4020 Powershift issue

[Pennerosa]

Hi there looking for some input. Had the tractor split last winter and replaced all the clutches and seals in the C1/C2/PTO basket. Got all back together and seemed to work great. A couple days ago I headed down the road with the hay bine to cut a field a few miles away, noticed that when I shifted into 8th gear that the PTO would engage enough to try and spin the hay bine (the PTO brake has never worked as long as I have had it). Thought I would look into it more when I got back. Cut fine with it for a couple hours in 2nd gear, then I went to shift up to move to another part of the field. Shifted it to 3rd, was good, then I meant to shift to fourth but hit a bump and shifted straight to 5th. There was a god-awful BANG and the tractor stalled out.

At first it would not re-start, it cranked slowly, and even with my foot on the inching pedal & the gear selector in neutral, the tractor was trying to creep forward when cranking. I slowly racked the shifter through all the forward and reverse gears, and finally it seemed to go into neutral. It started, but if I tried to put it into any gear it would stall out the engine as soon as I let the inching pedal up. Racked through all the gears again with engine off, tried it again. It started to move in first gear, but heard crunching noises, then another bang, and then it started to drive normally.

Now I have 1st and 2nd gear (forward and reverse) but nothing in any other gear, and no bad noises. At least that was enough to load it on a trailer and get it back home! I looked in the manual and I see that 1st and 2nd use only the C1 clutch, and the rest of the gears either use C2 or a combination of C1 & C2. I am assuming something either broke in the C2 part, or there is something wrong in the spool valve feeding the C2 system? Any input appreciated, thanks.

 

[Scott 730]

I am no PS guru, but I do own one and had some issues that needed expert help. Was the shift valve removed and cleaned when you had it split? Sticky spools can cause all kinds of strange behavior with a PS. I would start with pressure checks in all gears, and check shift valve for sticky parts. My opinion only.... YMMV.

P.S. Wondering why you didn't fix the PTO brake when you had it split??

 

[Pennerosa]

thanks. 2 reasons about the PTO brake:

1) I was out of money and did not want to tackle the 2nd split required to do it
2) the conditions I work in with lots of little parcels I am constantly taking the PTO in & out which is hard on the brake anyway

 

[brendonh]

C2 Exploded is my guess.

 

[JIM MN]

I agree with a problem in the shift valves causing something coming apart in the C-2 planetary. Or, and maybe C-1? A sticking shift valve can direct oil to the wrong port at the wrong time? Do some trouble-shooting.

 

[Pennerosa]

Well I will be splitting the tractor. Bought some pressure gauges and went through the tests, all pressures are good. However, when I took out the C2 test plug, a bunch of black crap came out, looked like clutch material. Obviously I will need to also disassemble the shifter assembly and clean/check the spools. My guess is some of that crap made the valve stick - even though it is working properly right now.
I will also us JD parts this time, I put in an aftermarket clutch kit from Diamond Tractor and I was not really impressed at the quality of the parts, but I thought they would last longer than 5 hours!

 

[Tx Jim]

If trans pressure tests are within spec's & trans is operating correctly I'm curious why you state your going to split this 4020? The loose material you located could be from the original failure/repair.

 

[brendonh]

when you drain the oil, show us the sump screen and the shiny stuff that went "thunk" in the bucket. please.

Also, I dunno anything about non-deere clutch parts for these 8 speeds. All of these I rebuilt were with deere parts since I was working as a tech at a dealership back then. I do know that Super HTB (used to be from the Co-op, Farmland Industries and was blue.) along with all forms of "universal tractor oil" would eat the glue that held the friction material to the steel backer that was a deere facing disk. I beg of anyone with a deere powershift to use HyGard in it.

 

[Scott 730]

If trans pressure tests are within spec's & trans is operating correctly I'm curious why you state your going to split this 4020? The loose material you located could be from the original failure/repair.

^^^^This^^^^. Clean the shift valve. Change filters and check the sump screen. Inspect filters for debris. Remember the KISS principle. Do the easy stuff first.

 

[Pennerosa]

I need to split the tractor because even though the pressures are in spec the C2 is gone. I only have 1st and 2nd gear, which use C1, every other gear that uses C2 slips and barely moves.
Interesting point, Brendonh I just used universal tractor oil, my local JD dealer told me I did not need to use HyGard in something this old, and the farm I work on has lots of the universal stuff laying around so I just used it. I will use HyGard going forward once I get this figured out.

 

[Tx Jim]

my local JD dealer told me I did not need to use HyGard in something this old, and the farm I work on has lots of the universal stuff laying around so I just used it. I will use HyGard going forward once I get this figured out.

Your local JD is incorrect. You should only use HY-Gard or hyd oil that meets J20C specifications

 

[wore out]

when you drain the oil, show us the sump screen and the shiny stuff that went "thunk" in the bucket. please.

Also, I dunno anything about non-deere clutch parts for these 8 speeds. All of these I rebuilt were with deere parts since I was working as a tech at a dealership back then. I do know that Super HTB (used to be from the Co-op, Farmland Industries and was blue.) along with all forms of "universal tractor oil" would eat the glue that held the friction material to the steel backer that was a deere facing disk. I beg of anyone with a deere powershift to use HyGard in it.

IIRC, the C1 and C2 and PTO lined plates are made of sintered bronze on steel and shouldn't be affected by oil choice.

The service brake pads are another matter, though!

 

[Pennerosa]

Well I got the tractor split and its bad. The clutch basket actually looks ok but the C2 shaft from the clutch basket into the transmission blew apart. Do not have a smart phone so I do not know how to send a picture, it is pretty impressive (in a sad way). I will have to do the 2nd split as well I can see more damage in there. When I hit that bump and accidentally bumped the shifter up another gear the tractor was right in the middle of a shift, somehow it must have locked something up as if trying to be in two gears at the same time? Think I better find a backup tractor this wont be fixed in time to finish haying.... Oh well.... Oddly enough, there was hardly any shrapnel in the oil at all, not even any in the pickup screen. Pretty clean break actually.

 

[used red MN]

Do not have a smart phone so I do not know how to send a picture, it is pretty impressive (in a sad way).

If you have a digital camera take photos with that and save them on your computer. The “Attach Files” button at the lower left will take you to access your folder (browse to) where the folders are stored.

 

[Rystoltenberg11]

Your local JD is incorrect. You should only use HY-Gard or hyd oil that meets J20C specifications

We don’t use hygard. Dealer said if you use an equivalent than you will be fine. So we use chevron 1000THF

 

[Tx Jim]

We don’t use hygard. Dealer said if you use an equivalent than you will be fine. So we use chevron 1000THF

Any hyd oil that meets spec's of J20C is fine for JD closed center hyd systems on JD tractors between 1965-1992 which includes Chevron 1000THF