Cat 955K 85J - no reverse

[Iron Dinosaur]

Machine has existing problems with right side drive being weak or out, but it always engaged into gear and would move in forward and reverse, mostly under the power of the left side. Months ago, I adjusted the foot pedals according to the service manual, they were way out of spec. Since the pedal work, the tractor will go forward but not reverse. Could that be as simple as the brake band(s) are stuck? I did make some mistakes initially with the pedal settings but eventually got it right, could have cranked too much on the brake setting bolt, but I'm not sure. Nothing else significant has been changed. The machine does sit for several months at a time without being touched, also not sure if that adversely affects anything.

 

[Nige]

Before you go messing with the brake adjustment again, a question. When was the last time you changed the powertrain oil & filter, and removed/inspected/cleaned the suction screen #17 in the illustration.? If there is a problem with the reverse clutch starting to give up the ghost the first place you ought to find burned friction material, and possibility metal particles, is in that screen. It would probably be worth your while to eliminate the possibility of a failing clutch before going further.

 

[Iron Dinosaur]

Nige,

I have never checked those things at all. It took a little searching but I found your illustration in my copy of the service manual PDF. Will need to look into this and see what the part number is on the filter. May have follow-up questions for you after I get to poke around on the machine. Do you know the correct specification for that powertrain oil? Quantity? I have not yet attempted to change any fluids. I have a 5-Gal. bucket of Cat TO-4 equivalent oil, but my understanding is that is meant ONLY for the final drives.

Thank you very much for addressing my post!

 

[Nige]

Will need to look into this and see what the part number is on the filter.

For clarification. The filter (a replaceable element) is shown as #23 in the LH part of the housing in the illustration.
The screen (washable in kerosene or similar) is #17 in the RH part of the housing. The screen also has a Tube #13 with 4 magnets #14 inside it. If there is metal debris it will be on the magnets, anything non-metallic will be clogged in the screen.

I would suggest that you leave the filter side of the housing for now and just go into the screen side.
If you go into the screen housing I would also suggest to post photos of whatever material you find.

 

[Nige]

have not yet attempted to change any fluids. I have a 5-Gal. bucket of Cat TO-4 equivalent oil, but my understanding is that is meant ONLY for the final drives.

TO-4 oil is also used in the transmission/torque converter circuit. What viscosity oil is in the bucket you have already.?

 

[Iron Dinosaur]

 

[Iron Dinosaur]

It looks like tiny fines to me on the magnets, but will defer to expert opinion. The screen looked almost brand new - nothing on it at all. Not sure how important this is, but the screen was installed upside down. I only know this because the rim of it is stamped with "this side out".

 

[Iron Dinosaur]

The oil I have is SAE 30W.

 

[Dave Neubert]

955s are bad to wear the bushing where the shift lever goes into the transmission housing pull the floor boards and manually shift the fwd. rev. lever. do it where it goes into the housing

 

[Nige]

You definitely haven’t had a clutch failure. Go with Dave’s suggestion as a next step.

 

[Iron Dinosaur]

You are definitely on to something, the FWD/REV lever into the transmission housing is stuck, I can't move it.

 

[Dave Neubert]

are you trying to move it with the loader not running, because it has a netural safety that will keep it from moving. if not then you need to pull the top cover and maybe the valve body out and free up spool

 

[AllDodge]

My 955 was hard to go into reverse when I first got it. Prior owner showed me that the pivot link on the rear of the trans was dry and would barely move. The pivot doesn't have a grease fitting, so removed, greased and not it works fine.

I have a thread which shows the pivot, will see if I can find it

 

[Iron Dinosaur]

Is the neutral safety the switch or contact behind the FWD/REV change linkage? I see the wire to that is broken or disconnected on one end, wasn't sure what it did. Anyway, the machine is stuck, on flat ground, not trying to roll it not running. I will have to see about getting to and opening the top cover on the transmission, it's a little tricky to reach, I guess the foot pedals will have to go to get in there.

 

[AllDodge]

The neutral safety would not keep it from going into gear, just keep it from cranking if it was connected and did work.

I found my thread but the pics are messed up, so no help. It's raining but if it stops might be able to get a pic.

 

[AllDodge]

The stick is pointing to the pivot

 

[Dave Neubert]

The neutral safety would not keep it from going into gear, just keep it from cranking if it was connected and did work.

I found my thread but the pics are messed up, so no help. It's raining but if it stops might be able to get a pic.

not talking about a switch it is a valve in the control valve that moves the shifter to neutral when not running you can over ride the spring but makes it hard to pull and will go to neutral when you let it go

 

[Dave Neubert]

Is the neutral safety the switch or contact behind the FWD/REV change linkage? I see the wire to that is broken or disconnected on one end, wasn't sure what it did. Anyway, the machine is stuck, on flat ground, not trying to roll it not running. I will have to see about getting to and opening the top cover on the transmission, it's a little tricky to reach, I guess the foot pedals will have to go to get in there.

No it is not a switch it is a spring loaded valve in the control valve

 

[Dave Neubert]

Dis connect linkage from transmission and make sure it is all free

 

[Iron Dinosaur]

You were right about the bushings on the FWD/REV shift linkage, completely frozen. The original bushings were steel and corroded. I put the replacement bushings in and it shifts perfectly.