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4l80e swap

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Metcalf89

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I'm sure this has been asked multiple times but not sure how to search for it as I am new here but I have a 98 k1500 5.7/4l60e floor shift 4x4 trans is done and im done fooling around with the 60e what year 4l80e can I swap in to it I know its more that bolt in and go but I have to find a trans first and unsure what year I need to get any help is greatly appreciated
 
I think we need a new flywheel for TC 4L80e and trans highstall.
TC sometimes with a long neck and short. depends on the year of manufacture gearbox.
 
Any 95+ 4l80e can be made to work. In all honesty, the majority of these swaps either end up butchered and never work right or get sold once they realize just how much work it really is to do the swap. If all you hace is a 5.7l, even one with moderate mods, there is ZERO reason to swap to a 4l80e. A properly built 4l60e can more than handle the job.

If you're dead set on it, you will need the 4l80e trans, 4l80e flexplate(unless you get an aftermarket high stall converter, then you need the 4l60e flexplate), adapt/modify the cooler lines, either change your transfer case input shaft(4l60 is 27 spline, 4l80e is 32 spline) or get a different transfer case, longer front driveshaft, shorten the rear driveshaft, get a different slip yoke for the rear shaft if you switch to a 4l80e transfer case, drill new crossmember holes in the frame further back, longer transfer case shift rod, modify the trans wiring(repin the trans plug from the 13 pin 4l60e wiring to the 11 pin 4l80e wiring, add in the input speed sensor wiring, and extend out the transfer case wiring), then custom tuning for your PCM to change it from a 4l60e to a 4l80e trans(if you use a PCM from a 4l80e truck I believe you have to also change O2 sensors & plugs as they have a different voltage switch point than the 4l60e O2's do).

all of this work to have less power to the wheels(the 4l80e has more parasitic drag), a 2.48 1st gear vs the 3.06 of the 4l60e, and a .75:1 4th vs the .70:1 of the 4l60e.

Have your 4l60e built up with a stock rebuild kit but substitute a gpz 3-4 clutch pack, ALL new bushings(use the sonnax kit), beast sun shell, transgo hd2 shift kit, 4l70e 2nd gear servo, and a quality torque converter(I've had great luck with transtar). Make sure and flush out the cooler circuit and add in a good sized auxiliary trans cooler. There's no reason a properly built 4l60e won't last behind a 5.7l vortec.
 
I have a 93 Chevy 3500 6.5 tbd tranny were working fine parked truck for 2 weeks batteries went down replaced bat now tranny won’t shift unless high rpm what went wrong
 
Mcdaniel Hl said:
I have a 93 Chevy 3500 6.5 tbd tranny were working fine parked truck for 2 weeks batteries went down replaced bat now tranny won’t shift unless high rpm what went wrong
Click to expand...
Most likely either have a TPS that got oxidized sitting snd is reading off, or a problem with a temp sensor.
 
I am totally new to thetruckstop. I couldn't find where to post a new question or thread, so I'd like to piggy back onto this one. I have a 1991 square body 4X4 Suburban. It's a V2500, so from the factory it's a 350 (5.7) with a 4L80E. I have no OD gear, and already spent over $600 at a local, "supposedly" reputable, transmission shop. Still no OD. Was going to just swap out the tranny with a low mile used one. All I could find is one from a 1994 Silverado 4X4 with a 5.7. What all would I need to change/modify to fit the 2003 tranny into my 1991 Suburban?
 
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To be honest, I have no idea what is or is not working. Tranny shop owner said it was the cleanest fluid he ever saw, when he took the pan off to inspect. Seemingly, no hard or soft part damage internally. Put it back together, test drove, with computer hooked up, etc. No problem found by tranny computer, but no OD. Took it back in and installed new shift solenoid(s) and something else, along with, of course, a new filter, fluid and pan gasket. Paid over $600, still no OD. Took it back to the shop the next morning, explained and the owner said "Sorry, we've done all we can do." Then sent me on my way. The truck shifts perfectly fine in "OD", except that it won't shift to OD gear. When manually shifting, start in low, shift selector to 2nd, it shifts to 2nd. Shift selector to 3rd, nothing happens. Shift selector to OD position, it shifts to 3rd. Still no OD gear.. The linkage is not fouled up, as the shift lever and linkage on the side of the tranny find all positions in the proper locations, etc. No matter if manually shifting or just in the OD position, the shifts are firm and solid, not quite like stage 2, but feels more solid than factory. Engine does not over rev to shift, when in OD position.
 
You need to put a scanner on it and check the coolant temp reading and the trans temp reading's 1st. Sounds like something is inhibiting overdrive. And the 94 trans will not work in yours unless you want to do a 7427 PCM swap, change your drac to a vssb, change your transfer case, transfer case switch wiring, and repin some wires.
 
