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So I see alot of sporadic or older posts on this topic, and I hope I can help narrow down the searches array a tad since this topic has been around for over 20 years. Some stuff that was put out is either a bit dated and need some refreshing or pictures or links that no longer work.
My specific build is a 98 trans am, SBE LS1 with a Summit Stage 2 turbo cam, CXracing turbo kit, gt45 turbo, 80lbs injectors dual racetronic fuel pumps with true return system,
that was being limited by the 98 PCM and like many of us the limitations of the 4l60, that the turbo system happen to be beating on.
This was a build i kinda got stuck with after I did a cam and griffin rad install, and after dialing in the idle, foud that i had 4 neutrals in my "built" 4l60e. So after some careful consideration, 4L80e and a PCM repin was the real correct answer. All this and still sitting on the original 1998 10bolt lol
Currently I'm in parts acquiring mode. I either have or will have soon:
1996 4L80e 2wd with a bolt on yoke $600
Dennys conversion counterbored yoke $143
new spicer stock ujoints $50
FTI 3600 billet converter $900
LS1 to 4L80e Flexplate $150
4l80e adaptor harness $100
UMI 4l80e trans mount with torque arm bracket $269
4L80e ls dust shield $130
TransGo HD2 kit (minus pressure relief mod) $120
Sonnex line lube valve $40
new trans mount bushing $8
411 PCM preloaded w/turbo cam segmented for the 4l80e $170
99+ PCM bracket $50
Jakes 4l80 dipstick for fbodies or something similar $80
spare red and blue pcm harness plugs $20
I have HPtuners and can tune it myself, as well as Bluecat to aid in the regearing and adjusting for the new shift parameters that will be present.
Here's where I'm at so far. My baby waiting to be worked on New trans mount and FTI converter inbound from Summit took the tail housing off to see what kind of output shaft i have, as well as see what kind of yoke i need the big bolt that holds the yoke and the little ones hold the tail housing the bell on older 4L80e pre 97 have ears and a lifting hole that needs to be cut off. pretty striaght forward Another look at the front of the 4L80e, this one can be told apart from newer ones by the lack of top bolt. nice and clean cuts to install easily install into the tight spaces of the fbody A tag im not sure what it is for yet lol some part numbers The new flex plate and new arp bolts. new adaptor harness 411 PCM preloaded for my car. ill have to tweak some stuff for my specific car, and I need to find out how to segment swap thw 4l80 information new pcm bracket. i wanted to get the BMR or something simular but not sure which one is the right one so stock it is for now. new fitting, but im not sure ifni can use the long fittinf on this trans mission. i got the regular 6an fittings and the banjo fitting for clearance but we will see. i have 6an lines and fittings already on the 4l60 so nothing to change there. coolant line locations on older cases, they are next to each other simular to to the 4l60 the linkage and plug in side, more on this later
Last edited by JoshuaGrooms83; Sep 13, 2022 at 09:56 AM.
Reason: updated prices and parts
today I started the tedious part of repinning the the 98 to 99+ 411 pcm. so far so good. instructions are pretty straight forward. I also learned today that my PCM was already loaded with 4l80e segment, so that part is good.
gonna have to figure out how to re-register my car on HPtuner to my new computer without having to buy a bunch of new credits.
Apparently I got the wrong pcm bracket lol too bad, cause I kinda liked it. I gotta get the 99 to 02 pcm bucket, not whatever the one I got lol
Stock 98 pcm coming out. if anyone needs a 98 speed density 2bar operating system with a partially tuned stage 2 turbo cam on 80lbs injectors with A4 lol i got one lol heres the part number after i yanked it out the pcm bracket that fits the pcm but bot the cars stock locations.... so yeah... theres that. oh well, it was only $30 the new 411 pcm waiting to go in and the specs card one plug done, and working on the second page on the second plug. i bought a spare set to make the switch easier. man am i glad i did. i couodnt imagine tagging every pin, then yanking them, then finaggling them to some where, and then fighting a bunch of snakes back into the new slots lol thia makes it easy and you litterally juat go from one in order down the line and once its in there its in there. this MRK instructions are a life saver!!! could you imagine the cowboys back in the day trying to figure this out before this?!?! props to them guys lol
What were you thinking in terms of a trans cooler and lines?
