Late 4020 power shift reverse problem

[Scott 730]

Got the diamond in the rough 4020 that I have posted about previously running today. Sorted out a few electrical gremlins to get it turning over with the key, then cleaned up and resealed the injector pump. Forward speeds seem to work fine, but all 4 reverse speeds seem to have a lot of slippage. It will barely pull itself in reverse from a stop on level ground. I have the tech manual and it seems that B3 is in play in all reverse speeds. Does anyone have any insight as to possible causes before I start pressure testing? Thank you.

 

[tim s]

how does it do in 7th

 

[tim s]

here is a chart

 

[Scott 730]

(quoted from post at 19:40:46 09/28/17) how does it do in 7th

It seemed OK driving around the yard, both upshifting and downshifting. Actually seemed real good in all forward speeds.
One other thing, when in reverse, when you start applying the brakes it stops dead, sounds and feels like the light brake application is making a clutch pack disengage. Does this sound possible?

 

[tim s]

I would say it is just the brake holding it back. I had one a while back that all the bolts holding the c3 pack
had broke, letting it fail.

 

[rick deere]

have you serviced the trans and changed filters and cleaned the screen.

 

[Tx Jim]

Check to be sure gearshift linkage is fully shifting control valve into reverse gears

 

[Scott 730]

Filters and screen are on the list of things to be done. As this tractor had been sitting for about 8 years, the first priority was to get it running. Now start chasing other issues that come up.
I believe the linkage is shifting fine. Lever moves easily from forward to reverse. The arm going into the trans case makes an audible click when the detents hit forward or reverse.

 

[rick deere]

thats your problem. keep us posted

 

[rick deere]

and only use john deere high guard nothing else and john deere filters.

 

[Scott 730]

Update time. Replaced both filters and looked at the sump screen. The screen was virtually spotless and nothing unusual with either of the filters. After driving around the yard and up the drive for awhile the reverse speeds started working normally, crisp engagement from neutral and pulled hard when applying the brakes. Then it decided to go back to slipping from a stop again. I got it to work properly on 2 occasions today, engaging it numerous times before starting to slip again. When it slips from a stop going into reverse it will lock up in gear after a few feet on level ground. Will not pull up any grade at all. When backing up after these "soft" starts, if you apply the brakes it feels just like pushing the inch pedal. It feels like there is something disconnecting in the trans.

I suppose the next step is pressure testing. My tech manual says to check pressures with the tow lever disengaged and the tractor on blocks. Can these tests be done when driving the tractor if I put a hose on the gauge so I can see pressures as I drive?
My other thought is to just hook up to the field cultivator and work it awhile. Maybe it just needs some exercise and a good heating up to get things working after sitting for 8 years or so. Thank all of you for your help and advice.

 

[Hay maker2]

(quoted from post at 02:12:41 10/05/17) Update time. Replaced both filters and looked at the sump screen. The screen was virtually spotless and nothing unusual with either of the filters. After driving around the yard and up the drive for awhile the reverse speeds started working normally, crisp engagement from neutral and pulled hard when applying the brakes. Then it decided to go back to slipping from a stop again. I got it to work properly on 2 occasions today, engaging it numerous times before starting to slip again. When it slips from a stop going into reverse it will lock up in gear after a few feet on level ground. Will not pull up any grade at all. When backing up after these "soft" starts, if you apply the brakes it feels just like pushing the inch pedal. It feels like there is something disconnecting in the trans.

I suppose the next step is pressure testing. My tech manual says to check pressures with the tow lever disengaged and the tractor on blocks. Can these tests be done when driving the tractor if I put a hose on the gauge so I can see pressures as I drive?
My other thought is to just hook up to the field cultivator and work it awhile. Maybe it just needs some exercise and a good heating up to get things working after sitting for 8 years or so. Thank all of you for your help and advice.

Having the tractor up on blocks is a safety when checking the pressures. When the tow lever is pushed forwards it disengaes the rear end; in the event that the tractor is not on blocks and the tow lever gets pushed back while testing pressures this will damage the gears and coupler and may run you over causing severe pain, discomfortment and even death.

I rebuilt my 4020 Powersfhift a few years ago. It was not to bad of a job.