Hoping for some advice. I just completed a rebuild of my 700r4. This is my 2nd 700 rebuild. Not sure why it shifts all the way into fourth gear as low as 25 mph at lite throttle pressure.. Also, when slowing down it doesn't downshift into 3rd; it stays in 4th all the way down to 25. It has the same corvette governor my other trans has which works correctly. Everything else works great. It will downshift into 3rd if I manually do it. At WOT it shifts 1-2 at 4500 and 2-3 at 5000. I checked and re-checked the TV cable. All is good there. Not sure what else could be causing this.

 

From the FSM the only symptoms that apply are "no part throttle or delayed downshifts".

Check the following:

External Linkage: Adjustment

2-4 Servo Assembly: Apply pin seal cut/damaged; servo cover retaining ring omitted or misassembled; 4th apply piston damaged or misassembled; servo inner housing damaged or misassembled.

Governor Assembly: Weights binding; Governor valve stuck.

Valve Body Assembly: Throttle valve, 3-2 control TV modulator valve(s) stuck; TV sleeved turned in bore; 4-3 sequence valve body channel blocked; missing #5 check ball.

At least the trans doesn't have to come out to check these things.

 

Thanks for the quick reply. I am thinking its in the valve body. I put in new billet 2nd and 4th gear servos and a new corvette governor. I didn't do anything to the valve body, just cleaned with some cleaner and checked the valves by moving them in the bore. Didnt remove each and clean as I did on my first 700. I am thinking something in there must be sticking. I think I am going to get a constant pressure valve body and put in there. Maybe that will take care of it.

 

DO NOT get a constant pressure valve body, they will have way to much pressure at low throttle openings and the shifts are too firm. And at WOT the shifts are not very firm. They wear out the front pump in short order and are very hard on sealing rings and other parts. What year is this transmission do you have here?

 

I wasn't aware of those issues. Thanks for the advice.

The trans is a 92. I have another valve body from another 92 that had a Transgo kit in it from when that trans was built at a local shop. The TV valve assy was revised as well as some different springs. I disassembled it last night and cleaned everything. I was thinking I would try it in the car as well as replacing the TV cable. I have a new cable coming in the mail. As a side note I also used a Transgo 700P plate during the rebuild.

 

Well still no luck. I replaced the tv valve in the valve body and confirmed the plunger bottoms out just as I hit WOT. Today I tried switching in some different governors I had. I tried the original governor, the corvette governor, and a third governor that was in my old trans that had lighter springs and weights. Will still shift into 4th and lock the torque converter at under 30mph. Could it be something else in the trans other than the valve body, governor, or TV cable?

 

what happens if you tighten the TV cable a few clicks??

 

Any update on your cause of OD shifting early? I have similar issue with 406 with 700R4 with corvette servo and stage 3 shift kit in car I bought a year ago. I wasn't sure if that was the normal operation of the way they setup the trans or if there was a problem.

 

My main issue was that it was setup to lock the torque converter when it shifts into 4th using a switch on the valve body. It really became an issue with the torque converter locked in 4th at 25 or 30 MPH. It really didn't like that. I had a B & M controller sitting around that connnects to the speedometer cable and gives me the ability to control what MPH it locks up at. I set it to not lock unless it is over 42MPH and in 4th. That seems to have taken care of my issue. The shift points still are not like my other 700r4, but at least it drives well. If I was still conserned about it I would try installing a rebuild valve body. So far as I have been able to determine that is the only other thing that could cause it.

 

has anyone figured out the problem causing this issue? i am having the same issue with my 1989 700r4 i have already set and triple checked TV cable with the pan off. It has good firm shifts 1-2-3 but unless 1/2 throttle it will be in OD at 25-30 mph unless half throttle or above then it will shift into 4th at 40. trans was rebuilt and only has 1000 miles on it. also will remain in 4th and not downshift until 25mph. Was having the same issue with the converter locking at 25-30 but i remedy a tow/haul button i can turn off lockup manually and then turn it on when above 50mph. i would like to get it figured out i don't want to have to drive it so hard 1/2 throttle take offs for it to shift out.

 

change the governor with z28 or corvette part or get a governor reprogram kit installed, that also controls WHEN it shifts