Can anyone look up the part number for the scavenge pump for the TC? S/N is 86j4873 Thanks, Justin
I'm not seeing a pump referenced as a "scavenger pump" just this one:
How many pumps are in these transmissions?
Don't think these have a scavenge pump, torque is in transmission. Bob
Attaching a few pages out of the "Systems Operation" section of manual showing the power-train components.
Having a issue with the transmission getting hot after an hour of operating. Already ruled out the thermostat before cooler and cooler was cleaned when I had radiator out. I was told they have a pump to keep the converter from filling up and that it might be bad. I've never messed with the transmission on it so I really don't know.
If it's not the oil cooler, low transmission oil pump flow from a worn out transmission pump will cause overheating. Pump pressure should be 275psi minimum, Max 305 +/-15 psi. Check pressure at pump or filter cover. Also check suction screen in the transmission.
I'll check the pressure and see what it is. I had the suction screen out 125 hours ago and it was clean. I noticed today that it has a noise and I believe it is coming from that oil pump location. The overheating has slowly gotten worse. I had put a new temp gauge in when I checked the screen. When it runs hot, the inlet line running to the cooler reads around 250 degrees F with temp gun. It doesn't get sluggish though, still shifts & pulls fine.
Correct, not like some Cat applications the Converter is inside the same housing as the transmission so there is no need for the scavenger pump like on say a D6C.
Okay, below are the sections out of the Cat manual on trouble shooting referencing over heating converter and transmission:
Odd that they leave out checking the transmission suction strainer. Fairly common source of flow problem. I guess that's what comes from universal trouble shooting literature that is not model specific. Plus old stuff!!!!
Very true! That should have been one of the sub-steps under #7 Not enough oil to torque converter. And actually #7 might have been better if it had been #1 on the list as I always tried to do most of my trouble shooting starting with two ideas. Start with the easy things to check and then with the cheap things to check. Sometimes being lazy and a tightwad is the best place to start from when trouble shooting a problem.
Check pump pressure at filter housing, 100 psi at WOT. Guess I'll pull the pump and see what kinda damage it has, if any. I'm going to pull the screen and filter also.
Got the pump out and taken apart. What you guys think? Worn pump and losing pressure through them eroded bushings?
If clearance between the cover and the gear face is 0.004" or more pump is shot.
Measuring .007"
Definitely qualifies as worn out. New is 0.001" sometimes less to 0.003" Gear tip to housing clearance is 0.001" to 0.002" (also worn out at 0.004") Gear backlash should be about 0.020" Max although that's not all that critical
While I will not doubt that the pump is worn out and needs to be replaced I still have to wonder if there isn't some other problem. I know I would be checking the suction side of that system very close for either a suction leak or some kind of restriction. Also if on start-up with new pump it does not jump up to 300 psi in a matter of a few seconds I would be looking for another problem. Say the control valve that regulates the oil pressure.
Be sure to fill/prime the pump with oil before start up.
I cheat on a dry startup replacement pump, I pack the pump with lubriplate or similar grease.
Update on my oil pressure issue. Replace oil pump with Cat Reman pump & pulled suction screen to check it, no debris. Replaced filter, topped off transmission oil. Cranked machine up and had oil pressure within 4 seconds. Problem is that I still have the same oil pressure as before, 50 psi at idle and no more than 100 psi at high idle. Possible relief valve bad?Where is the pressure relief valve at on these machines?