2640 Has No Forward Or Reverse

[M Carp]

I was pushing brush into a pile in a hollow. I moved the reverser to reverse and nothing happened. Failure was immediate. Was in 1st gear. No unusual noise, vibration, etc. Nose of tractor was down on a fairly steep incline (not dangerously steep). I had to use my 'G' to pull it to level ground. Trans oil level was good.

It's a '79 model with reverser. About 7800 hrs on working tach. Two shift levers. Has a 148 loader. Hydraulics work as always and 3pt with 8' blade raise normally. I can only engage PTO with clutch depressed. Clutch seems the same as always. I can move both shift levers to any position without using the clutch. There is a very slight grinding at first with the left lever but just for a moment. The reverser makes no difference in either position.

I was just wondering if any of you have experienced this problem and where I should start looking. I have not removed the transmission covers yet.

Thanks

 

[Tx Jim]

1st thing I suggest to check is the reverser linkage. A groove or roll pin on RH at reverser control valve linkage has a long history of breaking or falling out of linkage. Next is to check reverser hyd pressure which should be 155-165 psi.

 

[M Carp]

Thanks Tx for the reply. But I was thinking about your suggestion on that pin. Even if the pin was missing wouldn't the valve itself still be either reverse or forward.

Could pressure to the valve fail that quickly, like immediately?
I'm going to have to come up with fittings and a pressure gauge though for checking that line pressure. I do have the JD Tech manual for the 2640.

Again, thanks for replying!

 

[Tx Jim]

Hyd pressure will be at valve but pin AWOL from linkage won't allow operator to shift from fed to rev or vice-verse

 

[Cliff Nelson]

The pin in question is on the clutch pedal shaft which controls a dump valve when the clutch is depressed. I'm thinking with the pin gone it will not move the valve to apply pressure to the forward or reverse
clutches. Visibly inspect the pin and linkage to make sure it is intact. Follow clutch pedal shaft across to reverser valve on right side of clutch housing. Pin is close to valve housing end of shaft. Let us know what you find.

 

[Russ from MN]

Is it possible the reverser pump has lost it's prime, maybe the suction strainer is clogged because of the
incline? I worked on reversers in crawlers in the 70's, don't know if this is similar.

 

[M Carp]

Thanks Cliff and Russ for replying. Cooler today so I will be crawling under the tractor and checking Tx, Cliff and Russ suggestions.

This is my main battle tractor and am lost without it. In the 20 years I've owned it I've only had to replace the brakes and one injector.

 

[M Carp]

Well, the pin at the end of the clutch shaft was missing! A major tractor problem with such a simple fix. It would have taken me a long time to find that without you guy's helpful suggestions.

Thanks again for all your help!
Mike