Hi iam the only one in UAE using champion graders from a few years. They are doing great job for me except some times i got little spare parts and other problems. I found this forum can be a great help for me so i will appreciate your help alot. Lately my champion 740A 1995 model is having some transmission problem. If is only going forward and is not moving when we engage it in reverse gear. instead when we release the clutch it give some annoying sound like something is stuck and is still revolving. A local mechanic open the transmission and found nothing wrong inside. So he just clean everything make a small service and install it again. It worked for one time but it engage from 1st grear to 4th gear directly. We open the electric control pannel and it start making the same problem again. I have no idea is this a mechanical problem or only an electric one. Kindly help!
So this is a series III grader then? Does the gear indicator in the controller still work? Does it go from 1 directly to 4 on the indicator? Or is it 3 and 3 don't work so you keep moving the lever until you're in 4? All other gears work normal? If the others work normal, I guess I would be suspicious of the controller (JUST GUESSING THOUGH- I haven't experienced the same issue myself). With the reverse gears not working, I wonder if that is a faulty coil on the solenoid? The coils just slide off. The spool it goes over could be over-torqued too. Or possibly wiring harness worn through or connector. I don't have a manual right handy, but basically those 8400 transmissions have 4 clutches. One for even number gears, for instance engaged on 2,4,6,8 and not engaged for 1,3,5,7. There'll be another clutch for groups 3,4 and 7,8 and not engaged for 1,2 and 5,6 (that's the only one I remember, it's "C" clutch Then one for 5,6,7,8 and disengaged for 1,2,3,4 and then last clutch would be reverse. So it seems odd to me that you would lose 2 and 3, that would suggest an issue with 2 separate clutches (or solenoids) and then another one again losing reverse. In the controller there are some magnets. I think they move a bit when you are upshifting/ downshifting and engaging forward and reverse. We have had a bit of trouble with those controllers. I'm not sure if it's because of dust or metal filings, or maybe even wear, but we've had where you'd have to move the lever several times before it would upshift in certain circumstances (always when crossing a highway when a car is coming!!!). The mechanic my boss used would clean things up a bit and that would help but the problem would usually only be resolved temporarily. Hope this helps a little, but sorry I couldn't be of more assistance.