Jet 4L80 6-speed conversion

[afgunn]

Anyone know where these are available anymore? Jet stopped making them 2 years ago. Truck Performance just had a sale and sold out.

I am not a tranny guy so, you tranny guys jump in and correct me where I am wrong.

The 6-speed conversion by Jet required their new valve body and the shifts had to be made manually. Probably had to shift manually because Jet did not have the expertise to change the PCM to shift automatically so, they modified a valve body to make manual shifts. I am also taking a swag and saying that the valve body would not be necessary if the PCM were reprogramed to do the shifting.

Unless I am wrong (high probability) the extra 2 gears are obtained by applying the OD on 1st and 2nd gear and no rerouting of fluid is required (hopefully). The "gears" of the Jet 6-speed conversion are as follows: 1st, 1st+OD, 2nd, 2nd+OD, 3rd and OD. If only a reprogramming of the PCM is required, I will bet that I can get a company to work with me (hopefully?).

Also, I have found a company that offers a new planet gear with a 2.75:1 1st gear and 2.57:1 2nd. This could make for some more interesting gear ratios. Of course, this would require a trans removal and disassembly/assembly. Would not want to do this until doing a rebuild.

OK, you tranny guys, jump in?!

[More Power]

About 5-6 years ago, Jet was advertising their 6-speed 4L80 conversion. I was all ready to go for it - to install in the 6.5 project truck (I had already bought their 4-speed version). They hemmed and hawed for more than a year, then finally said there were problems they couldn't overcome and would be dropping the upgrade.....

Never did hear what the problem was.

Jim

[afgunn]

They must have figured their problems out although, I was told by JET that it had to be shifted manually. So, maybe the automatic shifting is what they could not accomplish without too much cost or effort. I was told by JET that they stopped manufacturing this kit (valve body) about 2 years ago. Truck Performance just had some on "special" for $1200 (seems like too much) but, now they are sold out.

I am interested in this and will continue to check it out and see what I can discover and accomplish. I am an Electronics Technician by trade and have done some programming over the years - that is not to say that I can learn the PCM but, I am willing to give it a shot. I just need the right info.

A lower 1st and 2nd gear with 6 speeds on a 4L80 - seems like this would be interesting to quite a few people with our vehicles but, maybe not.

Thanks a lot for the info and interest Jim.

[DA BIG ONE]

The 700 r4 widebox can be built to withstand the 6.5td even when modified. So, a gear venders setup would multiply gears x2, and other gear splitters can be adapted too.

The 4L80e goes x2 w/gear venders too and keeps the automatic shifting.

http://www.transmissioncenter.net/4L80E.htm

[Robyn]

I personally would use the Gear vendors box. Its time and BUBBA tested and works well. Not cheap but is easily installed behind the 4L80 or the T case in 4X4 trucks.
Very good value for the $$$$$$$$$$$