Author Topic: puttin' the 700r4 back in my 87  (Read 2584 times)

Offline robzkool2

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puttin' the 700r4 back in my 87
« on: July 28, 2008, 11:33:47 pm »
my 87 1/2ton 2wd originally came with a 305tbi & 700r4 trans combo.when i bought the truck it has a 305 carb/th350 combo from i'm told an 84 suburban.the carb iz a 600 holley.my th350 broke and i'm puttin' a 700r4 with torque converter back in.the salvage yard said it came from an 84 suburban.the speedo looks to have a wire connector instead of a cable on the tailshaft.and it has the white 4-pin connector on the left for -i guess- the lock-up.the 87 computer iz still in the truck but not hooked to the engine.should i just ignore the computer and set up the trans as a retrofit install or can i use my existing wires?can i use the th350 dipstik & tube on the 700r4?how much length will have to come off the driveshaft?it's already been shortened an inch & half for my axle-flip drop.

 
keep 'em shiny side up!

87 GMC Sierra half ton driver
79 Chevy El Camino project

Offline Leevon

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Re: puttin' the 700r4 back in my 87
« Reply #1 on: July 29, 2008, 10:18:25 pm »
your ECM would have originally controlled the 700R4 lock-up (TCC).  Since you're not using the computer harness, stand alone will be best for the trans.  As long as your trans has the internal provisions, you basically just need to run switched 12v power through a vacuum switch and brake cancel switch (junkyard, free or cheap) to the trans. 
1950 3100
1971 Cheyenne
1987 Silverado
2018 Silverado

Offline Captkaos

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Re: puttin' the 700r4 back in my 87
« Reply #2 on: July 29, 2008, 11:42:17 pm »
Look here to make it lockup:  http://www.73-87.com/7387garage/drivetrain/lockup.htm

You will probably need to shorten it about 1.5", but you need it in there to measure first.