4L80e

[Tevon]

Hey everyone currently have a 350/TH400 in my truck and im swapping a 5.3, and 4l80e into it.

For a stock driveshaft to be used what do i use?

Btw the transmission is from a 1995 3500 truck.

[toddoky]

Originally Posted by Tevon

Hey everyone currently have a 350/TH400 in my truck and im swapping a 5.3, and 4l80e into it.

For a stock driveshaft to be used what do i use?

Btw the transmission is from a 1995 3500 truck.

Does your TH400 have a short or long tail shaft?

[Tevon]

Originally Posted by toddoky

Does your TH400 have a short or long tail shaft?

Honestly have no idea this is what it looks like
Posted via Mobile Device

[toddoky]

Originally Posted by Tevon

Honestly have no idea this is what it looks like
Posted via Mobile Device

That is a typical long tail shaft truck version TH400, which is a few inches longer overall than a 4L80 case. You would have to have your driveshaft shortened if you wanted to leave the engine/trans mating plane in the stock location (otherwise know as 1" set-back). The only way you could use your stock driveshaft as-is, would be to mount your 5.3/4L80 combo forward by a few inches, which I wouldn't do personally.

[crazy longhorn]

I may have missed something in the mix....but my understanding , is that he is using the 4L80 trans. If that be the case, the shaft needs to be lengthened? If I ,missed the post, disreguard my reply. on your short bed truck (1 pc shaft), you can have a shaft built reasonably. Shove the yolk all in the trans, mark it with a sharpie, then pull it out 1", make another mark. At thi point (with the weight on the truck), on the wheels....measure from the center of the U joint spot on the trans yolk, to the center of the U joint on the rear diff. this should give you center to center on your U joints. Talk with the shop, doing the shaft, to be sure that your measure is on the same page, with them. Longhorn

[toddoky]

Originally Posted by crazy longhorn

I may have missed something in the mix....but my understanding , is that he is using the 4L80 trans. If that be the case, the shaft needs to be lengthened? If I ,missed the post, disreguard my reply. on your short bed truck (1 pc shaft), you can have a shaft built reasonably. Shove the yolk all in the trans, mark it with a sharpie, then pull it out 1", make another mark. At thi point (with the weight on the truck), on the wheels....measure from the center of the U joint spot on the trans yolk, to the center of the U joint on the rear diff. this should give you center to center on your U joints. Talk with the shop, doing the shaft, to be sure that your measure is on the same page, with them. Longhorn

Yes, the overall length of a 4L80 is shorter than a TH400 with the typical long truck extension housing, which means if you did an LS/4L80 swap into a squarebody originally equipped with a TH400 like the OP's and maintained the engine/transmission mounting plane in the stock location, you would have to lengthen the driveshaft. If the TH400 being taken out had a short 4" extension housing then you would have to shorten the driveshaft to work with the 4L80.

[crazy longhorn]

Originally Posted by toddoky

Yes, the overall length of a 4L80 is shorter than a TH400 with the typical long truck extension housing, which means if you did an LS/4L80 swap into a squarebody originally equipped with a TH400 like the OP's and maintained the engine/transmission mounting plane in the stock location, you would have to lengthen the driveshaft. If the TH400 being taken out had a short 4" extension housing then you would have to shorten the driveshaft to work with the 4L80.

Thanks for the reply....it sounds like we are on the same page longhorn

[hugger6933]

The yolk for the T400 should work out for the 4L80E