I've head good things about the Tru Cool 40k LPD47391. I'm probably going to go with that along with some 6 AN, 5/8-18 in. Inverted Flare fittings like 991947LERL or similar along with a Evil Energy 6AN PTFE line kit KT00615AN6BB off amazon to make it all work.
If I can get my new 32 spline yoke to work on my existing driveshaft and still have 3/4" worth of slip that would be great, but being that I'm running a fully splined output (5.25" spline length) and a yoke with a barrel length of 5.380" it's probably not going to have enough slip.
If that's the case, I'll just get the car how it would be if it were sitting at ride height, take the yoke off, bottom it out on the output shaft, pull it out an inch, and measure center of U-joint to center of U-joint and give that number to the driveshaft maker, informing them of how the measurement was taken.
I'm running an aftermarket shifter with aftermarket shift linkage, so I think the longer style shift lever in there will be OK and not create any clearance issues. Shouldn't have to switch to a short shift arm. Clearance seems fine based on this picture of someone's install:
Every car is different as these cars weren't exactly built to the highest spec tolerances. This is why some say certain K-members or headers go on with no fitment issues and some say they don't even though the 2 cars being compared are exactly the same year/model with the exception of the build date.
What were you thinking in terms of a trans cooler and lines?
I've head good things about the Tru Cool 40k LPD47391. I'm probably going to go with that along with some 6 AN, 5/8-18 in. Inverted Flare fittings like 991947LERL or similar along with a Evil Energy 6AN PTFE line kit KT00615AN6BB off amazon to make it all work.
If I can get my new 32 spline yoke to work on my existing driveshaft and still have 3/4" worth of slip that would be great, but being that I'm running a fully splined output (5.25" spline length) and a yoke with a barrel length of 5.380" it's probably not going to have enough slip.
If that's the case, I'll just get the car how it would be if it were sitting at ride height, take the yoke off, bottom it out on the output shaft, pull it out an inch, and measure center of U-joint to center of U-joint and give that number to the driveshaft maker, informing them of how the measurement was taken.
I'm running an aftermarket shifter with aftermarket shift linkage, so I think the longer style shift lever in there will be OK and not create any clearance issues. Shouldn't have to switch to a short shift arm. Clearance seems fine based on this picture of someone's install:
Well before I knew that my 4l60 was a soup sandwich, I installed fittings and 6An lines to clean up and get ride if the old hard lines that no longer requires so much traveling aroundnin the engine comparment lol
Heres the current lines on the 4l60 which will cross over to thw 4l80. heres the current cooler for now, but yeah im thinking of getting a bigger one here was the mess getting the old lines out lol and the new one waiting to go in this is B&M cooler. i forget the model # but its the 7" x 11" cooler. it did the job with the built 4l60, but i think ill get a bigger one later.
lol I keep getting that lol I'm a bit hesitant to install it now.
Today I finally, with the assistance of my 17yo son, picked it up and set it on a spare flexplate and 5 gallon bucket. the hard part was actually getting it up off the shipping rack without spilling oil every where. the fluid was actually really clean.
got it up on the bucket and flexplate... holy crap this ujit is heavy lol all the ones i use to work on with HMMWVS, i never had to pick one up by hand before lol provably should have taken the TC out to reduce some of the mass lol looks like i might replace the pan just in case. draining nicely now. input shaft doesnt appear to be damaged. those of you with more keen eyes, see anything out of the ordinary on the pump or shaft? took off the brackets, sensors, ad what ever the module is for. not sure if i need that. an overview of the input shaft took out the cooler fittings all the external stuff
I was actually looking for that video! I'm thinking of doing that now.
as I took the pan off and started looking at the interior, there almost no discoloring in the transmission fluid or any film on the pan or filter. Almost tempted to not tear it apart lol
As for the Trans go, I've seen several instances where people use part of it, but not drill what it says, and only install certain parts along with rebuilding it.
