4L80E upgrade

[usmc81301]

So I finally finished upgrading to the 4L80E transmission and the 242 transfer case. As much as I am enjoying it now, that had to be one of the biggest pain in the a** things I have done yet. Not to mention more expensive then I thought it would be. If you were thinking of doing this I will tell you it is great and worth it when it is over but getting there is just tasking.

I also got it repainted with the water based CARC paint so it is looking good too.

 

[Haasino]

usmc81301,

If you have the time, would you mind posting a brief write-up on your experience doing the upgrade? What the process entailed, what documents you used for reference, what surprises you ran into, what made your wallet lighter, etc? I've been looking into undertaking a 4L80E/242 upgrade, but I'm still trying to get a grasp on exactly what kind of job that would be.

 

[usmc81301]

Yeah no problem. I will gather and write up some papers about all the things I went through tomorrow.

 

[Haasino]

Cool, thanks!

 

[OPCOM]

Please post the story and pictures! It could save others a lot of time and the 4L80 (E or not) is a great transmission.

 

[Haasino]

A basic list of the parts needed (beyond the obvious 4L80E, 242, TCM, and OD Shifter) would also be a great help to those of us trying to calculate what an upgrade would cost.

 

[SETOYOTA]

subscribed

 

[usmc81301]

Other than the standard already know needed parts, here are some others thing I found out along the way.
New engine harness/ New body harness
New shifter and all the linkage from the shifter to the transmission and the transfer case
Engine speed sensor/ Throttle sensor/ Transmission input speed sensor and output speed sensor
New brake pedal switch (it has two switches on it for lights and the computer)
New driveshaft’s (shorter)
Check transmission lamp
1 circuit breaker
The TM’s I used were: TM 9-2320-387-24P which is the main one I used to find the parts and their NSN’s. and the normal TM 9-2320-280-20-1/2/3 Unit Maintenance and a schematics of the wiring from the computer to the transmission.

The installing of the parts was really the easiest part of the whole deal for me. The only thing I had to modify was the drive shafts. Since I did not upgrade my differentials to the new ones and had to adjust for the slip yoke drive shafts to work with the non slip yoke differentials. It was a simple process though. The big problem I had after hooking all this up was that every time the transmission shifted from 2 to 3 it would snap the circuit breaker and turn the computer off. I then went through tons of diagnostics trying to figure it all out. Using the manuals I tested the computer and then went pin to pin looking for a possible broken wiring causing high ohms. What I finally found after many hours was that one of the pins between the transmission and harness on the transmission end was making poor contact making a huge amount of ohms. I was able to correct this but it was a huge pain in the butt to do at this point. What is crazy is that the connector from the computer to the harness is a strong military style connector but the harness to transmission end is more civilian like and less sturdy. One other thing I stumbled across was since I am still using the 60 amp generator, I had to make a wire to tell it when to come on since there is not one on the new engine harness. If you have the newer bigger generators I think you should be ok. Other than that it was basically a simple process. Sorry in advance if I miss anything or it is not clear, I am in Austria and have been for some time now so I am trying to think back. Feel free to ask any questions though and I will try to help as much as possible.

 

[Haasino]

Excellent write-up, thanks!

 

[SETOYOTA]

good write up but did you have to use black text?

 

[popacom]

Don't fret usmc81301....everyone I talk with say's......popacom
your the guy .....writes big and yellow!!!! LOL

popacom

 

[usmc81301]

Sorry I don't know why it was black in th first place. I wrote it and never even thought about it being black.

 

[jwaller]

sounds good. I'm about to do the same swap on mine, I've got the 200amp gen to swap though.


How did you get 12V from your 60a gen or did you just go to one of the + terminals on the batteries?

I'll be swapping to the new style driveshaft when I do mine.

Did you install the RPM sensor on the crankshaft?

 

[usmc81301]

Yes I just tapped into one battery for now. Generators are just a bit to expensive for me right now. Yes I did put the RPM sensor in, thanks for bringing that up. To have the new drive shafts you have to have the new differentials also. I did not destroy my drive shafts, I just made a mod to make them work with the old differentials. When I get more $$$ then I will upgrade more.

One more thing I thought I should mention is that I am running a 6.5TD in mine and I am not sure if there was a wiring difference in the engine harness between the two or not. Just heads up.

 

[jwaller]

would you mind unplugging the rpm sensor and seeing what it does. I'm planning on doing the install but not doing the rpm sensor until I swap to the 6.5T.

I was told that the trans will still shift as normal but without the rpm sensor the converter clutch won't lock up. I'd like to know if that is true or not.

 

[usmc81301]

I can't do it for awhile. I am in Austria and will be until August 1st but I will see if I can get someone at home to do it and tell me what it does.

 

[jwaller]

ok, thanks, I'd love to hear from you about it.