JetForceF22

Hello Everyone, I'm just new to this site seeing that my 4L60-E Transmission just gave up on me today. I lost Third and Fourth gears, so the truck now maxes at 60 in second. I knew it was only a matter of time, I felt the transmission slipping recently.

As the title states, I have a 1995 K1500 Silverado 350 5.7L TBI with the original 4L60-E (280,000 miles) And original motor, with some modification (look at my signature for more details). I would like to know what parts I will need in order to make this swap, with the performance mods I have on my truck its pointless to put another 4L60 back because I know it will just bust, and I know the 4L80 is a much more reliable transmission.

I have been looking at the various threads, and see that this swap is pretty popular, I just want to know what I need in order to get this done correctly. As stated above I have the last year throttle body motor, and the 95 is the first years they introduced the PMW Lockup converter, (I think its approx 2300 stall?) so I'm fairly certain that I have that as well.

Any help is greatly appreciated! Here is a picture of the truck, and some of the transmission pan.

GMCtrk

iTrader: (27)

PM oldred95....he did the same swap in his 95

JetForceF22

Alright thank you

howard quick

You will need the larger input shaft for your Transfer case and maybe have to fab a new crossmember. You will also need the shifter cable bracket that bolts to the side of the 80E (60E won't fit). You will need the transmission to t/fer case adaptor. You will need to make a couple of wiring changes and the PCM will need to be tuned to suit.
Tailshaft will need to be shortened. You will also need the 80E dipstick.
Best/cheapest way...in my way of thinking is to buy a complete, second hand 80E from a K2500 with t/fer case, tailshaft and as many bits as you can get.

oldred95

Here's the deal. Your biggest decision, at least my biggest decision was on how to control the thing. Basically you have two options. You either get a PCM from a 350/4L80E truck and then add the wires for the Input Speed Sensor (which I'm told you will need for 4 low operation) or dive into Do It Yourself tuning and stay with the 350/4L60E program and turn a bunch of crap off such as the 3-2 and TCC PWM solenoid diagnostics so that codes don't set. You would also have to input the correct trans ratios and modified shift points and TCC settings into the 4L60E program like I did to make it work in this way. Also using the 4L60E programming you will need to install a relay inline on the shift solenoid B circuit to invert its signal. Shift solenoid B works opposite 4L60E to 4L80E. Also the 3-2 solenoid wire needs to be pinned to a dumby cavity in the connector along with the PWM wire.


Now then on my 2wd it was basically a direct swap aside from the cooler lines and having to change my exhaust a little. I was even able to keep the stock driveshaft, only doing a yoke swap for the bigger 4L80E output shaft. In your case you will need either a transfer case from a truck with a 4L80E or just the transfer case input shaft from a 4L80E truck. I'm not sure on the cross member but I would imagine the holes are all there and you would just need to slide it back. Then change your driveshafts accordingly. Really its not a bad swap mechically speaking but the biggest problem on the OBS is figuring out how you want to control it.

Two other options are you can go with an aftermarket stand alone transmission controller but they are big money. The other option is you can make a TCM (transmission control module) out of a 16197427 (that would be your PCM). Basically you have to provide it with power, ground, vehicle speed, engine speed, MAP and TPS readings and then disable all engine related diagnostics and so on. This will then provide it with the needed info to control the transmission and then just run your wires from it to the transmission. You would have two PCMs then, one controlling your engine and then one thats acting as a TCM to control the transmission.

JetForceF22

Great, all this information is a big help, If I do decide to do this swap though it may be a little bit over my head. My other alternative is to spend about 10k on a new engine/transmission and a new gears set and drive shaft. Either way I really am trying my best and I don't have the money to afford either, its only a matter of time however before the engine gives up is my thoughts, so it might be worth pulling a loan to get the job done right, I haven't made up my mind.

I thank everyone for all the help you have given me thus far

oldred95

For no more power then you are making a properly setup 4L60E should do just fine. They can build them to live in the 600 hp area if not more and it would make life a lot easier for you to just bolt that in. A 4L80E swap on a 2wd is no big deal but its a different story on a 4wd. On my 99 if my 4L60E ever goes out I'll probably just have to do a mild buildup on it since I'm not willing to sink a few grand into a 7000 dollar truck that I really don't like all that much. On my 95 the whole swap cost around 650 dollars at the most. I got the 4L80E in good used condition for 350 bucks out of a 96 one ton so I couldn't go wrong there.

JetForceF22

Well no you certainly cannot go wrong there, I just wish I had some money so I can overhaul the truck the way I would like too.

JetForceF22

Hello everyone, One year later and I'm having transmission issues once again.

I ended up getting my 4L60e Rebuilt, wrong decision, I am having OD slipping issues going around turns, the torque converter doesn't stay locked and goes in and out of locked mode.

I'm seriously looking at this swap again, and now that I have a better clue on what I am getting into, I had a few more questions.


Will the transfer case need to be moved? I don't know if the length of the 80e transmission is actually longer then the 60e.

If the xfer case is moved back... how is it going to be bolted in? And I'll have to get different driveshafts as well (I'm assuming, just need some confirmation)?

I have read that the transfer cases in the half tons were NP241 transfer cases, and to my knowledge that is the same transfer cases used in the 2500's as well. Will the 4L80 bolt right into my existing transfer case or as OldRed95 said I need to get the "transfer case input shaft from a 4L80E truck"?

If I got another transfer case from a 80 truck I should get the driveshafts as well I'm assuming?

Whats the deal with the cooling lines.. I know that they need some modifications (lengthening?) to fit but are the threads the same from the 60 to the 80?


Going back and reading this now after a year of accumulated knowledge much more of this thread makes sense to me know, and I'd like to thank everyone who previously have given me this valuable insight to this swap. Thanks in advanced everyone.

D15L

the 4L60E is a 700r4 that has electronics to it. 700r4 was put in corvettes years ago, change that trans to a 700r4 and it will be fine.