D7E 48A noisy scavenge pump

DO NOT shim up the inlet relief valve, it is there to protect the converter from too much pressure on cold starts and is bench set. 90psi is quite normal. Trying to shim it up could cause the converter to burst, I have seen this happen after a converter failure when bits from the old one were still blocking the cooler.

I should say 90psi was normal but it could be much less when the machine gets hotter depending on ambient temp. What do you mean by scavenge pump? this is down under the drive shaft!!.
If you have adequate outlet relief valve pressure and everything works properly, there is little wrong with the machine.

110 to 120 psi bench setting for the torque converter inlet relief is correct for 48A6393-up.
Those readings seem normal.
What are you getting for direction clutch pressures? (should be 50 to 60 psi less than speed clutch pressure).
Also what are you getting for transmission lube oil pressure? That reflects end of the line pressure for the system and should read 9 to 15 psi.
What is the torque converter outlet pressure? Should be 37 to 47 psi maximum with selector in third speed forward, brakes activated and converter stalled.

I started a new post with the specs for this transmission. I did this so the specs would be easy to find in future searches.
Craig

Sorry for the long time between posts. Here is the update for this machine. We have now replaced the torque converter and got the transmission rebuilt, it was in bad shape. We still have a noisy torque converter recirculation pump/scavenge pump and low transmission lubrication pressure. Here are the pressures we have at hot, high idle: pump pressure 350psi, TC inlet 62psi, TC outlet 45psi, transmission lube 2.5psi. We are thinking we have a restriction between the torque converter and transmission. We put a gauge on the lid of the magnetic strainer before the oil cooler and on the outlet side of the oil cooler. The pressures when it was warmed up a bit (not fully) and high idle were: magnetic strainer 45psi, oil cooler outlet 25psi, and 11psi on the transmission lube.

So we figure we have a restriction around the oil cooler somewhere. What we could use more information about is what the pressure drop over the oil cooler should be (we have about a 20psi drop right now at high idle) and also how much pressure the recirculation pump could possible take out of that line.

Thanks in advance guys

You mentioned the noise goes away when you pull the steering levers, have you gone through the steering clutch control/booster? Does it release the clutches like it should?

Cool D7E 48A 6393 - UP transmission specs...
These pages are from the Caterpillar Testing and Adjusting Power Shift Transmissions manual.
Click image for larger version.
[attachment=51580]IMG.jpg[/attachment] [attachment=51581]IMG_0001.jpg[/attachment] [attachment=51582]IMG_0002.jpg[/attachment] [attachment=51583]IMG_0003.jpg[/attachment]
I hope this helps,
Craig

Cool D7E 48A 6393 - UP transmission specs...
These pages are from the Caterpillar Testing and Adjusting Power Shift Transmissions manual.
Click image for larger version.
[attachment=51580]IMG.jpg[/attachment] [attachment=51581]IMG_0001.jpg[/attachment] [attachment=51582]IMG_0002.jpg[/attachment] [attachment=51583]IMG_0003.jpg[/attachment]
I hope this helps,
Craig

Hi Team,
I cannot say I have ever heard a noisy TC Scav. pump what with all the noise around that area.

Given that the scav. pump only pumps the leakage oil from the TC seals it therefore would pump mostly air/aerated oil, unrestricted back into the front of the main PS Trans case.
If there is a restriction to this return pump flow then pressure would be built up and so it could sound like it is pumping marbles into a tin can--if this is so then there is likely a restriction in its return hose and/or system.

Oil that is aerated and being pumped at pressure will sound like marbles being pumped, from memory, the return hose goes back to the main powershift trans case on its front wall and so should be free flowing without restriction and so should not make the marble pumping noise that occurs when aerated oil is pumped at pressure.

The TC scav. pump shaft can be bent if it is left installed on the the main TC housing when said housing is removed from the engine, as the TC drops down onto the pump drive gear and bends the shaft.
The Scav. pump also should not be installed until after the main TC housing is refitted to the engine also to prevent the shaft being bent by the weight of the TC resting on it.

Also at least 1 to 2 gallons of oil should be put into the main TC housing for the scav. pump to pump until the TC leaks enough oil for the Scav. pump to pick up or it can overheat from running dry and seize up--seen both many times over the years.

Hope this helps.
Cheers,
Eddie B.