I have a 1965 Allis Chalmers TL-14 wheel loader. It has a TwinDisc power shift 4 gear (+ 4 reverse) transmission that seems to work fine in 1st gear but barely moves the loader in other gears. Clutches engagement is fine, I can definitely feel them engage and tractor creeps ahead/backwards, however in order to move at any appreciable rate it needs to be revved to the sky. Today I checked the pressure gauge (as I understand connected to the forward clutch pack) while cycling through the gears in idle, both forward and reverse. It behaves the same way - around 30-40psi in neutral, then move shifter to any gear and the pressure goes quickly up to 250psi and you can feel the clutch engaging. There is enough oil as can be seen through the sight gauge, it also looks good, ie light colour, no foam. I don't know when it was changed last time since I got the loader only recently. The fact that it behaves exactly the same in all 8 gears gives me hope that it is not clutch packs for gears 2,3 and 4 burnt/slipping. Or does it actually mean exactly that, say if the oil pressure creating part (pump/converter) is functioning fine but the clutches are gone? The pressure seems to be tad higher than the book states (150-220psi) but could be just the accuracy of the gauge. Also I took these readings when the oil was still cold. I know from different forums that when the strainer is plugged there is not enough oil for the pump to raise the pressure but in my case it seems that the pressure is not a problem? I did read somewhere to watch the driveshaft between converter and gearbox while in gear and not moving, the shaft should not move if the clutch is good. Did not try that today, is this a correct procedure? Can someone help me to troubleshoot this issue, I really want to bring the old girl back to life. Many thanks everyone.
Hi Jack, I'm definitely not an expert in TwinDisc t/m's. Anyway I feel halfway safe in countershaft powershift t/m's. I assume the Twindisc is also countershaft design and reading through your last sentences, converter is separate from t/m, possibly converter directly attached to flywheel housing. However this doesn't matter. With loader at standstill and gear engaged, the prop shaft between converter and t/m must not spin even with wide open throttle. Engine speed (WOT) should be same in all gears. They call it stall speed as turbine of converter is "stalled". This test is good to test clutches for ability of transmission of torque, but presumably it will not get you a step ahead in your issue. You are saying loader runs nicely in 1st F AND 1R? Somehow sluggish in 2nd, guess, even worse in 3rd and 4th. F and R? My fear is, one or two discs in K1 (or how they call clutch for 1st) are (slightly) warped and K1 is dragging in higher gears. 1st gear clutch got pretty high ratio and already little internal losses reduce driving performance a lot. Feels like something is braking. Is there a fine filter fitted in t/m circuit. If yes, cut it open and check for debris. But, a slightly warped clutch does not necessarily produce much debris. Hard to say what is wrong in your tranny.