th400 o.d.

[habitatxskate]

so last yr for my bday, my dad's best friend gave me a book called "how to restore your chevy pickup" never had a chance to read it, basically because its been under so much other crap..anyways i wanted to read about some stuff and learn more about transmissions and then they started talking about overdrive and then it jumped to the th35 and th400! i was like

but then they said you can convert it to a step up gear, a.k.a. overdrive. its in front of me now, talking about a 2wd, not sure if a 4wd is possible...

anyways for 2wd, disconnect the batt, then remove the driveshaft, then you bolt the thing on and reconnect everything..next you have your driveshaft shortened. pretty cool eh?

this is the kit made by "gear vendors"
http://www.gearvendors.com/custom.html

 

[Babaganoosh]

My Dad has there kit on his 89NBS th400 c3500, it's a awesome kit, we don't know a whole lot about it.(was installed my PO)

 

[habitatxskate]

while looking at the site you can run double overdrive! lol, don't know what that issssss...its a 2wd right? i wonder if they have a 4wd kit, or if it will work.

 

[AJMBLAZER]

It'll work with transfer cases. I forget if you put it between the trans and the t-case or on the very end after the t-case.


Know a guy running one of those on his CC with a turbo'd 6.2L diesel, TH400, 205, and 4.56's and he says for the money he spent and the utility of it he'd have just swapped in a built 700R4 if he had it all over again. Says he never found much use for the gear splitting ability and it ends up being a very expensive OD gear.

 

[4X4HIGH]

Gear vendor over/under drives cannot be used on a 4WD trans if you're in 4WD. The unit goes behind the tranny on 2WD and "i think" you can mount one behind the t-case on a 4WD but then only the rear axle would be affected by its use so you could not lock the front axle in or it'd be like running different gears front and back.

 

[roadnotca]

$3500.00

 

[cbbr]

Yep. I looked into that briefly as a way to get better mileage on long trips, but I would never drive enough to make up for the costs.

 

[dyeager535]

My dad installed one on his truck. OD is nice, but for the cost, go get a 4L80E or NV4500, period.

Gear splitting is worthless IMO, the ratio isn't .50, its like .75 or something, which means that it's not "half" the gear at all, which would actually be usable. 25% less gear in my experience is never enough, as you STILL end up bogged down, or jumping to the next gear...say 1:1 to 2:1 3-2 gear split, your option with the GV is .75:1 (or whatever it's gear ratio is, that's close) to 1:1, to 1.75:1, to 2:1. Look up the RPM difference at .75 or .5 OD compared to a 1:1, .75 really isn't that much at "normal" freeway speeds. 700's OD ratio is .70 IIRC, for instance.

To be effective, IMO you would want a .5:1 final drive, then from there a 1:1, 1.5:1, 2:1, and so on. THAT is a useful gear spread. I know GM trannies for the most part don't fall into the 1:1/2:1 gear split, but splitting the ratios that exist would be beneficial.