Hey guys, I am working on a vc60e cat forklift, LP fuel. The transmission has started slipping some, especially noticeable on a grade or softer ground. I did some testing, my pump pressure is around 140 PSI, but forward and reverse pressure is in the 35 PSI range. obviously very low. I have tried using anywere from 10 to 50 weight oil in the trans, makes no significant difference on the press. readings. I have replaced the trans. filter, and the neutral brake pedal is functioning correctly, not binding. I took it out first thing and cleaned it. does anyone know what might be going on, and what to check next?
does anyone know what I can check next?
Well I have been driving this lift for a few months now, it is still slipping badly. what can I do to check the transmission?
I don't have a hydraulic schematic for that transmission but, if the inching valve isn't the problem and without service information you are down to disassembly and inspection. As long as mainline pressure is within specs you could have seal rings broken or badly worn, piston seals in the clutch pack worn, or a problem in the valve body. What is the pressure spec for fwd and rev?
It should be around 100psi.
Have you pulled the screen/filter (if it has one) and checked for clutch material particles in it..?
Find yourself a breakdown on the valve body. If I remember correctly they used a valve to control the severity of the shift when going from forward to reverse and vise verse when not using the inching pedal . If it is stuck or the spring is broke it will bypass some of the pack apply flow and lower the resulting pressure. This may or may not be the problem and I may be thinking of another transmission. Just too many through the years.
Yes I have had it out and replaced the fluid. I never saw anything.
Thanks ok I will try that. That kinda sounds like the problem.
OK, so that would appear to rule out a major clutch failure. In that case the control valve would appear to be the best bet.
OK great! I've got ahold of my dealer, they are getting together the breakdowns for me.
OK just wanted to update. I ended up pulling the valve body on top of the trans. the gasket had a small place were it was missing, due i guess to age. i cleaned the pistons and used a new gasket, it worked fine. . for a litte bit. then it was slipping again. I eventually found within one of the pistons in the valve body, there is an orifice with a very small screen. (looked like a plastic plug in the center) the screen must have had a little junk in it, because once that was cleaned out, it has not slipped since. (been about 8 months now) thanks guys for your help!!!