For those running the older 4L60 trans on their LS swap

[droopyzda1]

Hey guys I wanted to get some feedback on those of you that have an older 4L60 trans on you LS swap. I am going to use my 1994 4L60 without PWM on my 5.3. I already have the LS dished flexplate bolted up to the engine with the spacer at the end of it with the elongated flexplate bolts and have opened up the flexplate bolt holes to line up with the 4L60 torque converter. I just wanted to know how you guys personally had the LS PCM work with the older 4L60 ? Any simply mods done to make the trans withstand the power, like a shift kit, different torque converter ? I was simply going to change the internal trans harness to that of a 13 pin and add the PWM solenoid to the valve body. I read about this on a previous thread and was thinking it would be easiest way to go on my application. Also I would like feedback from you guys on how that 4L60 has been holding up, I do NOT plan to race or abuse it, just the occasionally "push" when I need it. If I were to run a 4L80 in the future, I would not have to have the PCM reflashed again, is this correct? That is another reason I was going to change the internal trans harness. Thanks and this site has been awesome so far for the swap !!!

[kewljay223]

im not sure but i dont think the new pcm can control it since its not pwm... so i cant really help you there. but i do know that if u want to run the 80, the pcm will have to be programed for it. since its a 5.3, im pretty sure it didnt come in an HD truck which comes with the 80's so im almost positve your pcm is setup for a 60e or 65e which will not controll the 80e. also you will need to repin a few wires on the round connector for the 80. i just bought an 80e about an hour ago.. lol so im about to dive into that swap. ill know more about it after i go through with it so i cant help too much more. hope i helped a little though.

[Mickeymotormount]

So far, my 4L60E from a 99 Escalade has been holding up well behind my '99 6 Liter. I don't abuse it either. Occasional 3500-4000 lb. loads of scrap to the scrap yard and still holding fine. I have 6500+ miles since the swap and don't really know how many miles on the trans since the Escalade donor had the dash ripped out of it.

As for the PCM flash, I would have to think your 5.3 PCM should be able to run the older 4L60E provided you change your internal harness. Not sure but it sounds reasonable. My PCM was reflashed to remove VATS and to program it to run the 4L60E since the 6 liter originally had the 4L80E behind it. Was also programmed for tire size, gear ratio, tachometer, etc.. To date, no issues. Knock on wood.....LOL.

[droopyzda1]

Hey guys. Got her running finally and drove it around the block. But the trans does not shift out of 1st gear. I can manually put it on "2" and its on 2nd gear. I checked the trans fluid and its at a normal level even with the larger trans oil pan. I changed the internal harness to the one with the extra pin on it. And also installed the pwm solenoid to the opening on the valve body where it should go and installed a new oem filter. The pcm was reflashed but I did not tell him to touch anything that has to do with the trans. I connected the old vss by soldering it and heat shrinking. And hooked up the tcc switch. Am I missing something?

[kewljay223]

What was behind the 5.3 before? was it a 60e? if not and you didnt get the trans portions flashed into the pcm... then maybe you need to? make sure you didnt reverse wires for vss.... im not sure. need more info

[droopyzda1]

Your guess is as good as mine on what was behind the 5.3 ! This is a Frankenstein swap ! I have pieced everything together from Craigslist and ebay. I thought I did all the research and could use my pre `95 4L60 on the 5.3. I would just have to change the internal harness to that of a `96 and later. All the trans controls are from factory on the pcm I would assume. I just told Brendan from lt1swap.com to remove vats and give me some better fuel mileage. Will check the wires on the vss but I soldered them to each corresponding wire and from the harness by color.