thoughts on a new tranny?

[Lifted 74]

I've got a 74 3/4 ton with a 400sb, 9" of lift, 38" swampers, and the original 3spd auto. Looking to replace the tranny with another auto, any recomendations? I'm not sure what the gear ratio is but the 3spd is killing me on the hwy at 60-65mph.

[snibook7537]

Maybe a built 700R4, or a 4L80e.  both overdrive

[DustyRusty]

I'm not sure what the gear ratio is but the 3spd is killing me on the hwy at 60-65mph.

Do you mean the differential gear ratio or the final gear ratio of the trans?  What do you mean 'the 3spd is killing me at 60-65 mph'?  At 60-65 mph, are your revs too high or too low, or is the gas mileage poor?  There are easy ways to determine the differential gearing.

Give us some more information and we can give you a more complete answer.  Those 38s may be part of the problem; you may be way down low in the powerband of the engine at your stated speeds.  In that case an overdrive trans won't do anything for your situation. 

If an overdrive is really the end result, I agree that a 700R4, 4L80E is good.  Also consider a 4L60E which may be a little cheaper and more readily available than a 4L80E.

Rusty