Good afternoon, we have a 2012 d6t that has started to act up. The guys will switch into neutral while backing up, then when it coasts to a stop (similar to how you would check track tightness) then shift to forward when it's basically stopped. The dozer beats them to it by slamming to a stop. The park brake does not turn on, but it acts like it does. It seems to do it worse in 2nd gear reverse, but has started to do it in 1st gear as well... I'll try attached a video.
You can’t. It will need to be hosted somewhere else and linked. Post a Serial Number please. Also what Diagnostic Codes (if any) are Active.? Also I’m intrigued as to why an operator would want to flick the transmission into neutral when changing direction. Why not just hit the decelerator pedal and the brakes.?
Thanks for the quick reply Nige! THere are no disgnostic codes. serial number DTD00220,
The operators typically don't use brakes unless they are on steep grades. The cat does not typically lurch, especially when they shift from reverse-forward, or forward-reverse happens quickly. They noticed it and slowed things down to find out where it's happening. Could it be a wore out rocker switch, or do we need to calibrate the transmission?
You need to recharge the accumulator under the fuel tank to maintain brake pressure while shifting. The brakes pop on for a second because off the pressure drop when you shift. You should also do a brake calibration while your at it. I just had one doing the same thing and the main problem was the accumulator.
Thanks, we'll head out with a recharge kit tomorrow. Hopefully our software can handle the calibration.
250 psi is charge pressure with machine shut off. You will see the accumulator from behind the machine looking up under the rear of the fuel tank.
Thanks. Do you happen to know the fitting we need to connect to it?
The small one like a car tire valve stem.
Accumulator is #32 You'll only need a pressure gauge to test the precharge pressure but if you find that the pressure is low, or even completely discharged (which should set off alarm bells because it might be U/S), then you will need a nitrogen charging kit. The accumulator is not serviceable BTW.
Thanks. We do have a charging kit. I'll let you know how we make out!
The pressures were zero so we'll be swapping out that accumulator. Thanks everyone!
Not going to try charging it, at least to buy you some time.?
Yes, we did that
The tractor is 12 years old (it was manufactured in 2011 BTW) and I'd bet that's the first time the accumulator has ever been recharged. It is a piston-type accumulator that generally tend to be pretty reliable. You might just get lucky and a recharge fixes it, fingers crossed.
This problem had come up in a thread only a few months ago needing the same bit of a tune up, the Nitrogen cylinder should be checked at least every year by your Service Crew, the main benefit of the Gas Cylinder is to assist with transmission shifts at low engine speed, the earlier Series Tractors had a Mag Valve on the cooler line to prioritize extra oil feed at low engine speeds to help transmission clutch fill.