662 skidder

Sask logger · February 05, 2021, 08:58:50 PM

I just got a 662 clark skidder took it to the bush to try it out first drag I stopped backed up when I put it in forward it does nothing . Does anybody have any idea of what the problem could be oil is up in trans .

mike_belben · February 06, 2021, 09:13:41 AM

Shifter cables/links are still connected and the detents still feel normal? No change in engine sound, no bangs or terrible sounds while running?

Will it continue to operate in reverse or are both lost?

If youre sure its got fluid and is on flat enough ground to suck it up the sump tube, then ya need to be sure the trans is recieving the shift input.

Pull whatever tin necessary to see the spools on the control valve section of the trans and see if theyre moving the full range. Use a tool if necessary to get in there and manually stroke them in and out. Rev it up and see if it suddenly grabs while moving these spools.

You didnt spring a big leak in the cooler circuit right? Does it constantly drool out trans oil into the belly?

Sask logger · February 07, 2021, 12:01:02 PM

There's a control valve to the left of seat linkage to it is good then hoses from there to transmission all good no leaks .there were no bangs or anything weird when it quite , just backed up and then it would not go ahead . But it was a little laggy go into forward compared to reverse . And yes reverse is still 100% . No oil in belly .

Sask logger · February 07, 2021, 12:04:02 PM

Haven't checked the rad for oil but the transmission was still on full when I checked it .

Sask logger · February 07, 2021, 12:07:49 PM

Does anybody know were a guy could get a service manual for 662 ?

mike_belben · February 07, 2021, 12:42:37 PM

Sounds like my dozer except when cold i will lose reverse until it has driven forward a minute or two and circulated some oil inside. It has a mind of its own as to when itll finally "grab" if you can go forward first. When it does the reverse is fully there and strong as can be so we can reason mine is an issue in controlling the valves that block flow to tank and direct it fully to the piston that clamps the reverse planetary. (Ive been inside my sump and its very clean but i never found any issue inside the control vales either and have learned how to manage it until it fully breaks and has to come out) i can feel when mine is about to have reverse come back. Its like a really really slow releasing of a clutch pedal, just tickling the flywheel a bit and then woomp its off to the races with full power in all gears and directions.

Get in the seat, let it warm up all the way, check all your fluids again, and try any stupid thing you can to get your machine to engage forward. With no bang and not dying under severe duty i dont think yours suggests a catastophic internal conponent faliure. I think it suggest the accumulated leakage of 40yrs of spool shuttling, combined with winter temps makes clearances worse and finally crossing the threshold where pump pressure doesnt shuttle some spring loaded piston or check ball or other doodad in the control section. Fluid acting against a piston face with a spring in opposition is how valvebodies are built and they have that gray area where they balance instead of fully shift. Like a light switch sitting half way. Its neither on nor off. Ive seen this in many marginally dead old powershift machines in my scrap life.

Rev it up and down while shifting, hold it wide open, toggle through all the speeds in all directions, raise and lower the blade and steer it lock to lock to get the fluid in the trans sloshed around and watch the rubber for signs that you are getting warmer. If it engages with a sudden jolt to life and then works great, it kinda supports what im saying. Get it to a good place for teardown and make sure you dont block it in front or rear. You may need to drive in reverse circles a while before forward will work reliably.