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700R4 help please

700s only cool 30% or so when unlocked.. This is why they die so quick the lockup circuit allows more fluid to be pumped out into the cooler because it's not lost driving the converter, so if it can never lockup your going to kill it in short order. That temp is perfectly acceptable. Mine runs 150-160 or so in the winter and 200 max in 120 degree heat towing 7k.. Up big hills.. I don't ever tow in Od unless it's completely flat and I can go 65 or more.
 
Blue85 said:
The vacuum switch is normally located kind of underneath the brake booster and looks like this:
VacuumSwitch.jpg
Click to expand...

Blue85, thanks. I believe I've noticed this before, but I'm going to double check. My paperwork (from PO) shows the 700R4 was professionally installed and certified to meet warranty terms, so I'm assuming all those necessary parts were accounted for. I know the TV was set with a pressure test, which leads me to believe the installation was pretty thorough. Thanks for your help.

A last note, and I promise to stop hijacking this thread after this:
- doesn't it seem odd that with all the switches and sensors available, the lockup is not engineered to occur automatically when needed, and to disengage when not needed. What purpose would it serve to have a setup that allows the lockup to occur in lower gears, and which requires the driver to manually flip a switch on or off depending on his speed/driving conditions? I, admittedly, am not well schooled on the more intricate workings of a TH's torque convertor, and I'm sure there's a very good reason for it being setup the way it is, but it seems like it could be done in a way that wouldn't allow for driver ignorance/error...
 
A Corvette servo will increase clamping force on the second gear band, it is a cheap and worthwhile upgrade even on an otherwise stock trans.
 
well did all the fluids today and also found the TV cable broke
so i put a new cable installed the converter lock up kit but did not do the 2nd 4th vet servo yet
 
ok i drove my blazer today and got on the freeway
i dont like the shift from 2nd-3rd and 4th slips
i have played with the TV cable a few times and it does not change so i think its dying
the converter still locks with the lock up kit and the Corvette servo did nothing
so i think im gonna go with a Mad Dog trans thats rated for 500 HP
http://www.ebay.com/itm/LEVEL-2-700...m43e861ad04:m:mMmyPvesRe9rVS2slXTgBLQ&vxp=mtr
 
What kind of TQ is your motor putting out? If I've learned anything from Greg D., I'd be leary of a $1000 700r4 that'll support 500HP without stating how much torque it'll hold. I've gone the cheap route on a tranny once (Monster).
 
AJs72K5 said:
What kind of TQ is your motor putting out? If I've learned anything from Greg D., I'd be leary of a $1000 700r4 that'll support 500HP without stating how much torque it'll hold. I've gone the cheap route on a tranny once (Monster).
Click to expand...
around 350 TQ
 
Can you measure the line pressure? Or have a shop do it? Could still be a TV or pump problem that can be fixed with the trans in truck. Did you find a lot of clutch material (or metal) in the pan or old filter?
 
TV cable should be tight as a banjo string at wide open throttle, make sure yours is set as tight as it can be at that point. It is easy to cut a sealing ring on the 4th servo going back together, this will cause slipping in fourth gear.
 
Will a 700r4 from a 86 carb work in a 91 tbi. If so are any mods required
 
Greg Ducato said:
TV cable should be tight as a banjo string at wide open throttle, make sure yours is set as tight as it can be at that point. It is easy to cut a sealing ring on the 4th servo going back together, this will cause slipping in fourth gear.
Click to expand...
Thank you
My lap top died so im just seeing this
I will try the TV cable again
I put the stock servo back in
But it did all this before i changed servos after the old TV cable broke
 
Ryatt said:
Will a 700r4 from a 86 carb work in a 91 tbi. If so are any mods required
Click to expand...
You want an 87 or newer. The early 700's had an auxiliary valve body, and iirc there's a different spline count. (I use to know this stuff)

There are other factory improvements that make the newer (87 up) trannys more desirable. I'm on my second 86 'burb, you'd think I'd learn.
 
Ray, you are correct in that the 1987 and later units had better components internally, it is actually these later units that used the auxiliary valve body. All mid 1984 and later 700 used a 30 spline input, the 82 to mid 84 used a 27 spline and should be avoided for any kind of use other than weighing down a tarp or boat anchor.
 
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