Dead 700R4 - Now what?

[Zaar]

HR whats your thought on the underover drives?

 

[TexasOutlaw87Cummins]

Man i destroyed like 5 of these trannys

 

[HotRodPC]

HR whats your thought on the underover drives?

I like them alot, BUT they are not practical at all due to expense. If you can snag one out of an old RV for cheap, go for it. Do keep in mind, cost of conversion on driveshafts, crossmembers and mounting even if you found a cheap one. Just not cost effective. A conversion to a 4L80-E can be done much cheaper than buying a Gear Vendor unit and adapting it.

4L80-E is a good option, but also a bit pricey. Not Pricey compared to a Gear Vendor though.

 

[HotRodPC]

Man i destroyed like 5 of these trannys

Behind a 5.9 Cummins?? Uhhhh yeah. Probably like metal grinder. Made them look like hamburger meat inside I bet. Even Turbo 400's need to be set up right behind a Cummins 5.9. Allison is really the preferred Auto behind a Cummins. Then there is the Aisain which is an Inbred of the Allison. That's why if I do Cummins, I've already decided it's going to be NV4500 or might look into the NV6500. I have not dealt much with the NV6500 to know if it's holding up well.

 

[wildcatjason]

This wasn't behind a 6bt, was it? I tried it behind a 4bt for awhile and hated the way it shifted. Those things reach max torque at 1700 and redline at 2500 with a stock governor spring. The rpm range sucks for that engine.

 

[HotRodPC]

This wasn't behind a 6bt, was it? I tried it behind a 4bt for awhile and hated the way it shifted. Those things reach max torque at 1700 and redline at 2500 with a stock governor spring. The rpm range sucks for that engine.

The other issue you'd run into, is at that low of rpm, you woudn't be that hard on the throttle, so the TV cable that regulates throttle and pump pressure, you wouldn't be getting a good compression from your clutch pistons for that much torque and could sure burn up a 700r4 in short order, and also probably why it shifted like ****. Probably a very soggy spongy type shift.

 

[wildcatjason]

The other issue you'd run into, is at that low of rpm, you woudn't be that hard on the throttle, so the TV cable that regulates throttle and pump pressure, you wouldn't be getting a good compression from your clutch pistons for that much torque and could sure burn up a 700r4 in short order, and also probably why it shifted like ****. Probably a very soggy spongy type shift.

It was hard to dial the tv cable in. One notch felt way to late. The other world feel way to early. The 4bt has been known to torch em. I wouldn't try it behind big brother.