92 C1500 automatic to manual.

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Chris craig

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I have a 92 C1500 with a 350 tbi and a 4L60. NOT A 4L60E. I’m wanting to swap to a T56. I’ve seen the write up of 4L60E to a t56 and I couldn’t find anything helpful about the computer. Computer wise is there anything I need to change? Is there anything in the ECM that would hinder the swap? I’ve gotten the mechanics pretty much figured out. I’ve searched around on google, YouTube and on here and I can’t find anything. I’m trying to get this done in a weekend so I don’t want any surprises. Thanks in advance.
 

Schurkey

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C1500 will have the vehicle speed sensor in the tailhousing of the transmission. Make sure the new trans is compatible.

The computer expects to control a torque converter clutch. It'll be unhappy if that's disconnected. No doubt it can be tuned-out.
 

Chris craig

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C1500 will have the vehicle speed sensor in the tailhousing of the transmission. Make sure the new trans is compatible.

The computer expects to control a torque converter clutch. It'll be unhappy if that's disconnected. No doubt it can be tuned-out.
How do I do that? I’ve looked on google about tuning to change that but the only thing I find is tuning to add power?
 

Chris craig

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No idea. I don't do computer tuning.

Don't forget that you'll likely need a different driveshaft, depending on the length of the "new" transmission compared to the "old" transmission, and the output shafts may have different diameters, too.
Oh yeah I’ve already got all that figured out. I’m just not very electronic savvy.
 

A97obs

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Oh yeah I’ve already got all that figured out. I’m just not very electronic savvy.
Just my 2 cents …I’m onto a similar swap but only my route is nv3500 and on a 98’

What I do know is You’ll need the 88-95 style clutch pedal -not a 96-98
And you’ll need to run the NSS into the cab and wire it to the Clutch pedal assembly switch so it acts like a factory push clutch to start.

I believe you can also choose to ground that NSS “Neutral safety switch “wire and you won’t need the clutch presses to start but it’s not really wise or proper way .

There will be a high idle and sel light if you don’t tune the pcm for a manual trans swap …another guy said black bear performance is the best place to send it off to
 

Ace17

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Yeah as others have mentioned, there are differences in the PROMs for the manual and auto trucks. I have the EBL tuning system, so I did my own custom tune. What I'd advise you to do is just go to the junkyard, and pull a computer from 92 c1500 or similar year(88-94 will do, but I'd hunt hard for a 92). Or, you can go on Ebay and buy one there. People are selling ECMs on there all the time, and you can probably find one for your specific year.
 
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