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HD2 kit Update and caution
recently we had a discussion on the sloppy page and people pointed out to me to not perform this mod
"Grady Farrer: It's to solve over pressure conditions. It has you drill from 14 into 47. 47 is a void so it's easy to undo this mod if you've already done it
If torque signal fluid builds up too much pressure (tune. Worn valve. Epc, etc) then it will unseat the trans go ball and exhaust the fluid.
This way you don't build up too much pressure and blow out snap rings or seals etc.
It's a bad mod because if the transgo ball doesn't seal perfectly...or over time it wears out and leaks...or gets cocked sideways etc...then it leaks torque signal fluid and causes horribly LOW line pressure and cooks the trans
It doesn't really fix anything and there's a big risk to break shit. Moral of the story... don't do the relief mod
4.8/5.3 4L80E Swap & General Information
4L80E Differences:
'91 -'96: They are all pretty much the same. They were also known to have a crappy connector that passes through the case. Most have had them updated by now, but there are still some that haven't and might need replacing. They have the ‘older’ style lubrication, where both cooling lines are behind the bellhousing. They also have larger overdrive roller clutch, usually came with a 16 element sprag instead of the 36 element. The bellhouse bolt pattern is the traditional SBC/BBC pattern. These early transmission also did not have mounting holes for the manual lever position switch (MLPS) ie. neutral safety switch.
'94 -'96: These are the same as the earlier ones but with a few differences. It has an updated EPC (electronic pressure control) solenoid. Some also had a longer shift shaft for the MLPS.
'97 - '99: These years have the ‘new’ style lubrication, where there is one oil cooler line behind the bellhousing and the other being farther towards the back of the transmission. Also uses the bellhousing bolt pattern of previous years.
‘00 - ’03: Same as previous years but bellhousing bolt pattern was changed to the LS style.
‘04 - up: Same as previous year with some minor valve body changes.
Gear Ratio:
Flex plate:
You will need a flexplate and spacer from ¾ ton GM truck that originally came with a 4L80E. Your other option is, if you're going with an aftermarket torque converter anyways, is to have the torque converter made with the correct offsets and mounting pads to bolt up to the stock 4.8/5.3 flex plate. Circle D can do this no problem. (https://www.circledspecialties.com/)
GM Part Numbers:
19260102 FLYWHEEL
12563532 SPACER
19257940 BOLTS 6
PCM/Tuning:
If you’re using the factory PCM this is pretty straight forward, just have it loaded with a 80e tune from a Chevy Express 4.8/4L80e or similar.
DIY Manual Valve Body:
Terminal pinout wires "A" and "B" from the pressure manifold are connected together and connected to the ground side of "Shift Solenoid A". Terminal pinout wire " C" from the pressure manifold is connected to the ground side of "Shift Solenoid "B". 12 Volts is supplied to the Pink Wire on the outside of the trans .This will power up the shift solenoids as well as the lock up solenoid. If you want to lock the converter you must run the Brown Wire on the outside of the trans through a toggle switch to chassis ground.
Cooling lines:
‘91 - ‘96 (SM=Straight Mechanical)
‘97 - Up (SM=Straight Mechanical)
Note: They are straight thread without the taper normal pipe thread has. Also on later models (‘97 and up) the rear cooling line fitting has an extended tube that goes inside the transmission, looks like so -
Wiring Conversion:
Tips for building a 4l80e without the HD2 Kit (By Grady):
If you're going to tear the trans down to a bare case and actually build the thing...don't spend your money on the transgo HD2 Kit. The transgo kit does 2 main things...increases line pressure and "dual feeds" the direct clutch.
The direct clutch is used in 3rd gear and also for reverse. The apply piston for this clutch is divided into two chambers. In reverse, it uses both chambers and gets full apply force. In 3rd, it only uses one chamber...significantly reducing the apply area and overall holding power. "dual feeding" the clutch allows both chambers of the apply piston to be used in 3rd gear also...more than doubling the strength of 3rd gear.
