While pushing some small trees the left side acted like it jumped to neutral and wouldn't pull in any range or reverse. fluid level was ok and filters didn't have many hours on them. let it cool off then it worked fine until it warmed up again, usually after 10-15 mins. checked linkage for binding, drained trans and sent oil sample off (oil was fine), replaced filters again but same thing. dealer came out and checked pressures on trans control valve, rh side was 260-280, lh side was 150 and gradually fell as it warmed up. took valve off and lh spool has minor scoring on it, so Im guessing thats the problem. the spools are a metal to metal fit in the bore. however, a new spool is $600, not sure if it would work because of bore in valve could be bad also. was going to get a new valve, but Case in their infinite wisdom went from $1700 on their 125588A4 version to $11,000 on their 125588A5 version. Anyone have a new A4 valve laying around or any other ideas?
Welcome to HEF @professionallywrong I wouldn't pull the trigger on a new control valve without doing more testing. The 1150H uses teflon oil control rings on the end of the transmission shafts & it's a common problem that these wear thin & cause oil pressure loss & drive hesitation issues. I have clients with 1150H's with well over 10 000 hrs on them & still using original transmission control valves. It is possible there could be issues with the valve spools as they have internal valves & springs - but more testing would be required. I would check the pressure going into LH clutch packs NOT by Teeing into them but directly into the feed lines to see if the pressure was the same as the rest of the system. You need to figure if the pressure loss is in the LH FWD/REV end cap OR the LH HI/LOW end cap or maybe both??
We took the plugs out of the top of the control valve and added pressure gauges there. I have had a teflon ring go bad but it only effected one speed on one side (I. E. high or low), not all speeds in forward and reverse. I removed the end caps on the rear out of curiosity and they looked fine... The valve is the only thing I can think of that would make everything on the left side bad...
Good you checked the rear end cap. It's still possible that the HI/LOW end cap may still be at fault - depending on what has gone wrong in there. It has to be in HI or LOW to drive & depending on which ring has gone, it may affect both of them & explain the loss of drive. .......Just a thought - nothing worse than spending thousands & find you still have the same problem.
Which one is the hi/low end cap? I see two on the back of the trans (left and right) and two on the front (left and right)
Check and make sure your brake pedals are fully returning. When pressed lightly they declutch the transmission on one or both sides depending which pedal you push. The spools in the valve get stuck sometimes and causes the weak drive or no drive on one or both sides. The spools are behind where the brake lines bolt to valve. You can remove your brake lines and check spools with a screwdriver. If the right side works fine put the screw driver in the hole and push the spool, it will be under spring tension you will feel resistance then let off it will pop back into place, now try the left side I bet it either doesn't move because it is stuck or it moves too easily bad Quad rings or spring broken. Just a thought.
thanks for all the replies! I checked the brake spools, the springs are fine, disassembled the spools they look fine. there aren't any quad rings in the spool, its just a metal to metal fit in there....any more ideas?
Minor scoring on a valve will not cause this problem, as said above check all rings and pressures.
Did you check the caps inner bore when you checked the seal rings? I’ve seen those bores worn so badly that new seal rings wouldn’t stop the leakage.
I didn't mike the bores of the end caps on the back of the transmission, but there was no groove there of any sort, they seemed to fit snug. which one is the hi/low cap? I'll go there next...
Test sheet for you. May help you narrow down the cause without pulling caps off.
OK thanks! we did pressure tests but not all what it said. what we did was watch the left and right pressures in all gears. RH stayed consistent 260-280 psi in each range/gear. LH started about 160 in all ranges/gears then dropped off as it warmed up. we didn't do all these steps. thanks for the info!