4l60e with a 5.3

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05-20-2012, 07:52 PM
matt1994

4l60e with a 5.3

Hi, im planning on swapping a 5.3L into my 94 Chevy 1500 that originally came with a 4.3L. I already have a complete wiring harness and some other parts from a 99 Chevy truck that had a 5.3.

i found this website that shows what wires i need to make the engine run on its own. i was wondering if anybody knew if this will work good.
http://lt1swap.com/99-02_vortec_pcm.htm

But my real question is i want to keep the 4l60e that i have in the truck now that was originally behind the 4.3L. since it was replaced not to long before the 4.3 went out. and i was wondering how i could make this work. i know the transmissions changed after 94 and i might need the flexplate spacer im mostly worried about the wiring can i hook it up to the harness i bought? If not can i modify it to make it work or do i have to buy different transmission? I don't have enough money to buy a stand alone computer and that wouldn't make sense since they are sooo expensive i could buy a 99 4l60e for the same price. Any help would be greatly appreciated. thanks.
05-20-2012, 08:20 PM
94_OBS

Trans will not work with your new harness as it sits. in 1994 some 4L60E's had PWM "Pulse Width Modulators" and some didn't. Only way to find out is to look inside the case, it will be stamped PWM. Anyway, the new harness will not work. You can try to talk to Nelson Performance about modding your harness. This is one of the reasons I have gone Carb'd with my 1994 silverado.
05-20-2012, 08:24 PM
94_OBS

Here is a quote from another member on this forum about this same question

Quote:

Originally Posted by Z-Rod

Hi L&M,

Be very careful with the advice you receive about your '94 4L60E transmission and ECM controls. All late model computers expect to see a PWM TC. The difference between a PWM TC and non-PWM TC is about $2,000 in an unneccessay tranny repair. Running the wrong TC will ruin the TC "clutch plates" in a few months. There are too many examples of failed tranny because of this.

Here is what I did on my 1994 Z-71 with the stock non-PWM tranny. Nelson tuned my 2005 computer so it did not pulse the TC clutch. He also had to re-pin the tranny plug to match my tranny. Code P2761 was deleted among other things needed to make the computer control the non- PWM TC. The proper operation of my TCC was confirmed with a GM Tech II scanner. My TCC locked and unlocked as it should with 0% slippage. You need to hook up the wire from the brake pedal that lets the ECM know when the brake is applied. I would, however, make sure your tranny is modified to handle the extra HP... the factory 350 was rated at 200hp.

there was a period of ECMs that could not be modified like the 2005 ECMs... so you will find some people say that you can't use these trannys. If you are using a ECM like mine... you are in luck providing it is programmed correctly.

This is a blatant plug for Nelson Performance... The guys there know their stuff. They are experienced with these swaps and understand the inside of those little magic little boxes.

Z-Rod

Here is the complete link:
http://www.ls1truck.com/forums/lsx-t...lder-4l60.html
05-21-2012, 03:48 PM
matt1994

So i cant replace the internal wiring harness without ruining my relatively new transmission? So i have a couple options i could do a carb setup with the trans i have now? Or I could go out and buy a newer transmission that was made to bolt up to that 5.3 and plug in no problem. i think thats about it or am i missing another way?

what do you guys think the best option to go to keep the efi im not 100% against a carb but id much rather have the efi as long as its not a lot more expensive. I REALLY dont want to go back to the old 4.3 or a 5.7.

94_OBS what are you planning to to do for a transmission keep the 4l60e with the carb?
05-22-2012, 08:42 AM
94_OBS

Quote:

Originally Posted by matt1994

So i cant replace the internal wiring harness without ruining my relatively new transmission? So i have a couple options i could do a carb setup with the trans i have now? Or I could go out and buy a newer transmission that was made to bolt up to that 5.3 and plug in no problem. i think thats about it or am i missing another way?

what do you guys think the best option to go to keep the efi im not 100% against a carb but id much rather have the efi as long as its not a lot more expensive. I REALLY dont want to go back to the old 4.3 or a 5.7.

94_OBS what are you planning to to do for a transmission keep the 4l60e with the carb?

I am keeping my existing 4L60E and attaching the TPS sensor from my TBI onto my carb. I just need it to last about a year till I get a T-56 to swap in. My opinion is to call Nelson Performance they will give you the best answer. I personally would get a newer 4L60E. The one you have now is only rated at around 250hp and will not last. I am only using mine until I get the T-56 otherwise I would have gotten a newer 4L60E.
05-22-2012, 06:36 PM
matt1994

yeah thats what i thought you would be doing. I know it is rated a little low but yeah it would be temporary. you said that your using a tps. So do you think i could modify my engine wiring harnesse like in the diagram in the link i posted so it will just run like it would if i was using a earlier model transmission and use the old transmission with a tps that way i could still use the efi? i dont have enough money now for a engine AND a new transmission.