This is the pump and pressure regulator used in my Clark transmission. Can anyone point me to the parts I need to look at that could cause this unit to loose it's prime? Takes about two hours sitting to loose it. I do have the 480 page manual coming, but I don't know if it is going to help. Someone's experience may be the best help. Thanks.
Sounds like the charge pump is worn out or air is getting into the suction line somewhere. Is the converter part of the trans or is it seperate?
Yes, the converter housing is bolted directly to the transmission. After you get the prime up, it will drive just fine all day long, unless you let it sit for a couple of hours. It did this for 3 years until the hydraulic pump quit in 2009. Just now got it going again and the problem is worse as it takes longer to get going at start up. Found that you can pull the filter before you start it and the filter will be empty. You can fill the filter through the test plug and it will take right off.
Have you cleaned the suction screen, if it is clogged that can cause hard to get prime? You changed the hydraulic pump, that doesn't affect prime, that is the charge pump between between the filter housing and the trans case that charges the trans clutch pressure and the converter. Is the oil level up and how do you check it? It is checked in neutral at low idle with hot oil.
Check trans oil hot, unit idling and sitting level in neutral. Changed Hydraulic pump after it blew shaft seal. That sent fluid into transmission causing it to overfill and run out of trans breather. Can't manually clean suction screen without pulling transmission. Number 1 in picture is suction tube.
The Transmissions I dealt with were long drop and had removable suction screen behind the drain plug, sorry about that. Another possibility is where the suction tube goes through the trans case behind the charge pump could have worked loose and is sucking air, the tube is swagged at the factory and I think there is an oring that seals against the face of the charge pump, Clark had a tool to fix that. The problem could still be the charge pump itself is worn out. What oil are you using, Clark came out changing from ATF to 30W engine oil with temps 30 degrees F and up, 10W engine oil -10 degrees F and up or C2 trans fluid, ATF Dexron not Dexron II -30 degrees F and up. Don't know if whoever built your machine passed that change on. By the way what brand is your TLB?
Trans oil is Ford M-2C48-A year round. The PM I sent, I thought had the type machine, but it is Ford 6500 TLB. Transmission and hydraulic fluid is the same. Ford seems to be the only one who used this type strainer, "Ford's better idea". They also changed several things in the pressure regulator valve, but they don't seem to make any difference. I intend to pour varsol back through the suction tube to try to clean it some, and put suction pump on that tube to check for leaks. I am thinking that I have a bypass valve or relief valve in this regulator that may be stuck open. I have new springs and seats to put in. Again, thanks for your help and insight.
I don't see how you can put suction on that tube without blocking the suction screen off.
My intent is to put a pump in with a return to the sump and look for any signs of loss of suction. I'll have a anti-syphon valve between the pump and the return to check for any leaks in the suction tube.