4L60 to 4L80 help

[Sully]

I'm not sure my tranny is pooched or not, but I dont want to mess around with fixing parts here and there. Its my understanding the the 4L80 is damn near bullet proof. So my plan is to swap trannies.

I am going to try and find a used tranny, but I dont know what they were in. I know they were in the 1 tons, but what years is my first question.

I know the output shaft to the transfer case are different. So my second question is can I use the transfer case from a 4L80 truck? I have the push button 4x4, and would like to keep it that way, but I can adjust as need be.

The article that was copied and stickied says you need new drive shafts according to your lift. Does this mean that stock height can use stock shafts? I plan on going with dana 60's down the road and if I need new shafts, this is going to be a double header cause I'm only buying shafts once. No sence doing it then having to redo it.

My next question is the transfer case compatability of my wifes 95 C1500 with 4.3 and my stocker. If I can give her my drive shafts and torsion bars and everything else out of my front end, then can I also give her my transfer case if I swap to the case from the 4L80?

The long and short of my plan (if I can make it work) is that my 97 will get a 4L80 with dana 60's front and back, and my scraps will make the wifes 95 a much more robust truck.

 

[Sully]

my 60 is dead..... bump for help on this swap

 

[Sully]

found this on the hptuners forum. It might help others doing this, or maybe someone can help me and correct some of it

Here's the list:

Just a note about trannys (disregard if you already know)
The 4L80E transmission is normally equipped with an internal reluctor ring on
both the transmission input shaft and output shaft. The computer takes both of these readings for the proper shifting and operation of this transmission.
The rear reluctor ring is not always installed into the transmission. The basic rule of thumb is 4WD transmissions up to 1996 should have a rear reluctor ring in the main transmission case. All 2WD transmissions should have the rear reluctor in the main transmission case. The 1997 & newer 4WD 4L80E transmissions have a sensor provision; however, the reluctor ring in the transmission is left out. To have this transmission operate correctly the rear reluctor ring should be installed into the transmission case.

Ok on to the conversion.....

1) Modify the cross member either: 5 1/4 or 6 1/4 inches back. Depends on the application.

2) Modify wiring harness 1) VSS (rear) 2) main connector. Use the Speartech performance one they are good. If you have a late model 4X4 transmission it will not have the rear VSS (only the ISS) in the tranny as they are in the transfer cases now. You will have to get a reluctor installed in the tranny which sucks, but it has to be done to use the tranny.

3) Modify the rear tranny line. needs to be extended obout 6-8 inches. I cut mine off and used some compression fittings with a flexible line and re-connected the hard line to go into the tranny.

4) Cut the large ear off the passenger side top of the bell housing to accomodate headers. You also must replace the factory 5.3L flex plate with a flex plate and spacer from any 2002+ ¾ HD GM truck that originally came with a 4L80e transmission.


5) Purchase a Spicer yoke PN-2-3-14831x for the tranny side.

6) Cut and re-weld your driveline to coorespond to the tranny length. You can install the new yoke in the tranny, pull it out about 3/4in. measure center to center from the front ujoint to the rear ujoint. this will be the new drive line length. Be carefull about your driveline angle if it is lowered, or if you plan on lowering. Make sure the car or truck is on the ground with the rear end suspension under load to measure the drive line.

7) Get your STOCK HPT/BIN file segment swapped for the 4l80e. HPT support or ECTUNE can help with this. (THANKS ECTUNE !!!)

You will loose power but gain confidence from the swap. I recommend investing in a decent stall converter to get some back. The stock HD converted stalls at 2900 so it will have to be more than that. Get ready though.. they are expensive for the 80.
I am going to do a complete write up with picks here here on the forum shortley. In the mean time feel free to contact me with any questions.
__________________

 

[Sully]

ummmmm..... this might be the best thread I can find. He isnt doing it on an OBS, but its still a LOT of good info

http://www.performancetrucks.net/forums/showthread.php?t=424904&highlight=4L80E+swap

 

[Mike]

I have a thread on here with everything you need to know to do this.

 

[Sully]

yeah, it gave me the idea, but it doesnt cover that much. Silly 4 wheeling mags only giving you enough info to ask more questions. LOL

 

[hquick]

Hmm...I've done a couple of these swaps.
You need the input shaft from a np241 transfer case...as the 80E has a greater number of splines. Internally....apart from that input shaft...the manual NP241 transfer case and the push button NP243 transfer case are identical. So....just swap the input shaft and planetaries as a unit from the NP241 into the NP243.
The 80E is approx 1 3/4" longer than the 60E....so you need to have your rear drive shaft shortened by that much. You may get enough length out of the front shaft (I did).
The fluid lines need modifying.
There are some minor wiring changes to be made along with needing a tune from a truck equipped with the 80E. I use EFILive for my tuning.

Oh...and look for a 2000+ trans....they had all the factory upgrades by then. I guess something like a trans and transfer case from a 2000+ K2500 (with manual NP241 transfer case....not autotrac) should do it.

 

[4x4chevy]

Hell my 4l80e just blew up in my suburban,am going to do the monster trany 4l80e or swap to the 700r4.The 700r4 is hell of alot cheaper,but not as strong am not sure want am going to do yet.And by the way the 4l80e swap would be worth it, i beat the living hell out of mine and it had 209k on it tell that big ***** died lol.