700r4 Transmission Help

[Orlando87Chevy]

I have been debating very heavily about what transmission I should throw in my 87 R10. Between my wheels, rear end gearing and the 350 I'm having built, I'm trying to have fun but still have a nice cruiser. So I've pretty decided to go with a 700r4 tranny because of the overdrive and build it up with a Bowler Lock Up kit. Now the only thing I'm unsure about is 1. Is the transmission computer controlled, and 2. Is there away to isolate the computer controls from the rest of the wiring. Heres my dilemma. I plan on rewiring the whole vehicle so I'm trying to plan ahead so when I'm ready i will have a firm grasp on what I need to do. I hope all this makes sense.

[Fairlane514]

It is not computer controlled.   It has a throttle valve cable they controls shifting and the pressure. This connects to your carburetor to TBI or fuel injection.

[Mike Phillips]

I put a 700r4 in my 1975 Jimmy and it was out of a 1985 or 1986 Blazer.  It only has the one-wire setup to lock up the overdrive and was simple to install.

I was told sometime during or after 1986 the 700r4's started using the computer controls.

One thing for sure, for a 4x4 with large tires, I would never do the 700r4 again, it works great but I mostly drive around town so I hardly ever use the overdrive. 

[DnStClr]

What Fairlane514 said-The 700R4s aren't computer controlled. The wiring going into the trans doesn't activate solenoids and actuators for shifting like the 4L60E does, and the 4L60E didn't come out until the mid 90s I think.
The torque converter lock-up in the 700R4s is activated by 12volts dc, and this is what confuses people to think it's electronically shifted.
I think the 700R4 can handle @500lb/ft of torque when properly rebuilt. But higher torque requires an upgrade to a 4L60 or 4L80 E trans.

[jaredts]

What they said.  Keep in mind that you will have to make the 12v signal somehow to lock up the torque converter.  You can replicate the factory setup fairly easily, buy an aftermarket controller, use a toggle switch......  Web searches will give you more info. than you can read in a day.

[Orlando87Chevy]

Thanks for all the help guys. I saw Bowler Transmissions makes a bracket kit for Throttle Shift which also includes the Lock up module. Wiring the transmission should be a piece of cake now. Now if only I didn't sell my old 700r4 transmission for $75. Looks like I will have to buy a rebuilt one now.

[Fairlane514]

You might consider finding a core (87 and up) somewhere, buy the rebuild kit from Monster transmission and come out cheaper.

[Orlando87Chevy]

You might consider finding a core (87 and up) somewhere, buy the rebuild kit from Monster transmission and come out cheaper.

Is there any reason why I should go with an 87 and up tranny? Most likely I will end up rebuilding a core if I can find one cheap.

[Fairlane514]

The early ones (before 87) had some inherent weaknesses that were improved by 1987. I believe they got better even after that, but 87 would be the earliest year to look for.

[Orlando87Chevy]

Crap!!! I hate to sell my transmission! I had a 700r4 out of my 87. I was told they were useless so I got rid of it. I'm going to ask the forum first next time.

[Captkaos]

1987-up had all the updates including the better pump and they can accept all the upgrades up to 1993 (when it went to electronic shift) and it will also accept some 4L60E hard parts.

[Orlando87Chevy]

How do you know what year the transmission is? Is there a number i can reference on the transmission?

[Fairlane514]

There is a stamped number on the passenger side just above the pan.  Mine is a 1984 and I seem to remember the second digit being a 4 which means 1984.

If you google it you can get an exact location for the number.

[454Man]

hope this helps

[Orlando87Chevy]

That's great. That helps a lot. Thanks