"Rebuilt" 700r4 issues

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Obwonkonobe

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By the way. it is possible to check and see if the lockup is setup and working inside of the transmission without taking the pan off, wouldn't hurt to check. But this ^ really makes someone wonder what kind of builder this is. Most if not all rebuilds on any part should fully restore factory operation to the part being rebuilt. Also I for one would be pissed if a rebuilder did that without asking me first, In my mind why would I pay someone money to ruin a transmission just so they don't have to do their job fully.
Starting to think the same thing.. He's supposed to drop off my Speedo gears and pickup his core soon, I think Il have some questions for him
 

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I have had a ridiculous amount of trouble with my 700r4, a few of them actually. There is a really long thread on here somewhere about it. Whatever you do, I would not take it back to the builder you used. My problems finally got straightened out because I got it to someone who actually knew what they were doing. I had a few problems but the main ones were related to TV cable and improper lockup. If your builder did away with the wiring, maybe he set it up to lock up off pressure. I am no transmission expert, so maybe HotRod can say, but if it's set to lock up off pressure, and your TV cable isn't correct, then the pressure isn't correct, so lockup won't be right.

Now I am running a setup from Bowtie Overdrives for the TV cable. A B&M SuperCooler, and my lockup is set up the way it should have been. The trans is handling my almost 450 HP and 33 inch tires with no issues.

https://www.amazon.com/gp/product/B000CIGE9Q/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
 

Obwonkonobe

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@Splandman I've never heard of "lock up off" pressure. I know that in 4th the pump dosent supply much pressure, but I'm unfarmilliar with any modifications to change those characteristics. Can any one explain it a little more?
 

Splandman

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@Splandman I've never heard of "lock up off" pressure. I know that in 4th the pump dosent supply much pressure, but I'm unfarmilliar with any modifications to change those characteristics. Can any one explain it a little more?

I'm sure one of the other guys can. My builder set mine to lock up off pressure and it was not working correctly. I only found this out when I was under the truck and saw the electrical plug dangling. When I saw your comment that your builder got rid of the wiring, I wondered if he didn't also set yours up that way.
 

Obwonkonobe

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I'm sure one of the other guys can. My builder set mine to lock up off pressure and it was not working correctly. I only found this out when I was under the truck and saw the electrical plug dangling. When I saw your comment that your builder got rid of the wiring, I wondered if he didn't also set yours up that way.
Can you define "lock up off pressure"?
 

Splandman

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Can you define "lock up off pressure"?

As I said, I'm not an expert, but here is an explanation from another forum:

I am running the "hydraulic lockup" in one of my 700R4 and am happy with it. I also have a Ron Francis computer in another 700R4 and my Bud is running a Painless kit in his that I installed for him. While no expert, I think I have a fair grasp of the How, Why and Whens of the 700R4. The "hydraulic lockup" works off the pump pressure and is so simple and fool proof. The kit is a steel ball and a set of colored springs to choose from. I just happen to select the mid range spring and it seems to work fine for my set up. As you accelerate the motor, the pump pressure builds and overcomes the spring pressure, allowing the hydraulic fluid to redirect into the lockup valving to lock the converter. As you decelerate the motor, and wheel speed allows the pump pressure to decrease, the spring overcomes the reduced pressure and the torque converter unlocks. I have never experienced any failure to unlock and I have experienced lock up in other gears, under heavy acceleration, but you would never notice this if you were not really looking for it to do so. It is not a malfunction and no unusual wear and tear will occur.



Unlike the guy that wrote this answer, I experienced all kinds of trouble. Mine was locking up way too early, it locked up in all gears but 1st, and also was coming in and out of lockup constantly while in 4th. At one point I thought I had a bad converter. A lot of my issue may have been the improper TV cable bracket, it's hard for me to say because I got the new bracket and changed the way may converter locked up at the same time. I only know it works great now.​
 

Obwonkonobe

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@Splandman great explanation thank you! So its basically a mechanical lock up, I like the sound of it
 

84 M1008

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I'd give it a test drive as is. My cable would not adjust by itself and I had to do it by shift feel and rpm. Took several short drives till I got it right. And honestly if not using the converter lockup why get a 700r4? Just seems a bit counter productive to me, someone else will chime in. But I personally would hook it up. Mine also drops the rpm about 400+ while cruising.
Guys like me that have a 6.2 and 4.56 gears appreciate that 400rpm drop.
 

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^this is what I was thinking as well. Just wouldn't be able to put it to words. And honestly a transmission builder saying something like that would make me question somethings.

Also on a side note a trans that is constantly locked will be super under-powered feeling and slow until you get it in higher RPM but even then it will never unlock which will be very bad.
That would be the point of having the TC lock up vacuum switch in place, when vacuum drops as you step deeper into the gas pedal, vacuum pulls the switch open, unlocking the torque convertor
 

84 M1008

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I got it to work by loosening the tv cable. But now at WOT there's still a little bit more that i can pull out on the cable. Do I need to be worried about this? My shifts seem to be stacked a little bit too now that its loosened. How sensitive are these cables to adjustment?
The cable slack at idle should be no more than a 1/32 of an inch. It should not be guitar string tight.
 

84 M1008

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Ideally, there should be zero slack in the TV cable when the throttle is fully closed. (Wedge the choke plate open so fast idle speed isn't set). And at WOT, the cable should be pulled out as far as it will go.

On the very first one I ever adjusted, it appeared the cable was pulled all the way out at WOT. However, there was slack in the cable at closed throttle which made me drop the pan and do some detective work. Turns out the cable rod (on the trans end) was getting hung up in the cable housing, keeping the lever from moving the valve all the way in.

But anyway, it's not magic, nor does a pro have to do it.
There is a throttle valve upgrade that prevents sticking. If the rebuilder didn't install it, along with a corvette govenour, they don't know very much about a 700R4,
 

Obwonkonobe

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There is a throttle valve upgrade that prevents sticking. If the rebuilder didn't install it, along with a corvette govenour, they don't know very much about a 700R4,
Unfortunately I had to put in the corvette servo, and am yet to put in a shift kit or anything else
 

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