Is this what killed my Trans??

[Sleeper-6]

In a previous post we came to the conclusion that my 2-3 shift problem is being caused by the direct clutches going south. I picked up CKs book and plan on pulling the trans after the holidays to install and Billet forward drum and input shaft, along with dual feeding the direct clutches.
Out of curiosity I did a line pressure check today to see if I could find the cause my failure since so many have beat the same trans much harder and had them last longer. I found some interesting results.
Following the instructions in the book, here's what I got.

Min TV @ 1000 RPM
P-80
R-130
N-80
OD-80
D-80
2-125
1-125

Max TV @ 1000 RPM
P-175
R-140
N-170
OD-140
D-140
2-135
1-125

Since these pressures are so low I played around a little bit to see at what RPM the pressures would max out at Max TV. They're still Low.

P-200@1500 rpm
R-200@2500 rpm (best I could do, tires broke loose)
N-170@1500 rpm
OD-200@2300 rpm
D-200@1900 rpm
2-200@1900 rpm
1-175@1800 rpm

Definately some screwy readings, What do you guys think? I need some help on where to look when I take this mess apart next month

 

[77 cruiser]

Did you check hot or cold? I'd say excess clearance in the pump.

 

[Sleeper-6]

I checked hot, after driving around for 20 min or so.
That makes sense for the readings taken in the D and OD range, but what is causing the lack of pressure rise in Manual 1 and 2?

 

[bison]

Did you at any point change the pump? What procedures did you follow if you did?

 

[Sleeper-6]

I diddn't do the trans myself last time. I did bring it to Dynotech for a Hi-pro rebuild. I would assume it was at least visually inspected for any defects at the time. That was about 3 years and 18,000 miles ago.

 

[bison]

Conact Bruce about getting a complete ready to install pump assembly.

 

[chris718]

reverse boost pressure is not correct .check it at 1000 rpms with the cable pulled out and at rest.there is no ned to power brake the car during the test.this will only raise pressure if the pump pocket is severely worn .

 

[Sleeper-6]

That's what I did in the first and second set of pressures. 1000 RPMs at max TV and no TV. I'll go out and double check. (I left the gauge hooked up)

I was power breaking with the cable pulled out to max TV just to see where the numbers would climb to. That's the third set of pressures.

Back in a few........

 

[Sleeper-6]

Well, I rechecked and all my readings at Max TV were within 5 Psi of my previous post.

Final Pressures at Min TV were within 10 psi.

I did see something quite interesting. My first tests at Min TV were done while the car was still rather cold. My pressures in manual 1 and 2 went right to around 235 psi. Over the next few minuets they were steadly dropping off until I arrived at the final readings. I could not get them to repeat the high readings.
Something is definately going south as it warms up.

 

[chris718]

reverse pressure is low.how much psi drop on a 2/3 shift at wot?better yet 2/3 flare and low reverse psi.pull out the trans and fix it the third clutch is fried from the 2/3 flaring already.

 

[Sleeper-6]

I have yet to check the pressures at WOT I'm quite sure it will just blow right through the third gear shift WOT and not grab untill I let off. I did check at around 1/3 throttle, the 1-2 and 2-3 shift looks like just a quick twitch of the needle. It moves so fast that's it's nearly impsssable to take a reading it returns right back to where it started. I believe it was showing around 125-150 psi when it shifted. Pressure does not drop while it was slipping into third.

I know that it needs to come out and get at least the clutches done. I'm just trying to figure ut what else is wrong so I can fix that too. So far it's looking like the pump is shot too, or am I looking at a valve body/ pressure regulator system also?

If it's as simple as a chewed up or broken part I can spot that. I'm just looking for guidence on what particular parts may be causing my problems.

 

[chris718]

use the manual to find the direct clutch and upgrade it per the specs in the manual.youll find worn items according to how the manual explains there inspection.we also are now making an aluminum insert for the direct clutch that goes under the first steel to greatly improve third gear feel as well as heat transfer and speedy apply.

 

[bison]

I have yet to check the pressures at WOT I'm quite sure it will just blow right through the third gear shift WOT and not grab untill I let off. I did check at around 1/3 throttle, the 1-2 and 2-3 shift looks like just a quick twitch of the needle. It moves so fast that's it's nearly impsssable to take a reading it returns right back to where it started. I believe it was showing around 125-150 psi when it shifted. Pressure does not drop while it was slipping into third.

I know that it needs to come out and get at least the clutches done. I'm just trying to figure ut what else is wrong so I can fix that too. So far it's looking like the pump is shot too, or am I looking at a valve body/ pressure regulator system also?

If it's as simple as a chewed up or broken part I can spot that. I'm just looking for guidence on what particular parts may be causing my problems.

Disconnect the wastegate to get 2-3 pressures or with the car on a lift have someone pull the TV cable to max and just run it up to the 2-3 shift and record the pressures.

 

[chris718]

without a load on the driveshaft in the form of the weight of the car fighting its rotation and the road load and friction generated by the final drive the suspected pressure drop on a 2/3 shift wont be seen on the lift.

 

[Sleeper-6]

Thanks guys, I'll let you know what I find once I get this thing apart. I'm prob looking at a pump replacement. That aluminium insert sounds interesting, I'll definately be giving you a call once I see what else I need.