Full rebuild, detailed and explains nicely what things do. Love the indept yet down to basics instructions, and even how's how to do it like most of us will in our garage.
Transgo hd2 specific without the pressure relief drill8ng or plate. Actually shows in detail specificareasto watch for and other things to leave out or include.
Videos are nice, but I always take the word of a professional builder over what I see in videos. There's a HUGE difference between a builder, and what I would consider a parts assembler. I am NOT a builder. I can watch all the videos, buy all the parts I'm told to buy, assemble per ATSG specifications, incorporate drill mods and still mess up. Why? Because I don't do this for a living and build 100+ transmissions a year. A builder has that experience. These guys develop their own parts for these transmissions to make them better, and that only comes with years and years of experience. An ATSG or a video doesn't tell you things like:
-Check the ramps that a sprag makes contact with and make sure they are not pitted out
-Check to make sure than the underside of pressure plates are level using a straight edge
-Inspection of various hard parts and knowing what to look for to determine if a part is going to fail soon... and many other little things that I can't even begin to pretend to know.
Now the good thing is that the 4L80E is one hell of a transmission on it's own, so we all know its possible to build it as a DIY'er and have great success. I think you'll be Ok going with what is recommended in those videos regarding the HD2, but as previously stated, there's certainly other ways to do it.
I comlletely understand you postion, and yes if 10 years ago if you aksed me if i k ew what i was doing, i say absolutely not lol
However, today I'd say I'm a bit more advanced then a DIY. I actually am a work lead at a shop, and have had some experience in not just repairs and services, but some fabrication and building experience. I will say my internal transmission building skills are a tad novice compared to my other skills, but im pretty confident I can build a 700hp capable 4l80e with a few tried tips and tricks from those who's jobs are specifically transmission internals. With this, slow is smooth, smooth is fast 👌
As for the transmission, i feel like i might have scored a really lucky break.. It seems like I might have gotten a remanned unit out of the 96 donor truck. . check out the inital tear down.
took the pan off, nothing exciting here. everything seems to be in place and nothing missing or damaged. pans actually really clean nothing too different here. after the vavlebody off. check ***** had me a little panicky lol pockets arent too bad. still round old plate, nothing exciting. took the accumulator off. came off, had stock springs initally did the inital HD2 mod, skipped step 1 no drilling. looks like this one was not modified, and is staying that way. heres the new plate. drilled to 1/8 sonce i have a 3600 stall heres where i gotta wait until the lube to liner comes in the mail. Sonnax 3420014K Pressure Regulator Valve Kit, https://a.co/d/ji0Oveo vavle body put back together. no drilling. so i pulled the first drum and planitary. really clean no scoreing, no scorch marks, no debre. Shaft looks good, appears to have new seals. no chewed up splines, no clogged holes, no hot spots. teeth look good. no shaving or other abnormal wear. Planetarys seem like they might be new. pump bushing is newish. no scoring, hotspots, or wear marks. i mean these look almost fresh. this is where i belive this might be a reman. the clutches are are clean, still looks nearly brand new. the top plates also seem to be in good shape to. At this point, im considering not to go any further, and just work with what i have.
Looks pretty damn good but since you have it all apart I would still check the AFL and TCC bores in the valve body and check this forward drum for any scoring in the sleeve:
Also recommend verifying that the reverse servo pin length is good, sometimes they need the tip welded to make them longer to get proper amount of travel.
I would put it back together and run it, glad you decided to go with a 80E!
im giving it a sec while the new line to lube valve comes for the pump.
I buttoned up the case. not gonna risk tearing anything or damage something in the process of checking anything any further. it would be my luckily tear or rupture a lip seal or further down the case without a replacement parts.
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98 Fbody 4L80e conversion and install 
