John Deere 4020 Powershift Transmission

[Swamp Monster 33]

Hi Folks-

I have a John Deere 570A motorgrader that supposedly shares the same powershift transmission with the 4020, less the PTO.
Anyway, all forward gears are working properly, but reverse has quit; no backing up.
I was wondering if anybody had any ideas about that, and also if anybody can point me to any overhaul information.
Thanks much.

 

[K5lwq]

I would look closely at the linkage. I have no experience with a 570A.

The 4020 is my all time favorite tractor but the one I ran did not have the power shift transmission but hopefully someone else will have some good thoughts. Good luck!

 

[Swamp Monster 33]

I would look closely at the linkage. I have no experience with a 570A.

The 4020 is my all time favorite tractor but the one I ran did not have the power shift transmission but hopefully someone else will have some good thoughts. Good luck!

Thanks. The linkage is the first thing on my list. Much appreciated.

 

[Tx Jim]

Welcome to TBN
I agree on checking shift linkage & possible shift valve on lower RH side of clutch housing. 1-2-3-4 F & R utilize same trans components. My 1st guess is direction control cable failure which controls F/R in shift valve.

 

[Swamp Monster 33]

Thanks TX Jim- That's going to be first on my list today. Thanks again.

 

[Tx Jim]

You're welcome.

 

[Swamp Monster 33]

Tx Jim- Well; I carefully checked the Forward/Reverse linkage. I found a worn clevis that had a little play in it and hoped that it was the problem. Nope. Disconnected the Linkage at the trans and physically moved it into the reverse position. Nope again. Ran pressures on the the trans: got 150 psi in forward but only 50 in reverse. With the drive wheels raised and the trans in reverse the wheels actually move in reverse. Wheels on the ground, they try to move, but no.

 

[unimog_jason]

I can't speak to your specific transmission, but I have a 410 backhoe that probably uses a similar transmission design.

A known issue with the 410 transmission is o-ring failure on the clutch packs. If you're seeing 130-160 psi on the supply side, your o-rings are ok. If you're seeing less then 100 psi, your o-rings are shot and your clutch packs are slipping.

In the 410, the forward clutch packs are accessible from the front of the reverser, so you just have to pull the engine. The reverse pack are in the back and you have to pull the entire unit to get access to them. Might be the same deal with your transmission.

 

[Swamp Monster 33]

Thanks. Much appreciated.

 

[ovrszd]

Welcome to TBN!!!

If you don't get definitive answers here, try this website. A LOT of knowledge and experience there. Good luck!!!

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