Question about wiring up 700r4

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Jul 10, 2010 | 06:41 PM

classic79

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Question about wiring up 700r4

I have an 89 suburban going to drop in a 4.8 out of 02 tahoe, got the harness and computer from tahoe. Going to reuse my 700r4 transmission.

How do I hook up the TCC for the transmission? Will the new pcm from the tahoe control the lockup now? Or do I have to buy a standalone kit for the transmission.

Thanks for the help, first time doing this swap so probably have some more questions.

Jul 10, 2010 | 06:50 PM

-Joseph-

LSxGuy widda 9sec Mustang

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From: Texas and Qatar

GM sells a lockup kit with a vacuum switch that was inexpensive. It is in the GM Performance Parts catalog.

The harder install is the throttle valve cable, you will probably need to weld or modify a TV cable mounting bracket to the 4.8L throttle bracket (or grind it to fit) and add a bracket to the throttle arm. Or you could grind the cruise control bracket off the throttle body and reweld it rotated 180 degrees for the TV cable.

Jul 11, 2010 | 09:19 AM

classic79

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you have a part number of the gm part. haven't found it yet.

for the TV cable I was going to use the TVmadeeasy kit from bow tie overdrives.

Jul 11, 2010 | 10:59 AM

-Joseph-

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I don't see it either, I know they had one at some point as I bought one. It was about $50 and similar to what mid-80's cars/trucks were equipped with since they were carburetor engines with 700R4 and lockup. The only other "kit" is from TCI, http://www.compperformancegroupstore...Category_Code=

Here is some other info, some if it looks like it was drawn on a napkin and scanned, but the info is there. http://purplesagetradingpost.com/sum...o/700R4p1.html

Looks like some guys are using the 4th gear pressure switch to do the lockup functions, I've done this on a 200-4R. The only problem with that is the clutch will not disengage until you downshift, but would be fine for steady speed cruising. You could wire in a vacuum switch to interrupt the lock-up power wire so you wouldn't have to downshift to get out of lock-up mode to accelerate in 4th gear.

Jul 11, 2010 | 03:55 PM

classic79

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Thanks for the information. I think I might have finally found the gm kit. its like 45 bucks it says for installing 700/200 in non computer vehicles.

Jul 11, 2010 | 09:29 PM

LS1MCSS

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Go to Summit and get the B&M kit. It's a little more expensive than the others but well worth it. It's speed controlled and adjustable.

Jul 12, 2010 | 02:58 PM

classic79

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An additional ? on pin 33 blue connector is TCC brake switch. Would I leave this off or tap into the TCC brake switch on my 89 suburban brake pedal switch? What does this let the computer do if anything if I am running a 700r4 and not a electronic transmission.

Also mind was wondering and thought that I might be able to leave my 89 ecm and wiring in place and would the transmission work then with respect to lockup? Or did the 89 tbi setup use a engine input in determining lock up.