New Holland TN75DA Power Shuttle Transmission Problems

[rodgerm140]

My TN75DA has been to the dealer as a result of Power Shuttle Problems, for no obvious reason when you engage the shuttle it will momentarily attempt to move forward or reverse and then appear to go into neutral. It does not throw any codes but the dealer has replaced the PCM, a diode, the seat switch and calibrated the PCM, it worked find after I got it back then today it was back to the same trick. I shut the tractor off for about an hour then went back out and started it up and it worked fine, sofar I have spent about $3000.00 on the problem which appears to not have been fixed. I will be calling the dealer in the morning but wondered if anybody else has had this problem? Thanks, Rodger

 

[RickB]

A faulty transmission pressure switch can cause all manner of symptoms and often not set a fault code.

 

[rodgerm140]

A faulty transmission pressure switch can cause all manner of symptoms and often not set a fault code.

Rick, Thank you for responding, I did not mention it but before it went to the dealer I replaced both of the transmission pressure switches but the problem continued. Any idea if the trans. temp. sensor would cause a complete loss of forward and reverse operation, I am going to attempt to do a resistance test on it when I get a chance. It is such a strange problem since one minute it works great then not at all and hour later it is fine again. I was hopeful that the new ECU was going to fix it but now the problem is back again. Regards, Rodger

 

[RickB]

A failed trans temp sender is uncommon. An intermittently failed one would be less common yet.

 

[rodgerm140]

Thanks for your comments on the temp. sensor. Drove it around today a few times and it seems to work like nothing had happened the other day. I guess I will continue to use it to see if the issue returns or it was some kind of fluke. Rodger

 

[elkhurst1]

Hello, I wanted to pass on an experience I had with my TN75da that I just got cured this past week...
A few months ago I tried jump starting another tractor that I thought had a bad battery with my TN75da. Turns out that the other tractor had a bad frame ground from the battery. After that I had nothing but trouble with the TN75 going to neutral from either forward or reverse. Like you, I had no ECM codes, but the Transmission light on mine would come on. When that happened I tested the battery and it was bad, so I replaced it. Afterwards, it (seemed) if the battery was at 100% the tractor would work just fine, but the moment you added any other load, the transmission would go to neutral. At that point I purchased a relay tester for about 50 bucks on Ebay. I tested every relay in the fuse box and they were all good. I also tested the relays in the right hand cab support. 3 out of the 4 were bad! I purchased new ones from NAPA and replaced them.....the tractor seems to be doing fine now.