To dual feed...remove the center lip seal on the apply piston, remove the 2nd sealing ring on the center support, and plug the case hole to the right of the center support bolt. You can plug the case passage with a 3/8 cup plug driven in. Or you can tap the center support and install a set screw. Make sure the set screw is below flush otherwise the center support won't seal against the case and you'll have a nightmare.
For increasing the pressure, use a sonnax brand boost valve. The "4L80e-LB1" is the part number you want. If making LESS than 1khp...and I mean a true 1khp to the tire...use the valve and sleeve but keep the stock pressure regulator spring. If making more than 1khp...use the included sonnax spring.
Another important area to improve is the intermediate clutch snap ring. The stock ring is flimsy and weak. Use a snap ring from a Torque Flite 727. the 0.106 thickness option usually works the best. if clearance is too tight with the .106 you can step down to the .088
Drill the separator plate. I've attached the transgo plate picture so you can see which hole is for which gear. Usually 5/64" (.078) is fine for lighter cars or lower power units for 2nd gear...you don't need to make 2nd stupid firm. If making some jam or in a heavy vehicle (4k+ lbs) 3/32 (.093) will be ok. 3rd you can go 7/64 (.110) for most stuff and for high hp/heavy go 1/8" (.125) Same for 4th.
Don't take these numbers as gospel...it varries car to car, engine to engine, and person to person. While uncle Jimmith might want to "bark the tires" on every shift at 20% throttle...other guys might not want that.
Bigger hole=faster/firmer shift. If you block accumulators...use the smaller of the hole options because the shifts will get faster and firmer when you block accumulators.
As a side note...replace the electronics and harness. You can usually do this for less than $200. If nothing else...replace the EPC solenoid. It is by far the most important as it controlls the pressure of the trans. So just replace it...don't cheap out here.
Speaking of accumulators...if you want to block the 3rd or 4th accumulators, you have a couple options. The first option is the easiest and most foolproof...just buy an accumulator delete plate from Jakes performance. They're not that expensive and they work great every time. If you don't want to buy one, you can tap the stock accumulator housing and block the feed holes with a set screw. The bore without the pin is for 3rd. The hole with the pin is for 4th. the 2nd accumulator is in the case and does not need to be blocked. Use a 5/16"-18 tap and set screw.
Ideally, you would have the pump and valve body vacuum tested...but I'm realistic...99% of guys in their shop aren't going to do that. SO, just buy the transgo AFL Fix kit. "48-ACT-TL"
The kit will do 5 valve bodies...so save the kit and do a solid for some local buddies or sell the used kit with 4 valves left in it...it ends up being very worth the cost. A leaky AFL will cause HORRIBLE pressure rise, and poor actuation of the shift valves...which means the solenoids might command a gear...but the pressure from afl is too low and it won't move the valve and shift.
Also, in the pump, drill this hole. But use a 5/64" (.078) drill bit. It provides better lube flow...it also keeps the converter from dragging. So, you'll run cooler, have better lube, keep the converter happy, etc.
As a rule of thumb...over 700 horse...get a billet input. Jakes performance has a budget friendly billet shaft.
over 800 horse get a forged fwd. hub...FTI has a good unit at a good price. (if you're building a 400...they have a weaker hub...use an 80e steel hub up until 800 horse...then go forged)
MOST IMPORTANTLY Verify the damn fluid level. Seriously...you've taken the time to 80e swap your ride...you've LS swapped your shitbox, you've loaded a tune from the sloppy wiki...you've done alot of stuff that has taken more time and energy than this...but this can EASILY ruin your weekend when you shit a trans.
Just make sure the dipstick reads correctly. Correct reading means that "FULL" Is level with the pan rail. The flat part of the case where the pan bolts/seals. Right at that level or 1/8" above it the correct fill level. I recommend doing it IN THE CAR with the dipstick permanently mounted. Get the trans in and bolted up to the cross member...then drop the pan and check the stick. Scribe a line on the stick if the existing line is not accurate. It doesn't matter if you get a "madman" or a lokar or some other 200 dollar dipstick...don't assume it is correct...verify it. Honestly this is one of the biggest killer of fwd and int clutches and it's ridiculous not to take the time to do this verification step.
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