Conversions & Hybrids - Question about wiring up 700r4
07-10-2010, 06:41 PM
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.
07-10-2010, 06:50 PM
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.
07-11-2010, 09:19 AM
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.
07-11-2010, 10:59 AM
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.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=TC&Product_Code=376600&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/sumner/techinfo/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.
07-11-2010, 03:55 PM
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.
07-11-2010, 09:29 PM
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.
07-12-2010, 02:58 PM
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.
07-12-2010, 03:08 PM
If you use the B&M lockup kit, you don't have to go through the brake switch as it is speed operated and will automatically unlock the convertor at whatever speed you have it set for.
11-21-2010, 07:44 AM
Do you think the wiring could be spliced into to send the vss signal to the ecm? It looks just like the stand alone unit that dakota digital sells.
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