Truth about 99 4l60e into 96

williscr3 · Jul 3, 2018

OK so what's the deal? Everyone's saying the 99 2 piece is a direct swap into a 96 but others say it fails shortly after. My 96 is starting to act funny. Slipping in 4th gear then it catches. I recently obtained a transmission From a 96 Tahoe, but the case says otherwise. It's a 2 piece 99. Will this work in my truck? Do I need a pigtail from newer truck so I can get the ground wire? Can I just use my connector and ground the case? I appreciate any input or real experience, thanks.

williscr3 · Aug 26, 2018

well in case anyone is wondering, my transmission started slipping even worse in 4th gear. i swapped in that 99 transmission. code on trans tag was 9LUD. fit right in, all plugs fit correctly. its shifting correctly and no slipping. all seems well. its been about a week now.

John P · Aug 29, 2018

No modifications? I guess you had to bend the Trans line to fit on an angle, was that all?

jdla140 · Aug 29, 2018

9LUD should be out of a 99 classic tahoe/burb or possibly silverado/sierra, should work great for you. I believe electrically all the PWM transmissions (96+) are the same, so you can swap 98+ into 96 or 7 without issue, but not the other way around. I swapped an 8TAD into a 99 NBS silverado and it worked great.

Vodka0tter · Aug 29, 2018

Whats the advantage of the later model swap, any?

williscr3 · Aug 31, 2018

no modifications at all. I did notice my transmission lines were incorrectly installed previously though. input on rad was lower one came out top then out to external factory cooler. i did however need new lines. i found that you can purchase the return line from external cooler to trans from (top port on trans), gmpartsdirect.com or amazon. part number is dorman 624-047 fits well and its nice having that one piece line again. as for advantage i dont believe there is one? its not the 4l65e so im not sure it has any upgraded parts like sunshell or anything.

Danyal Littleton · Jun 30, 2020

williscr3 said:
OK so what's the deal? Everyone's saying the 99 2 piece is a direct swap into a 96 but others say it fails shortly after. My 96 is starting to act funny. Slipping in 4th gear then it catches. I recently obtained a transmission From a 96 Tahoe, but the case says otherwise. It's a 2 piece 99. Will this work in my truck? Do I need a pigtail from newer truck so I can get the ground wire? Can I just use my connector and ground the case? I appreciate any input or real experience, thanks.

Hey did you have to use the flexplate dust cover from the 99v

Danyal Littleton · Jun 30, 2020

Danyal Littleton said:
Hey did you have to use the flexplate dust cover from the 99v

The front cover for the trans that goes at the rear of the motor my original trans isn’t a break away housing so it’s a two piece bell

Busted Knuckle · Jun 30, 2020

Vodka0tter said:
Whats the advantage of the later model swap, any?

For one thing, the lubrication system was changed to allow towing in OD. Prior to 1997, there was insuffient oil flow to the rear bearings to allow towing in OD. I've done it however on flat freeway, with no ill effects. Its the long hills that are bad.

The location of one of the trans lines should be different between these two versions.

At some point, could be with OBD2 in 1996, the TCC was modified to not fully lock up. Instead it has some "near" lockup with a PWM solenoid in control. This is how they are detecting misfires. If I owned one, I'd be looking for a way around that. Inside the valve body, there can be mods.

alpinecrick · Jun 30, 2020

Interesting....
My transmission rebuilder says the 96 internal harness is different than later years. He mentioned some builders don't know that, but the harnesses are different.

Truth about 99 4l60e into 96

williscr3

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williscr3

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John P

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jdla140

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Vodka0tter

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williscr3

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Danyal Littleton

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Danyal Littleton

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Busted Knuckle

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alpinecrick

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