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68 TT · 08-08-2009, 09:18 AM

I am assuming you meant 4L80E conversion as you stated both 4L60E and 4L80E and the 4L60E is a waste of time in a truck as the are just not very strong. There is a reason GM put the 4L80E in the 3/4-ton & up trucks and only used the 4L60E in 1/2-tons & light duty SUV's.

I put a 4L80E in my 68 Camaro drag car and love it. The functionality and amazing amount of control you have over transmission functions is incredible with the electronic trans. You can change shift firmness and shift points for each gear change in just a few minutes with your laptop and a chip burner without even getting your hands dirty.

I also put the LQ4 6.0 liter and 4L80E out of a friends wrecked 2500HD into my 2003 Tahoe in place of the 5.3 & 4L60E when the stock 4L60E tranny failed for the second time. The first time was under warranty this last time it was not so I did the conversion. Great very tough tranny.

2wd conversion to 4L80E no problem. Install the PCM and wiring out of the transmission donor vehicle. You can tune the chip to make it function as a trans only controller if you are running a carb or use it to control the whole engine including TBI if the donor vehicle is a 91 to 95 vintage using some free software and an inexpensive chip burner. 96-up vintage will require some expensive tuning software as the computer changed to OBD-II and if you want engine control the OBD-II system requires a crank position sensor that the older engines just don't have. You can get the parts to convert an older engine but I don't think it is worth the cost. The guys at thirdgen.org have worked out the OBD-II 411 PCM swap for the TPI cars and list all the parts needed to use the newer PCM.

4x4 conversion is a little harder / more expensive. The biggest problem is that the transfer case that they are mated to is drivers side drop except in one very rare vehicle. To hook up our NP205 or NP203 transfer case requires a special adapter except if you can find the very rare 91 quad cab dually and even in that the 4L80E was just an option so not all of those had it. Many were T-400 trucks.

An option for the NP205 to 4L80E is at NP205.org where Paul has figured out how to connect a more common 2wd 4L80E to an NP205. The biggest problem here is that the assembly is longer than any stock square body drivetrain combo so you will have to build a custom front driveshaft and have the rear driveshaft shortened plus relocate your crossmembers. I plan on doing this with my SM465/NP205 truck and am in the process of accumulating all the parts for the conversion.

Hope this helps.

08-08-2009, 09:18 AM	#2
68 TT Still plays with trucks Join Date: Jul 2009 Location: Spokane, WA Posts: 3,570	Re: Anyone Try a 460LE I am assuming you meant 4L80E conversion as you stated both 4L60E and 4L80E and the 4L60E is a waste of time in a truck as the are just not very strong. There is a reason GM put the 4L80E in the 3/4-ton & up trucks and only used the 4L60E in 1/2-tons & light duty SUV's. I put a 4L80E in my 68 Camaro drag car and love it. The functionality and amazing amount of control you have over transmission functions is incredible with the electronic trans. You can change shift firmness and shift points for each gear change in just a few minutes with your laptop and a chip burner without even getting your hands dirty. I also put the LQ4 6.0 liter and 4L80E out of a friends wrecked 2500HD into my 2003 Tahoe in place of the 5.3 & 4L60E when the stock 4L60E tranny failed for the second time. The first time was under warranty this last time it was not so I did the conversion. Great very tough tranny. 2wd conversion to 4L80E no problem. Install the PCM and wiring out of the transmission donor vehicle. You can tune the chip to make it function as a trans only controller if you are running a carb or use it to control the whole engine including TBI if the donor vehicle is a 91 to 95 vintage using some free software and an inexpensive chip burner. 96-up vintage will require some expensive tuning software as the computer changed to OBD-II and if you want engine control the OBD-II system requires a crank position sensor that the older engines just don't have. You can get the parts to convert an older engine but I don't think it is worth the cost. The guys at thirdgen.org have worked out the OBD-II 411 PCM swap for the TPI cars and list all the parts needed to use the newer PCM. 4x4 conversion is a little harder / more expensive. The biggest problem is that the transfer case that they are mated to is drivers side drop except in one very rare vehicle. To hook up our NP205 or NP203 transfer case requires a special adapter except if you can find the very rare 91 quad cab dually and even in that the 4L80E was just an option so not all of those had it. Many were T-400 trucks. An option for the NP205 to 4L80E is at NP205.org where Paul has figured out how to connect a more common 2wd 4L80E to an NP205. The biggest problem here is that the assembly is longer than any stock square body drivetrain combo so you will have to build a custom front driveshaft and have the rear driveshaft shortened plus relocate your crossmembers. I plan on doing this with my SM465/NP205 truck and am in the process of accumulating all the parts for the conversion. Hope this helps.