Can I swap my 4l60e for a Th350/400?

[TheDirt520]

I have a 99 suburban 1/2ton 350/4l60e ,, when my 4l60e goes out can I swap it for a th350/400? I know it's possible just tryin to figure out what I'd have to change? I'm building a crawler so strength is key, a 4l60e and np 241 aren't strong , I have a rebuilt th350 and np205 layin around I'd like to use,, any help would be great
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[andrewmp6]

If its one of the ls engines you'd need a adapter kit to use a older style trans on it.

[TheDirt520]

I don't think it is , just a 350 like ud find in any 96-98 chevy
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[TheDirt520]

I'm more worried about the computer not workin right or and other problems that may occur losin the computer controller trans
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[luvbowties]

Originally Posted by TheDirt520

I'm more worried about the computer not workin right or and other problems that may occur losin the computer controller trans
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Hey, 520. I'm 99.9% sure you'll need to have your computer reprogrammed($75-$150). Maybe check with one of the online fuel-injection-conversion-harness companies to verify. Or even with a performance overdrive trans rebuilder like PATC.
Good luck with your decision!
sam

[TheDirt520]

Will do thanks,, I just know when that damn 4l60e decides to take a dump on me I can put a rebuilt th400 and buy and rebuild a np205 for what the 60e will cost,,, I don't really care about losing the overdrive, other then a trip to Moab it won't see much freeway use
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[blazerboy_4life]

I am curious about this as well. I have a 97 Silverado Extended Cab Short Bed4x4 I didnt pay anything for and I dont want to spend $2,400 having the 4L60E rebuilt. Its got a Vortech 305 and 4x4 shifter on the floor. Aside from driveline length would I need to worry about adapters for the xfer case or mounting up to the motor? I only plan to use the truck as a work truck to pull my bobcat trailer or haul a car around on.

[BigBlocksRule]

Might be able to find a computer and harness from a truck with a stick tranny so it has no input needed from the transmission.

[blazerboy_4life]

I didnt think about that
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[luvbowties]

Originally Posted by TheDirt520

I have a 99 suburban 1/2ton 350/4l60e ,, when my 4l60e goes out can I swap it for a th350/400? I know it's possible just tryin to figure out what I'd have to change? I'm building a crawler so strength is key, a 4l60e and np 241 aren't strong , I have a rebuilt th350 and np205 layin around I'd like to use,, any help would be great
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You said, "I'm building a crawler...". You do realize you would not only be giving up od, but also the extra low 1st gear which I assume you would want for crawling?

[tattoed71]

i put a turbo 350 trans in my 91 with a vortec block. had to move cross member up few inches didnt haft to modify driveshaft went right in.besides the lose of overdrive my speedo dont work but my trusty tom tom does the trick but no pcm tuning im running the vortec setup. but im not 4wd but hopefully this gets u closer to ur goal.
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[luvbowties]

You said the following, "paint dont make u go faster". I agree. I'd like to add..."but it may cause a person to enjoy driving his truck less".
sam

[tattoed71]

its for the guys that spend all there time and money and look at it get out and enjoy what u build
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[tattoed71]

and for the guys that put racing stripes on their rides and think they got something special.
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[ala1941]

Anybody use a Transgo 46-MOD vacuum modulator to control one of these electronis transmissions ?

[400sbctruck]

At worst youll get a code. Earlier th400-kickdown cable later some electronic(by this time it was th375b/standard in trucks). Go with 375/400 and probably flash shift duties out of ecu/pcm. Vacuum shifted them all and kickdown was main diff.
Really savvy programming guy may put different settIng in your pcm to allow use of 1988-1992 th375b trans later of which was electric kickdown.

If this is for power handling i would take 375b although 700r4 can do good with few upgrades such as the covette servos etc. Main performance difference would be 1-2 gearing difference, as 375/400 is steeper off the line.