manual 4L80E questions

[K5dreamer]

hopefully this will be a quick question.

some of you may know im toying with the idea of a 4L80 swap in my truck, but i dont like the idea of a computer on my rig, but love the idea of a lockup converter.

Ive found a manual valvebody conversion for a decent price, that eliminates the need for an $1100.00 controler. so ill have to manually shift the thing, whatever, im ok with that.

so heres the question, i know with the 700R4 and 4L60 trannies, you can cross two wires and get the converter to lock up, and alot of guys wire in a switch to lock up the converter on the highway. I am unfamiliar with the 4L80 wiring and was wondering if there was a simple way to wire a switch up to the 4L80 to lockup the converter after the computer has been eliminated.

 

[K5dreamer]

*bump*

i found this image of a 1993+ connector for the 4L80E on the internet.....

http://www.jsm-net.demon.co.uk/trans/index_html_29ba2fea.jpg

according to the chart under the image...

the E pin, is a 12v source, and the S pin is the "LU Sol Switched Gnd"...

yall think its safe to say, that if i ran a toggle switch wired to those two pins on the connector, i could manually engage the lockup converter on the highway? by wiring it through th brake switch, the converter would automatically unlock when i applied the brakes. the same way people have wired up 700R4's in the past.

 

[K5dreamer]

this one seems to be right out of a service manual...

http://i3.photobucket.com/albums/y63/cjperry/4L80.jpg

 

[K5dreamer]

also, it might make sense to wire a contact switch so that when the tranny is shifted into fourth (OD), it automatically locks up the converter, then when i shift out of fourth, the switch is released, and the converter unlocks. i cant really think of when id want to be in overdrive without the converter locked, so that sounds like a good idea to me. that way i wouldnt have to remember to flick a switch all the time. any thoughts?

 

[dyeager535]

Can't help with the wiring theory, I've got two pages out of the '91 R/V manual though if you want to take a look. They are in here, labeled 4L80E. I scanned them huge, selecting full size or download you will have no problem reading them.

http://rides.webshots.com/album/561036416UNTMMP?vhost=rides&start=12

 

[K5dreamer]

hey thanks for the pages, that kinda stuff is awesome to have on hand. looks like its the engine side of the harness, and i dont see anything labeled L/U or anything.

thanks for postin up though

 

[dyeager535]

As soon as I can get it uploaded you'll have the TCM pinout. (pg2 already uploaded is the TCM side BTW, not the engine side) Obviously not the same as what you posted, GM has A,B,C, and D for terminal blocks, while each cavity is a number. No "LU" either, TCC.

Done. Same link as above, 4L80E TCM pinout is the title. That is for the diesel version obviously.

 

[CUCV2]

Mvb

Just a word of caution. I was thinking of doing the manual 4L80E conversion too. After a search (or 2 or 3) I decided the stand alone computer (TCI -$900) would be a better choice for these reasons:

1- Smoother shifts. It has been reported by others w. the manual valve body that the shifts are way harsh due to full line pressure at all times. IIRC this is a 4L80E characteristic and it makes driving it less fun.

2- Installation of the manual valve body is tricky and may take more than one try to get it right. Installation cost plus the manual valve body cost can add up to the stand alone computer in a hurry. Especially if this is a DD.

3- Shifting on the column just sucks in my book. I thought about a floor shifter but that only gets you closer to the stand alone computer price.

4- After weighing in on all of this, I realized I just want a normal shifting vehicle. The stand alone computer allows the tranny shifting to be tailored to suit the driver.

Summary- The OD is nice but pricey. For the money you can do a few other things to make up for it or just go out and get the rig that already has it. This my .02 cents. Hope it helps.