Here, we are going to explore the actual hands on steps in our 4L60e to 4L80e Swap in my 2002 Chevy Tahoe 4×4. The first thing I wanted to do was clean out the lines and the trans coolers of any fluid and possible debris from my old 4L60e. I used a bottle of Kooler Kleen (actually 2 bottles as I spilled some of the first one). Next, I got to work on the flex plate. Because I got my torque converter from Circle D and opted for the billet front end, it had the same bolt pattern as my old flexplate. Unfortunately my old flexplate had seen some serious wear and the bolt holes were a little oblong, so I got the new flexplate. If you have a torque converter for a 4L80e with the 6 bolt pattern, you will need to get something like the ATP Z-270 flexplate and the spacer.
Next came the transfer case adapter. Keep in mind, mine is a GM 246, your parts may differ. For mine, you can’t use the one from the 4L60e on the 4L80e. It’s not even close. I bought a AC Delco 15724745 off Amazon and keep in mind that your 4L60e bolts won’t work either because they are too long. You will also need the AC Delco 8681168 Seal and the AC Delco 24245110 gasket.
My 4L80e came with a 2200 stall torque converter that I replaced with my Circle D GM 278mm HP 4L80 LS Torque Converter 3000-3200 stall with billet front end and 3 bolt LS flexplate pattern. I put it in to the tune of 3 clunks and then measured the distance from the edge of the bellhousing to the bolt pad of the torque converter and made sure the distance was greater than an inch. This lets me know that the torque converter is properly seated and I can move on.
Something that slowed me down was not realizing that my 4L80e did not come with a front Vehicle Speed Sensor (VSS) or any hardware at all. All of this needed to be purchased, and resulted in wasted time. I share this so you don’t have to go through the same thing.
At this point, I am almost ready to put the tranny in, but I affix the vent tube at the very top of the transmission first because it’s a pain once the transmission is in the truck. One thing I learned is to put a couple exhaust studs in the engine holes (where a bellhousing bolt will eventually go). I put them at 3 o’clock and 9 o’clock and use them to guide the tranny on to the engine. It works pretty good and they went together without too much trouble. Next is the fun task of those pesky bell housing bolts. I took both front wheels and fender wells out and then the heat shields on each side, (headers were already out) and that gave me easy access to all the belhousing bolts. If you don’t want to go through all that trouble, just get behind the transmission (where you can see them) and use a couple of socket extensions (probably about 3 feet) to get your bellhousing bolts on.
With the 4L80e in, I was ready to take the measurement for my home made transmission crossmember. I put it in to see where the holes would line up, marked them, and then drilled the holes.
Now for the hardest part of the whole thing (for me, at least). Getting the transfer case in there with the 4L80e already in there is hard. Just get under the transfer case and man handle it up in there, tail shaft first, over the torsion bar. I cut a piece of 2×4 the right length and wedged it between the floor and the transfer case when my arms started to feel like spaghetti so I could take a rest and then get back to it. I’m 50 so you might not need to, but I’m not as strong as I used to be.
With the transfer case in, I was able to get to work on all those electrical connections to the transfer case and transmission. I had a wake up call when the shift cable bracket from the 4L60e did NOT fit on the 4L80e. It’s not even close. Had to order GM 15013290 and wait 3 more days to make more progress on this step.
In the mean time, I got to work on my 4L80e transmission oil lines. I decided to use -6 AN fittings and braided steel hose. It wasn’t hard to do and I like the way it looks.
Next came bolting the torque converter to the flexplate. This is pretty easy with an assistant. Have them put a socket on the crank bolt with a breaker bar and hold it steady while you torque your bolts, then spin the crankshaft for you to advance to the next bolt. It can be done alone, but it’s not very fun.
Next came the starter, 2 bolts, no big deal. Then I added a dust cover to the bottom of the bellhousing because I’m used to my 4L60e and felt better with it all closed up.
I purchased one of those 4L60e to 4L80e wiring harness adapter because I did not feel like doing all the re-pinning myself. I still needed to run the line from the front Vehicle Speed Sensor to the pins in the PCM, but that was not that hard.
I’m getting close now. I attached the shift cable to my new 4L80e bracket and got to work on a step that had me worried for weeks prior. … Would the drive shafts fit? I was surprised, as both of them worked perfectly.
Then went in the headers, and the y pipe, all was well in the world. Next was the transmission dip stick which was easy and I felt like I was well on my way to doing a segment swap and driving my truck for the first time in weeks.
Unfortunately, my last task before tossing the battery back in and doing the segment swap was to fill the transmission with fluid and at about 7 quarts, it started leaking from the pan. Loosening and re tightening the bolts didn’t work. No telling why – could have been damaged in shipping, or I could have done something to it when supporting it with a jack. I’ll never know, but what I do know is that the guys at Transmission Depot were amazing and they are shipping a new pan and gasket to me no questions asked. That’s great customer service!
Keep an eye out for at least one more video in this series. I hope it’s just a quick segment swap and I’ll be turning the key, testing out the new 4L80e and getting ready for what’s next ……….. a turbo!