gone.) What I want to know is do ya'll think I should put the 4 speed in with 3.73s or keep the 5 speed with 3.73s or 4.10s. I use the truck for mainly playin in the mud, trail ridin, and tractor pulls but also use it for haulin wood and a backup daily driver so streetably is still a must.

 

I actually did that I had an 85 with the 4.9 4spd t18 and I bought my 91 4.9 with the 5 spd it was 2wd tho and i didn't feel like hunting down a output shaft housing So I put the 4spd in so I could have 4 wheel ( did the axle swap too). If I had the option I would do the 5 spd. It was a lot smother and I'm running 35s so it struggles to get going up hills sometimes. (also 3.73 gears). If you do 4.56 you should be fine with the 4 speed but like I said I'd
Like to have the 5 speed.

 

Sorry 4.10s would work too. And if you gonna be playing in the mud and doing tractor pulls the 5 Speed is probably Your Best bet.

 

What kind of rpms were you running goning down the highway with the 4 speed?

 

what?????

if your running mud you want a higher gear ratio for tire spin, you also want a high reving motor, which the 4.9l is not.

and for tractor pulling you want low gears, for torque, and lower rpm range this the 4.9l is famous for.

it doesnt matter what trans you have in it, 5 speed or 4 speed it all depends on the gear ratio inside the trans. for mudding and pulling or just about any offroading, hauling wood, you wont go past 2nd gear anyways,