Wiring harness question

[__CHI__]

Do i have to change the harness in my 91 4.3 truck to drop in my 350tbi/4L60e from my 95 tahoe? Ripping the 4.3 out tomorrow and hoping to get the 5.7 out as well so we can have it done by saturday

 

[Nathaniel2g]

I'm not entirely sure what the differences are in sensor, but on the transmission side I'm pretty sure your 91 would have a 4L60, not a 4L60E, so you're going to need that part of the harness at least. If you're pulling them anyways, I'd probably swap them all over.

You may run into tach issues, as I believe they use a different tach sensor or something like that between 91 and 95. Your 95 is the new style interior too, which means the cluster is different so I'm not sure what all is involved there, I'm guessing different plugs/harness.

 

[__CHI__]

The 91 has a turbo 350 in it,originally a 5spd. Tach doesnt matter all that much as long as it runs and atleast moves lol I'll be sure to keep up with this post though incase anyone else had similar questions

 

[Nathaniel2g]

Your speedo won't work at all if you can't get the information from the transmission to the ECM, and from the ECM to your cluster.

 

[Steve A]

Where the '91 was converted to auto with a TH350, you'll need to move the PCM and wiring harness with the motor & tranny swap so that they will run and shift. There's a good chance the '95 speedo was electronic so inside the transmission is a reluctor and not a gear to drive a speedo cable. There is Technical Bulletin for the '95 4L60E, file attached for any concerned. BTW, the '96 manual valve the TB refers to is available from RockAuto for ~$10-11.