Sounds easier and cheaper to have my own 4L80E rebuilt. I do not have a tranny scanner and don't know anybody who has one. Not keen on paying a bunch of money to ANOTHER tranny shop just to hook up a scanner and check 2 temps. I don't have the money floating around to pay another someone who probably still won't be able to give me any real answers. Aside from that, I've seen on 2 other forums that a bad or weak throttle position sensor can (on occasion) cause the tranny to "not believe" that the engine rpms are high enough to warrant shifting into OD gear. That and the other (supposedly) likely scenario is that I have a bad torque converter that is not locking out, which causes too low of pressure reading for tranny to shift into OD gear. I'm still puzzled by the manual shifting results (in earlier reply).
 
JonnyB872 said:
Sounds easier and cheaper to have my own 4L80E rebuilt. I do not have a tranny scanner and don't know anybody who has one. Not keen on paying a bunch of money to ANOTHER tranny shop just to hook up a scanner and check 2 temps. I don't have the money floating around to pay another someone who probably still won't be able to give me any real answers. Aside from that, I've seen on 2 other forums that a bad or weak throttle position sensor can (on occasion) cause the tranny to "not believe" that the engine rpms are high enough to warrant shifting into OD gear. That and the other (supposedly) likely scenario is that I have a bad torque converter that is not locking out, which causes too low of pressure reading for tranny to shift into OD gear. I'm still puzzled by the manual shifting results (in earlier reply).
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Why would you rebuild a trans when it very well could be an electrical issue? If the PCM thinks the fluid is cold or that the engine isn't up to temp, you will NEVER get overdrive. That is why you have to scan them. Fully electronic transmissions have to be diagnosed, not parts thrown at. Firing the parts cannon almost always leaves you lighter in the pocket and your problem not fixxed. You need to find a shop that actually repairs things, not just throw parts at it. There was no reason to replace the shift solenoids if you have 1st, 2nd, & 3rd, anybody sho know the 4l80r knows this.
 
I don't know much at all about electronic transmissions, except what I wasted money on and what I'm learning here. Is there any possibility that bypassing a heater core (due to leak) would cause an incorrect temperature reading? Now that I think of it, the tranny started acting up not long after I did that. I've since, finally, replaced the heater core and temp sensor. Flushed and filled cooling system. Had to do all 4 corners of brakes, and now the master cylinder is dead, so I can't drive it yet to see if TPS fixed it. Or... if fixing the cooling/heating system may have possibly fixed it.
 
I also added a heavier duty trans cooler in front of the radiator. The original was leaking, so I upgraded.
 
What type of scan tool can be used to diagnose? Is it one specifically for transmissions only, or will a regular OBD1 diagnostic scanner work?
 
98 is obd2 not obd1. And you need a scanner not a code reader. Code reader is the low cost units that just read & clear codes. The best one for it is a tech2. But there are several others that would work like otc Genesis or the newer version of it, snapon modis, etc. you aren’t dealing with the $150 unit here.

Bypassing the heater core can mess with a sensor or even overheat some engines depending how you do it, but as soon as you corrected it, it would have we t away. You need to do a current reading. Finding a good transmission shop you can trust is probably your best answer at this point. A person can diy transmission repair but it is expensive to tool up for it.

Where do you live? Maybe someone here is near you enough to know a good shop near them.
 
I'm not sure where "98" came from. I know most things about my truck, other than the electronically controlled transmission. I've been a tech for over 30 years, but not a transmission specialist by any means. I know for a fact that my rig is a 1991 (not a 98) and I know for a fact that it is an OBD1 system, not an OBD2. Most techs these days do not own scanners or code readers that will even plug into an OBD1 port. And I was not referring to a code reader. I was referring to a scan tool. My question about scan tool was "Is there a specific scan tool for transmissions only, or will a *standard all around read all systems* scan tool work?". I never mentioned anything about a code reader.
 
Ok sorry. Most everyone puts their truck in the signature line, And when I read the post and it didn’t have yours I scrolled all the way to the top of the thread and read that thinking it was you starting the thread. That is where I got the 1998 from, Sorry for the confusion.

Many of the top end scanners that are bidirectional and can read trans have an adapter cable that can plug into obd1 ports, like the OTC mentioned. Yes it is a pain to find them. My 95 hummer makes it a step worse by being obd2 connection but obd1 software, so yeah i feel for the pain of dealing with older electronics. And like you i was a mechanic but avoided transmission leaving it to the specialist like thefermanator.

It’s been so long since I’ve use a Tech1 that I cannot remember if it has transmission communication.
 
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