Clark 666B skidder transmission wont shift into reverse 2420

VelmerD · July 26, 2018, 12:58:22 PM

Well the skidder was working perfect then after backing up to the pile to drop my drag, I put the skidder in forward and nothing it acted like it was in neutral. I then checked all the shifting linkages didn't see any problems so I put it in forward and gave it some throttle it then jumped into forward, so I drove forward and when I let off the throttle it acted like the brakes where on, Then it wouldn't go into reverse so I changed the tranny filter and it worked great again except I notice it slipping in reverse a couple times only, so a couple days later it did the same thing backed my drag to the pile dropped it winched in the cable put in forward and nothing. So I pulled the main control valve off took it apart new seals didn't see anything out of the ordinary, I also removed the pressure regulator valve off the torque converter replaced springs and seals didn't change anything other than it goes into forward and not reverse now. I also changed the fluid and cleaned the sump screen which was clean except for a few metal shavings. the skidder goes forward down the trail in high and low no problems but will not go into reverse if I pull the cable out and put it into reverse and tap the winch to pull the cable in the trany makes a fluttering sound like the clutch pack is trying to ingage. the trany is a 2420 shuttle shift any info would be greatly appreciated thanks.

mike_belben · July 26, 2018, 03:26:43 PM

Does the control valve have two spools, one for fwd/rev and one for which speed?

VelmerD · July 28, 2018, 09:59:50 AM

the control valve has 2 one is for forward neutral and reverse the other is for high and low

mike_belben · July 28, 2018, 04:45:36 PM

Disconnnect all linkages and see if you can manually move the spool into the right position for each gear to function or not.

Its a fork in the road. If no, problem inside valve or trans. If yes, problem outside trans, in the linkages.

VelmerD · July 29, 2018, 11:24:47 AM

i had the valve apart and didn't see anything out of the ordinary and I did remove linkage and moved the spools without the linkage attached so your thinking internal in the transmission? Not looking forward to removing the tranny. Thanks for your input

mike_belben · July 30, 2018, 12:37:30 AM

That stinks.

Before you tear down try to find a shop manual with pressure specs for each port. These things are usually covered with pipe plugs, youll want to know what pressures you got where in order to.narrow down on the problem. Beyond that im probably not much help on this one.

VelmerD · July 30, 2018, 08:16:11 AM

Thanks for your help, From what I found your suppose to take the pressure check from the trany filter housing but It dosnt have a plug or port to plug in the pressure gauge :embarassed: so I don't know what or where else I could plug it in.

mike_belben · July 30, 2018, 09:05:42 AM

Keep scraping the crud, youll find something. My komatsu has pipe plugs on all the valve blocks that control it.

VelmerD · August 11, 2018, 09:31:52 AM

removed trany opened it up and found that all the clutch disks were broke in pieces in the reverse clutch drum. Happy to finally have figured out the problem but having problem finding parts for it, if anyone knows where to find parts for Clark transmission please chime in thanks

mike_belben · August 11, 2018, 03:11:45 PM

Call and ask trevor at betterbilt transmission on rocust street in springfield mass if he knows anyone. He is a roadranger shop but has been in the heavy driveline rebuilding business like 50 yrs. Knows everyone.

Others id try..
Delks forestry junkyard in jamestown TN.
Camerota truck parts in enfield CT
The truck rebuilders on rt 13 in lunenburg MA. Cant remember name.
Mikey @ RCS diesel in ludlow mass. They used to rebuild skidders and have an entire wall of parts vendor books. May have a clark parts source.

VelmerD · August 12, 2018, 07:17:34 AM

Thanks Mike i will give these places a try, will let you know if I have any luck.

mike_belben · August 12, 2018, 09:36:20 AM

Coincidentally i came across an ad last night for a guy specializing in heavy equipment transmission rebuilds. Said he had his own parts suppliers, was located in Kentucky.

(606) 312-2065

VelmerD · August 12, 2018, 12:44:13 PM

Interesting thanks again Mike

celliott · August 12, 2018, 05:57:37 PM

Pete's equipment in Morrisville VT used to be a Clark dealer and still has very knowledgeable guys for Clark parts and can get most stuff. They helped me get the right seal for my 666c and figure out it's not a D like it's painted but a C.

866-237-3189
802-888-5138