Have a 621B loader with the auto shift transmission. Had it about 4 years now and ever since we got it when you shift forward or reverse sometimes it would never engage. You would have to put it back in neutral a few times and eventually it would engage in gear. It would always instantly go into forward or reverse when it did work. However, now when I put it in forward you can hear it shift 3 separate times slowly moving a little more until it completely engages. Reverse you can hear it shift 2 times before it moves. It shifts fine between all gears once it gets going, it's just the initial shift into forward and reverse that it's not quite right. I'm leaning towards it being the shifter itself, but don't want to spend 800 dollars if there is something else it might be. Any way to test the shifter? Thanks for any insight you can give.
Modulation spool sticking gasket coming apart? These machine were famous for bad valve gaskets as well, allowing oil to leak past or pieces of gasket sticking spools. Use a couple of dowels remove 2 valve bolts, thread dowels in now remove valve. Pressure checks may help you narrow down the problem. Modulation comes into play when shifting from neutral to forward or reverse.
Okay, thanks. I ran it again this morning and when I have the declutch switch on and press in my left pedal and switch from forward to reverse or vise versa it works fine. It switches instantly between them if I hold the pedal in and let it go in in reverse or forward, but if I don't press it in and switch frome forward to neutral to reverse it doesn't do it instantly. So, would that confirm what you said?
This sounds like an issue on brake switch to me. When you "hear" it shift, guess, these are the solenoids being energized. The declutch switch should allow KV and KR being cut out with brake pressure around 30% and more. Your system seems to work the other way round. (Sometimes) no shift without declutch.
Can you explain a little more? Since it is cutting out when pressed, wouldn't that mean it's working correctly?What are KV and KR? And I should clarify, it does always shift without pedal pressed, but it's not instant like with pedal. I'm assuming your talking about the switch on the left pedal, right?
Which type of transmission is fitted in the 621B. 4WG150 or 4WG180? As I understood, t/m shifts w/ left brake pedal depressed? Both t/m need two clutches for moving. 1st:KV (forward) and K1, 2nd: KV and K2, 3rd: KV+K3, 4th: K4+K3, KR to move reverse (no 4th). Declutch takes away pressure (24V of solenoid) on KV to allow full performance on PTO (hydro pumps). Is there a brake pedal fitted on right side of steering column? This would not allow declutch. With the info on t/m type I could get you an operators manual in a conversation with some good info about hydraulics and electrics (shifter+ t/m)
It's the 4WG150. There is a brake pedal on the right side of the steering column.