TH400 Needs Overdrive... 4L80E swap? Bolt on OD?

[stutaeng]

Here's a little article I just came across about the Gear Vendors: https://www.motortrend.com/how-to/gear-vendors-overdrive-mileage-drivability-performance-review/

1.2 MPG increase...
But performance increase seems pretty impressive to me!

 

[sewlow]

theres a big ass motorhome parked here, a 78 dodge.... low miles if anyone is interested.... 440.... I want it gone.... It's not mine. I should absolutely take a look under it and see if it has a GV unit. I never thought of that.

Hey Sewlow, we share the same name...

Cheers!

Al

Well...I've been 'The Boss' & I've been through a divorce, so I'll answer to just about anything. Lol!

 

[PlayingWithTBI]

theres a big ass motorhome parked here, a 78 dodge.... low miles if anyone is interested.... 440.... I want it gone.... It's not mine

Just call Freiburger on Hot Rod Garage, he'll come out and cut it up with a chainsaw and take the engine free of charge. The last time they had to pay for the motor home

 

[SasquatchOnDeck]

Here's a little article I just came across about the Gear Vendors: https://www.motortrend.com/how-to/gear-vendors-overdrive-mileage-drivability-performance-review/

1.2 MPG increase...
But performance increase seems pretty impressive to me!

Exactly what i was afraid of. if i spent two grand getting a 1mpg boost and no more gears, id be sick until i totaled the truck.

 

[plskthompson]

I was looking into a GV for mine, since it’s already a 2wd, and couldn’t find one for less that $3k. A little more cash would give me the 4L80 with the controller, so the GV is out of the question, IMHO. For the cost difference in what I was finding, I’ll do the 4L80e swap just to have the lower RPM. Like I told someone the other day, I didn’t get this truck for fuel mileage, I got it to work, but an extra gear on the Hwy wouldn’t hurt.

 

[6Wheeler]

Looking for some experience and advice. Bought a 89 ECLB last year, It's got a 454/TH400, 4x4, a SRW Dana (60/70?) with 4.10 gears, a questionable dually conversion, and finally, as all TH400s, no overdrive. Coming from a 88 with a 350/700R4, and seeing as i don't own stock in Exxon-Mobil, it's damn miserable.
LSS, i'd love to daily this truck, but that's going to involve putting in overdrive, the cheaper the better. I'm leaning away from the gear vendors at the 2,000$ price point because i'd still only have 3 gears, but if there's a cheaper alternative, i could happily avoid freeways and stick to 60MPH two-lanes.
I'm pondering a 4L80 swap, could it be done without the E on the end? I'm going to delete TBI to remove electronics, i'm trying to not add more, but i don't know that there's any other option there. Would a 4L80E pop right in where the TH400 was? I don't now what transfer case is in there, or if it even matters, and to complicate things, I'm on deployment and can't exactly look at/under the truck for a couple months.
Has anybody done anything similar? What other bolt-on O/Ds are out there? TIA

Sorry can't help you, but that's a nice looking Truck, Good Luck....

 

[GMTMark]

Definitely keep the fuel injection unless you want worse mileage. 4L80E and a controller is the way to go. If you know a reliable transmission guy then turn it over to him. My opinion.

 

[PedroC]

Looking for some experience and advice. Bought a 89 ECLB last year, It's got a 454/TH400, 4x4, a SRW Dana (60/70?) with 4.10 gears, a questionable dually conversion, and finally, as all TH400s, no overdrive. Coming from a 88 with a 350/700R4, and seeing as i don't own stock in Exxon-Mobil, it's damn miserable.
LSS, i'd love to daily this truck, but that's going to involve putting in overdrive, the cheaper the better. I'm leaning away from the gear vendors at the 2,000$ price point because i'd still only have 3 gears, but if there's a cheaper alternative, i could happily avoid freeways and stick to 60MPH two-lanes.
I'm pondering a 4L80 swap, could it be done without the E on the end? I'm going to delete TBI to remove electronics, i'm trying to not add more, but i don't know that there's any other option there. Would a 4L80E pop right in where the TH400 was? I don't now what transfer case is in there, or if it even matters, and to complicate things, I'm on deployment and can't exactly look at/under the truck for a couple months.
Has anybody done anything similar? What other bolt-on O/Ds are out there? TIA

My 1995 GMC K3500 TBI 454, 4L80e with 4:10’s gets maybe 13-14 mpg at 55 mph it get around 10ish mpg at 70 mph. Your not going to get good mileage on a 7,600 lb truck.