John Deere 110 TLB surging

[Jbrink64]

OK, I have a JD 110 TLB with a surging transmision. The "open book" light comes on momentarily when the key is turned on. It is not flashing any codes. The problem worsens as the machine warms up. The voltage to the HST sollenoids varies in rythem to the surging. Unplugging the engine speed sensor causes the light to flash a code for the sensor, and the transmission stops surging.

Anyone have a fix for this? Would recalibrating the trans help, and what is the procedure to do it?

Thanks.

[AKfish]

Well... it sounds like you've already isolated the problem! The engine speed sensor. Unplugged - code flashing - surging stops.

Replace the speed sensor.

I'll take a look at my Technical Repair Manual and see what information is available there. But, in the meantime...

How expensive is it to replace the speed sensor?

AKfish

[Jbrink64]

I replaced the speed sensor, that didn't help.

[jenkinsph]

Does the engine rpms' surge while sitting still or does the tractor movement surge at a set rpm?

[Jbrink64]

The engine will stay at a set speed. The ECU will rapidly change the voltage to the HST solenoids, causing the surging.

[jenkinsph]

I would have the dealer plug in to it and perform a diagnostics on the unit. When I first got my 4520 home the computer wouldn't allow the tractor to move. The dealer came out and reprogrammed it and no further problems in the last two years.

[camperfriend]

Did you ever find the problem with the surging? I am having the same problem. Any help would be great.

Britt

[Jbrink64]

Did you ever find the problem with the surging? I am having the same problem. Any help would be great.

Britt

The engine and ground speed sensors both failed, then the trans needed recalibration.