Cucv M1008 4l80E swap

lukeM1008

New member
8
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Location
oregon
I realized for me to drive my cucv around a lot and for it to be practical I needed an overdrive. I looked at a lot of options such as nv4500, gearvendor, ranger+sm465 but I found the easiest and probably the cheapest swap for me was going to be a 4l80E. Right now I have most of the parts I need to do the swap and I have spent about $875 but I still need to get the rear drive shaft shortened and front one lengthened. I found a deal on facebook marketplace for a 4l80E, np241, and a seized 454 all for $200 so I bought it and then sold the seized big block for $120. I pulled the pan off the 4l80E and it looked really nice inside and the fluid was not burnt so I put a new filter in it and I am planning on using it as is. I also am going to try to use the torque converter that was on it because it is probably a low stall one. Since the 4l80E is electronically controlled I needed a stand alone kit to control it so I got the Painless Performance Perfect Torc kit. I went with the Perfect Torc kit because it was the only kit I found that didn't need a tachometer input from the engine I also had to get a throttle position sensor for the stand alone computer to work so i got a acdelco one made for the 6.2 diesel and it just bolts on the injection pump where the vacuum valve for the th400 shifts used to be. my plan for the trans cooler is to use the stock in-radiator th400 one because i don't plan on hauling heavy trailers in hot weather and it will work out nicely because the 4l80E i have is the earlier one with the cooler line ports both in the front so they should be able to use the th400 cooler lines. In a couple days i’ll commit to pulling the th400 and post more about drive shaft length, the cross member situation, and shift linkage. IMG_4610[1].JPGUVOB7537[1].JPGIMG_1330[1].JPGIMG_1332[1].JPG
 
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lukeM1008

New member
8
10
3
Location
oregon
Killer deal! I found this that may help you id the TC. I have heard that they can be the same but then again, better safe than sorry. Good luck!
Thanks for the info but I couldn’t find any numbers or anything stamped on my tc so I was just going to take my chances.
 

cruzer747

Active member
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Location
California
Thanks for the info but I couldn’t find any numbers or anything stamped on my tc so I was just going to take my chances.
no fins cast onto housing as described in pdf? The angle is supposed to let you know low or high stall.... (looking at the hub swirl counter clockwise = low and clockwise = high... just in case you missed hat bit and for anyone else who digs this up later)

Just noticed you have a goodwrench sticker on there so my guess is it has been replaced at some point.
 

lukeM1008

New member
8
10
3
Location
oregon
no fins cast onto housing as described in pdf? The angle is supposed to let you know low or high stall.... (looking at the hub swirl counter clockwise = low and clockwise = high... just in case you missed hat bit and for anyone else who digs this up later)

Just noticed you have a goodwrench sticker on there so my guess is it has been replaced at some point.
oh ok thanks I missed that about the fins and yes I believe the transmission was rebuilt or replaced recently because it looked pretty good inside
 

lukeM1008

New member
8
10
3
Location
oregon
no fins cast onto housing as described in pdf? The angle is supposed to let you know low or high stall.... (looking at the hub swirl counter clockwise = low and clockwise = high... just in case you missed hat bit and for anyone else who digs this up later)

Just noticed you have a goodwrench sticker on there so my guess is it has been replaced at some point.
I just looked at the tc it has the low stall pattern of fins so now I’m sure it’s low stall thanks again for the infoE60D05EB-7F85-46CA-A092-8B79CB9AF346.jpeg
 

lukeM1008

New member
8
10
3
Location
oregon
I welded some square tube to the cucv crossmember and used some 1in spacer between the trans and the rubber isolator. the turbo 400 dipstick worked with only one bend at the very top to get it more pointed forward
5A1D709C-CD4F-441D-A7A4-EA4B69680DCB.jpeg1B306B51-2E7D-493B-9186-A4FE67631BB1.jpegC872DB5B-7C82-4013-B96E-75F65A5AC0C9.jpeg
 

lukeM1008

New member
8
10
3
Location
oregon
Why the cross member mount square tubing? Mine bolted on without issues. What are your rear drive shaft angles now?
The th400 tcase adapter is like 4in taller than the one on the 4l80e. so the 4l80e+1 in spacers+The square tube +the rubber isolator made it the height of the th400 adapter. the drivshaft angles are exactly the same as when the th400 was in it.
 

lukeM1008

New member
8
10
3
Location
oregon
2EF2704E-2C5B-461D-B2A5-D0FE7A230480.jpeg037AF662-0481-4B89-BA22-AFB733BC1B4A.jpeg776B4C4F-77E3-4506-98C3-08D41383A03E.jpeg2A509A13-400C-4932-9D6A-A65919EA21A4.jpeg
Sorry for the wait. I did all the little things like wireing, linkage lengthening, and cooler lines while I waited for my rear drive shaft. I got it shortened exactly 2 inches and it cost me 200 bucks. The truck is driving now and it cruises over 55 no problem. I used the diesel program on the transmission controler and just set the shift points down so it shifted sooner and smoother. I waited to do the front drive shaft because it was going to cost over 500 bucks so I’ll figure out some way to lengthen it myself and post about how that goes.
 
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