Has anybody swaped to the 4l80 from a 5 speed? I love the 6 speed,but I think I would be faster with an auto. The problem I see with the 4l80 is the PCM, I don't have the wireing harness. Do I have to re wire my truck with the automatic wiring harness? or just pay $670 for a tci 4l80 pcm controler? I really dont want to do any of the two options here. Should I just say the hell with it and put the th400 in and get a gear vender unit later?

 

Ya, we just did one not too long ago, and RST truck 5speed to 60e, basically the same thing.
You'll need to rewire your trans harness or get a conversion harness, very easy to install.
Wire up the vss, new flywheel, converter, crossmember, dipstick/tube, driveshaft, trans cooler lines and trans cooler, floor shifter (easier than stock column shifter), hook up your reverse lights, p/n clutch switch and other small things. Then get the pcm flashed for the 80e support.

do it, you'll enjoy it!

good luck,
allen

 

Talk to Speartech for a conversion harness and tuning. Their prices are pretty reasonable.

 

I thought that the harness they had was only for the 4l60 to 4l80, or is it the same harness? I can have Rick at Synergy do the tune.

 

Yeah, the gearvendors is $2500. I bet the 4l80e would be cheaper. I believe the trans mount is really close if not the same as the 5 speed/ t56 location.

I have a hard time understanding why you would do it to be faster but that is a totally different conversation.

 

I hear you, I figure that everytime you shift you have to build boost again. With an automatic You build boost off the line (5 psi or more) and you have almost full boost all the way through the run. It leaves less room for error, and I don't want to power shift because I don't think the trans would last for one, two you still lose load on the motor, in turn you have to build boost again. I am not saying that the lag is bad, I am just saying that I think it would be benifical to have full boost all the way through the run.

 

I agree with much of what you are saying but i'm just not willing to sacrifice the fun of the drive to go automatic. But my racecars have always been 4 speeds so i'm a little biased. I guess if you are truely worried about being as fast as you can on the street then you should be working on something lighter weight to start with.

 

You are right again. It is a sacrifice that I am fighting. I keep going back and forth, trying to figure out if I really want to swap it or not. I love the 6 speed, but at the same time you want to perform the best that you can. I don't know what I want.

 

Make sure you have the vacume/boost line hooked up to the blow off valve and have it set as loose as possible to help with the lag time after shift.

 

Yeah, I did that and it did help. I don't think it lags much at all, I just don't like the idea of it having to build boost each gear. I wish I could maintain the load on the motor between the shifts. In theory it should be faster, maybe not.