Help - 4R70W - Jolt between third and fourth gear

[Orleans]

4R70W transmission (2000 Ford Explorer Limited 5.0) jolt between third and fourth gear . The jolt occurs in the ascending and descending exchanges , but only between those two gears .
This problem started happening the next day to buy the car after three hours on the road (190 miles).
So far we've found that the level of the transmission fluid was low , damaged pressure regulator and former car owner had never changed the transmission fluid or filter after 70k.
Any suggestions about the jolt between third and fourth gear are welcome.

 

[JK080]

That is a odd problem for this transmission.

How do you know the pressure regulator is damaged? The pressure regulator valve controls the pressure of the transmission, this can be the problem if its not working correctly.

 

[Orleans]

Thank you for your interest in helping me.
Sorry for the incomplete information. The regulator that is damaged is the fuel injector pressure regulator.
The engine could not maintain the idle working properly then I noticed that the vacuum hose was full of fuel. This can alter the functioning of the transmission?

See the picture of the damaged pressure regulator.

 

[JK080]

Well that makes more sense.

No that pressure regulator won't affect the transmission, there is a pressure regulator inside the transmission that can have problems, this can cause many different issues.

Jolt in 3-4 or 4-3 is unusual but a bump or shudder when the converter locks and unlocks is common. The converter is active in both 3rd and 4th, so maybe thats whats you are feeling. I would change the fluid, this usually takes care of converter engagement or shuddering problems. Additives that help address shudders and converter problems work well too, I would only use them if changing the fluid doesn't take care of the problem.

 

[Orleans]

I'm just hoping the filter and gasket arrive.
I will keep you informed about the progress of the service.
Thank you

 

[Orleans]

I removed the fluid from torque converter and oil pan (11 quarts).
I add new fluid with the engine off (11 quarts)?
Or with the engine running and the transmission in P?

 

[PopRichie77]

Put half in then start the engine, leave it idle and add the rest. Check the level before adding the last quart.

 

[Orleans]

Better late than never.
After changing the transmission fluid started functioning normally without shudder.
Thank you all for the great help.