How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Pragueress Your Own Question
Pragueress, Instructor
Category: Classic Car
Satisfied Customers: 744
Experience:  Automotive Instructor 25 years; ASE technician; author of 3 automotive books
Type Your Classic Car Question Here...
Pragueress is online now
A new question is answered every 9 seconds

700R4 Transmission problem

Resolved Question:


I recently aquired and old school hot rod 50 Ford Coupe sitting on a 65 El Camino frame, 350, with 700R4.
I have it 2 weeks drove it acouple of times so far, Well I have driven it a few times, on the way home the other, came up to a stop light, it changed green I pushed the gas and the car cutoff.
Put the car in Park, started up shifted to drive and it wanted to cut off and ran very slugish when you let off the gas it wanted to shut down the motor.
Got it home and checked to see if something came lose, wire vaccum etc. nothing, when I started the car up again and put it in gear is shut the motor down like it was locked up.
It has the lock up convertor kit no computer, disconnected power still locked up, is the torque convertor bad???
Submitted: 8 years ago.
Category: Classic Car
Expert:  Pragueress replied 8 years ago.

Problems like this is usually the torque converter clutch solenoid, and not the converter. Replacing the solenoid should help


Please hit the accept button if this helps

Customer: replied 8 years ago.


Thank you for the response, the question I would have is since the car has a custom lockup convertor kit that contains the solenoid, pressure switch in the valve body area, the vacum switch on the firewall which gets its power from the brake switch.

The kit was in the car when I got it, and it is from Speedway Motors which gets them from Painless wiring.

I called the tech line at Painless and he used his troubleshooting guide and said to disconnect the power from the brake switch since this is the only power soucre to the vacumm switch to the trans solenoid. I did this but it is still locked up.

My assumption is the Solenoid or switch in the trans is bad, but i am leaning towards the solenoid. Based on your feedback since this is a custom application would you recommend buying the parts for the kit and replacing it?

I am trying the cheapest route first and from what I have read on line the torque convertor would not be the problem but it would be the TCC switch, Mine does not have it so I would assume the solenoid is the same thing that sends the command to lock up the convertor.

Even with power removed if the solenoid is bad most my car buddys that have discussed it with a few transmission guys are saying the same thing its the solenoid.

I ma not a 700R4 expert so any advice that you can provide would be helpful.

The transmission guy is telling me over the phone it sounds like its in the valve body but before I go down that path I am willing to try the solenoid route first.



Expert:  Pragueress replied 8 years ago.

Forgive the delay in my reply as I had problems with my ISP.


Anytime I've seen a problem like yours it always was the solenoid and I would go that route in your case, and getting the part from the kit is recommended


Please hitthe accept button if this has helped

Pragueress and 3 other Classic Car Specialists are ready to help you