98 Fbody 4L80e conversion and install
Not sure who left it off of the ATSG diagram but that was an oversight. This Sonanx image on the 34200-14K product page is correct.
None of this has been cleaned, it was this clean taking it apart!! i had a slight amount of dirty oil in the accumilator housing but that was it. everything else is fresh. seals, bearing, clutchs, steels... I mean other than the HD2 parts and the new lube valve, nothing is cleaner than it is right now.
You can get this tool to compress them if they don't air check well and you suspect a blown seal:
Only use 40 PSI of air to check the clutches so that you don't blow out the seals. Can even fill the 4th clutch with fluid, cover the weep hole, blow air, and check for leaks.
Got a pump install clamp, all of $12. highly recommend this little guy so you can line up the two halves of the pump. was fighting the pump trying to get it on and finally realized that the pump wasn't lining up. once I did that, slide right in, actually better than before I took apart the pump.
everything is back together. put a new pump gasket and input shaft seal on before buttoning it up. torqued all the bolts and put all the electronics back in place.
still gotta get a yoke and a mount since this ones pretty much gone lol im not sure what my current mount looks like yet but i belive its the original rubber mount, so probably time for a new one. pretty cheap replacment anyhow
also partially finished up the repin. i know its a mess, and i still need the 99+ pcm bucket to hold it properly, but its in its place kind of for now. thw wiring i was gonna clean up once i get it running and know i repinned everything properly.
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Side by side view. same length, seems to have a bit more barrel travel than the stock
inside is counter bored
Last edited by JoshuaGrooms83; Sep 1, 2022 at 06:41 PM.
new spicer stock style ujoints. just trying to keep er moving, and update the 20+ year old stockers on the stock drive shaft. when i get a 12bolt or 9", then ill upgrade to some 1350s with a newer driveshaft, and sonnex yoke.
got a stock style bushing. cheap and easy for now. Ill look more into poly or solids later, but for now its a street car, so im not trying to rattle all of my teeth out yet lol
id say the old one is pretty much KIA lol
New spicer ujoints on the stock shaft and the new Dennys yoke.
Got a ujoint puller, best $45 ive spent lol
yanking the old 98 ujoints. cant believe they held on this long lol
side by sides of ujoints and yokes
old yoke was pretty close to being done
id say the new yoke is pretty beefy compared to the old ls1 yoke
All buttoned up and ready to go. The steel shaft apparently is the way to go anyway lol ive heard a lot of people go back to a steel over the aluminum shaft.
finally got the 4l60 out. now to do some minor cutting to get the 4l80 to fit.
Almost on the down hill of the swap.
got it on the ground. if anyone needs a core, i got one. most definetly gonna need a rebuilt from the bottom up
old revmax 3800, will need a rebuild as well if anyone wants it.
Always at least one casulty lol on the last converter bolt, my wobble extention sheeter off. Almost rounded the arp bolt, but manged to get it with a 1/2" drive socket verses the 3/8.
Don't even try to run a low dollar pressure sensor out of that pressure port without using a 90 degree adapter lol. Without it, the sensor sticks out even more than the main harness plug.
Put the new ls to 4l80 flexplate and some new arp bolts.
and started cutting the trans tunnel slightly to fit the wiring. glad I didn't completely put up the new pcm harness, case I have to go back into it to pin in the front input sensor.
Gonna see if i can make my stock dipstick tube fit, but i think im gonna need to get the Jakes or Madmans fitted tube. Just dont like the look of the locar flex tube and i dont hear good fitment with them either.
old ls1 flexplate, wasnt too hard to take out. suprisingly the rear main seal isnt leaking. still gonna replace it for cya
Also... pay no attention to the VA tags LOL
not a bad tunnel... be a shame if someone hacked it up lol I marked where I'm gonna cut. there's some tack welds I'm gonna have to drill out though.
new 4l80 to ls1 flex plate with spacer and longer ARP bolts
silly bolts, get in the tunnel.
Flex mounted for verifying fitment. slides right on with no obstructions and the arp bolts thread just fine. zipped them down temporarily for now. I wanna replace the resr seal and install a new oil barbell.
Our tool of choice... I know,i know, its not a milwaukee, Ryobi will have to do lol
Wired in the input sensor wire to the pcm on the newer 99+ PCM, notched the tunnel for a better fit, put some banjo fittings on the trans, matted stall so it doesn't go bad 😉 j/k, and finally laid down the trans and mated the tail housing to the trans and the new rubber bushing. still need a dipstick tube and a nut for the mount bushing since the 4l60 is different and I don't have one laying around.
pretty straight forward. just plugs right into socket 22 and 23 in the red pcm harness for the little pigtail. the big one is for the 4l80 to 4l60 harness.
Took a little wirth with a drill, sawzal, and eventually a cutoff whell but it came off. Smacked a bit more room under it with a ballpeen to clean a little more room incase I needed it. Deburred and touched up the raw metal with some red spray paint under it to keep from rusting. might have taken a little metal off the under metal, but i can patch that up with some spot welding later.
a tail of two trans... lol got the old one next to the new one makong sure i have all the ezternals i need to go on. i had to take the shift conncting ball/lever of fthe 4l60 since the 4l80 has a small ball on it. from what i hear the exisisting shift bracket fits and works on the 4l80, but i have the old hardware off the 4l80 is i need to modify anything. i guess i dont need the electronic thing thats on the side of the 4l80, so i took that off.
finally got off my *** on a nice day today and shoved that thing in. measured the FTI stall distance from the pads to the face of the bell housing and got an 1 & 1/16th" distance after fully seated. Followed Jakes video to make sure I did it right. got the new umi mount up and the bellowing bolted up.
Im so glad i cut off what i did, the 4l80 fit perfectly and a few love taps here and there to clear and nothing is touching. the banjo fittings were a great choice too. The harness fits nicely. only thing I noticed was that the near ISS input sensor harness is long and the original rear output sensor harness is very short, almost couldn't plug it in without having the trans in place. I double checked the diagram and it shows that input sensor pigtail goes to the front. I hope I have this right. really do t wanna try and pull those out lol
Got a little dark this evening so I'll have to take some picture this weekend. ill get either madman or jakes dipstick tube. I wanted to try and use my original tube, but after trying to bend it a little, not worth the effort for the price of a new one.
Still gott hook up the shift linkage, stall bolts, and the inspection cover. After that its down hill. the hard part of getting that trans up off the ground was the hard part lol
https://drive.google.com/file/d/1Po8...ABgM6gNun/edit
Are you able to get a mechanical pressure gauge on the pressure port with it installed? Check out page 3 for AN adapter fittings to make access to getting a pressure gauge on it easier and if you want to run a transducer on it also to log the pressure. Shift linkage removal makes it easier to get to.








