25 MPG Dreamin' ?

[85 oil burner]

Well I must have put my question in the wrong forum so I will try this one,,I got a 3/4 ton 2WD 85' GMC BURB' with a 6.2 diesel,700 R4 trans. 3.73 gears and a 14 bolt "SF",I have a lot of plans to wake up the engine,beef up the suspension,and all that but I have another idea,I know that back in the day when gm made the 8.2 diesels in the medium duty they put a 7 speed trans. a.k.a. a 5 speed with a 2 speed rear,well being the crazy overkill guy that I am I would like to try to fit one of those in my BURB' I know the bell housing is going to be a "fun time trying to make that bolt up and driveshaft issues as well but that aint gonna stop me I know it would sure help that engine run a lot smoother at 70 and would def. improve mpg,so has anyone ever done this yet ? If so I wanna hear from ya,is this even possible or just a pipe dream yay or nay I would like to hear some feed back, thanx in advance. or ?

 

[Stroked]

Are you wanting just the 5-speed, or the 5-speed and the 2-speed rearend?

I'm assuming no one replied to your other thread just for the fact that most pickup guys have never wrenched on a heavy truck. We had a couple, but I've never messed with or even looked at the transmissions.

 

[Jims86]

Are you wanting just the 5-speed, or the 5-speed and the 2-speed rearend?

I'm assuming no one replied to your other thread just for the fact that most pickup guys have never wrenched on a heavy truck. We had a couple, but I've never messed with or even looked at the transmissions.

I replied.
I think its possible, but really not worth the co$t. some are reporting 22 mpg with a healthy 6.2
I say as long as the engine is mechanically sound, gearing should be the focus. A gear spread that allows the engine to work less, will yeild more of what you are looking for, like a 6 or more speed trans.
Aerodynamics are a big kicker with any truck from this era as well.