What relates the fluid pressure in the 2003 Explorer Transmission and or Torque Converter? From what I have read so far, it appears that the Torque Converter will not function properly if the fluid pressure is not at the correct level. Is this also true for the Transmission?


If this is true, what regulates the fluid pressure? is it internal to the Torque Converter? Inside the transmission? or is there a regulator mounted external to the transmission? I like the last option the best!


Please help me understand.


Thanks.

 

It's complex. There is a pressure regulating solenoid, but a lot of regulation is done by controlled leaks in the system.
The torque converter doesn't need much if any pressure, it just needs to be full, and the rotation of the shell vs the stator vs the impeller is what makes it work.
The better question may be what is the issue that leads you to suspect a pressure problem?

 

I posted this under Torque Converter or Tranny?


Last year we bought a well used (not well taken care of) 2003 Explorer XLT. Since this is really my son's truck, I do not drive it very much (unless I need to tow something or fix it lol). Seems to have been driving fine for months till today. Although, most likely some of the symptoms have probably been randomly appearing for a while but easily ignored by a relatively new driver.


Feels like it does not want to shift. It revs fine taking RPMs to over 4k in park; however, NO POWER when in gear (most of the time)! RPMs seem to stay about 2k or so but occasionally spiked to 4k or so without a change in gears, almost like it went into neutral. I let go of the gas and tapped it, it then went back into gear but still powerless, chugging along.
Very inconsistent!

I put my code reader on it, but there are no codes. Oil is at correct level and actually kinda clean.
I did a transmission fluid change almost a year ago dropped the pan and replaced filter too. Checked tranny pan bolts and drain plug... no leaks.

Checked the front differential (looked like it was leaking) and found fluid low, added appropriate fluid.
Seems to engage 4x4 Low, 4x4 HI and out again.

I did check the transfer case fluid and it was a little low, filled it again. this was also checked in February along with both diffs and transmission.

We have historically had a clanking from somewhere near (or in ) the transfer case or Torque Converter. Used a stethoscope on it when I changed the trans fluid and could not really pin point where it is coming from.

The weather did just get cold...not sure if this is a coincidence or contributing factor.
I understand low pressure in Transmission or Torque Converter can keep them from working properly.
Am I rebuilding a transmission next month.
Or could it be the torque converter??

Any ideas, thoughts or comments are very much appreciated.
Thanks

 

I think you are describing an engine problem.

The transmission pressure is regulated by the main regulator valve in the valve body. This valve is Co trolled by the Electronic Pressure Control solenoid. This solenoid is controlled by the Power train control module. You are not describing a pressure problem.

 

I would so prefer that to Torque Converter or Tranny!


What kind of tests do I need to run to isolate the problem?


At least hubby bought me a new floor jack for my birthday! lol Just in time to fix the truck!


Thanks!

 

When you say chugging, it sounds like an engine issue. Is it just smoothly not giving any power, is the engine free revving in gear, or does it shake, not rev very high, etc?

 

There is a bit of chugging going up hills. Smooth going flat or down.


I expected to see some codes if an engine issue is that noticeable.


Someone suggested a vacuum issue. I replaced a vacuum hose and Intake manifold in January to get it to run. Perhaps there is another one.
I will look for some incense and do a smoke test.


Any other possibilities?

 

I am driving a POS GMC for work now that misfires like crazy, pops out the intake and farts when it shifts out of first gear, no check engine light. Sometimes the computer just doesn't know what's going on.
When was the last tuneup?

 

I (had son help) we rebuilt the car in January (did not run when we bought it) so as part of getting it on the road, changed plugs, fuel filter, cleaned throttle body, cleaned MAFS, replaced EGR, replaced 1 vacuum hose under the hood and a couple in cabin, replaced intake manifold, and valve cover gasket. The major repairs were exhaust (entire y) and radiator. The rest were fluids (oil, tranny, transfer case, and front and rear diffs.)