How to: Using a Transmission Pressure Gauge

[Glacier991]

YOur Q as I read it is essentially: "Would increasing pump pressure improve TC shudder issues"... I'm not going to weigh in as some expert on this one... but let me offer my thoughts in the "for whatever they might be worth" category. In the 5R series, line pressure is dictated not so much by the pump per se (assuming it is putting out adequate pressure) but by the pressure regulator valve and the electronic pressure control solenoid (EPC). That solenoid can vary pressure by having different voltages applied to it (and/or modulated) as I best understand it. IN fact, in the 5R the TCC lockup solenoid in itself is programmed to modulate slippage IN THE TCC CLUTCH APPLICATION to make for smoother engagements (true! Brain and I could not believe it)... so .... in short the answer to your question as posed, is likely ..."probably not".

 

[mctoy]

Makes perfect Ford sense to me...a transmission designed to slip!!!
Thanks 'G'.

 

[Glacier991]

In fairness to FORD (and GM, Toyota, Chrysler etc etc) there are competing factors at work here... the engineer wants a resaonably fast shift, minimize slippage and wear and heat... but not so fast it jars other potentially sensitive gear train components beyond their ability to stand it. Mom and Dad, Grandma and Joe average has learned to expect silky smooth transitions between gear changes... and thinks anything more harsh than that is "something wrong", but either way prefers the smooth ones.

Engineers are not buying the cars en masse. The masses are. Guess which one wins the design contest? Bingo. Modulated TCC engagement. (Brain says there might be a very very very very teensy mpg issue at play here - I'll let HIM explain that one).

Which brings us to shift kits. Full circle.

 

[Glacier991]

Shudder is not exclusively a pressure issue. The science of what happens at the interface in a wet clutch is pretty technical. Would more pressure help shudder? Probably. Is pressure the sole culprit? no.

 

[Glacier991]

I stickied this, for now.

 

[BrooklynBay]

Here is an article in the January/February issue of Gears Magazine on taking pressure readings: Dead Link Removed

 

[easydusit]

Man a guy could get smart reading this stuff!
I better be careful. LOL
Thanks so much for all the great info!

 

[Glacier991]

Thanks for the kind words. Glad you find it helpful.

 

[merlin12volt]

WHY IN SWEET ZEUS' GOLD IS THIS NOT STICKIED IN THE TRANS SECTION?

I have a couple of questions about this and would like some help.

1994 Explorer auto 4wd slips when going from 2-3 gear (not sure if it is the "flare" everyone is talking about because there is no real explanation as to exactly what the "flare" is?)

I plan to get a transmission pressure kit and check the pressures and see what I come up with. From what I gather if the pressure is there, that means that the issue is probably with 3rd gear itself. If the pressure is low it points to something probably in the valve body correct?

Good work on the write up and explanation of this. The gears magazine links are dead so does anyone have those on hand so I may look over them. Thanks again

 

[BrooklynBay]

I have the Gears Magazine PDFs. What's your email address so I could send them to you? I'll make this thread a sticky.

 

[merlin12volt]

Thanks Brooklyn, send them to merlin12volt@comcast.net

 

[BrooklynBay]

Check your email. You should have two PDFs.

 

[kkrocks]

you seem to know quite a bit about transmissions, what do you know about vacuum hoses and placement??

 

[BrooklynBay]

Check the vacuum hose routing diagram under the hood. Your transmission doesn't have a vacuum modulator.

 

[greasemanicure]

4r and 5r pressures

Are the pressures for the A4 representative of what I'll get on my 4R? I started a thread on the tranny problems (big slippage in reverse) in the Trans forum. I will be taking pressure readings tomorrow evening.

Thanks!

 

[BrooklynBay]

Those transmissions have an additional EPC pressure port.

 

[greasemanicure]

EPC Pressure Port

Thanks for the heads up. Where would it be relative to the one where the one to the right of the manual shift shaft? Is that where I should be measuring the pressure?

 

[BrooklynBay]

The main pressure tap is on the rear driver's side, and the EPC pressure tap is on the rear passenger's side.

 

[greasemanicure]

EPC Port

Thanks! I posted my pressures from the main port drive in the thread I started in the transmissions forum. I'd appreciate your comments on the measurements.
Joe

 

[zero_psi]

Ben, close. 1/8" NPT.

will a temp gauge screw in there?