OP
GaryBDavis
Gold Member
Here's the final resolution. There were three things that I had to fix to get the MFWD working (was stuck in MFWD, 2WD mode would not work).
1. CCU calibration, more like provisioning the MFWD feature thereby turning it on. BTW, 12V is applied to the solenoid when it's not turn on in the CCU. Someone replaced the CCU and never provisioned it which can be done using the turn signal levers in diagnostic mode (fuse location insert), no JD laptop required.
2. Bent hydraulic solenoid valve. There is a steel line that feeds hydraulic pressure to an external valve on the MFWD clutch housing. The tractor hit something it was slightly bent causing it to not work properly. You can test this by removing the valve with solenoid still attached and apply 12V to it. You will see it move (or not). Operating that valve is what puts it into 2WD. I replaced that valve at $270.
3. Seals blown/missing in MFWD clutch. At the suggestion of a savvy transmission mechanic, I pressure tested the clutch before putting it back in the tractor. Good thing I did because the seals were gone. By that I mean no evidence of the two shaft o-rings ever being there. The clutch packs had absolutely no wear on them so either the factory missed them or someone was in there already and didn't put them back. The other possibility is they disintegrated and left no trace but with no wear to the clutch packs, I doubt that. I replaced all the seals while I was in there. Cost was $60.
I had to purchase the JD TM1653 repair manual to show how to disassemble and reassemble the clutch pack and get the minimum pressure specs for manually testing the clutch piston. I had a transmission guru come in to help with that part and he could have done it without the manual but it's always good to have that reference.
I had three places this tractor was leaking trans-hydraulic. Where the MFWD clutch housing bolted to the gear box and two shaft seal o-rings in the gear box. So, I got that fixed in the process. No more leaks!
1. CCU calibration, more like provisioning the MFWD feature thereby turning it on. BTW, 12V is applied to the solenoid when it's not turn on in the CCU. Someone replaced the CCU and never provisioned it which can be done using the turn signal levers in diagnostic mode (fuse location insert), no JD laptop required.
2. Bent hydraulic solenoid valve. There is a steel line that feeds hydraulic pressure to an external valve on the MFWD clutch housing. The tractor hit something it was slightly bent causing it to not work properly. You can test this by removing the valve with solenoid still attached and apply 12V to it. You will see it move (or not). Operating that valve is what puts it into 2WD. I replaced that valve at $270.
3. Seals blown/missing in MFWD clutch. At the suggestion of a savvy transmission mechanic, I pressure tested the clutch before putting it back in the tractor. Good thing I did because the seals were gone. By that I mean no evidence of the two shaft o-rings ever being there. The clutch packs had absolutely no wear on them so either the factory missed them or someone was in there already and didn't put them back. The other possibility is they disintegrated and left no trace but with no wear to the clutch packs, I doubt that. I replaced all the seals while I was in there. Cost was $60.
I had to purchase the JD TM1653 repair manual to show how to disassemble and reassemble the clutch pack and get the minimum pressure specs for manually testing the clutch piston. I had a transmission guru come in to help with that part and he could have done it without the manual but it's always good to have that reference.
I had three places this tractor was leaking trans-hydraulic. Where the MFWD clutch housing bolted to the gear box and two shaft seal o-rings in the gear box. So, I got that fixed in the process. No more leaks!
