What fluid are you using in the transmission? This is more about oil viscosity than oil level since you said that is good. JD recommends low viscosity Hygard for GT's in colder climates.

 

I don’t know exactly what the previous owner had in there other than it’s pink. I figured it must be F type ATF.

 

the oil warms up with operation so I don't think viscosity will play such a huge role here... form moving normally to not-moving at all.

plus the OP said: "...I’ve noticed that while the tractor will go into reverse every time with no problem, when I try to go forward, the selector knob is stiff and at times doesn’t want to budge...."

It sounds like loose linkages. Maybe a setscrew or sheared key?... things get cold, shafts contract creating a bit more gap between a shaft and an actuator arm/cam, reductiong friction on a broken key-way decreases etc... and your movement control lever is not actuating the go/no-go actuator on the transmission.

 

Guess I’ll need to get in there and see what could be loose. But would any looseness be cause for the control lever to feel like it’s resisting when I push it forward? Similar to a shock absorber you can’t fully compress. I can force it forward but it bounces right back.

 

The only time I have felt that resistance on the hydro control was when the transmission was low on fluid. I still wouldn't rule out viscosity because you said temperature has something to do with it acting normal or not. That would indicate something with the fluid, but I agree with Wally2q that checking your linkages isn't a bad idea either!

 

This might be a reach, but is it possible that the hydro dampener is resisting in the forward direction? Dampener affected by the cold?

 

I appreciate all the answers on here.

So I went in and pulled the dampener off because I felt like I was fighting against something like a shock absorber or spring or something. The dampener seems to be fine, but I've never pulled a small one like this off a machine before, so I have no frame of reference. Maybe shouldn't be able to move it at all? It compresses and decompresses without an excessive amount of force.

What I realized when I had it apart, was that the resistance I feel when pushing the selector into the forward position comes from a big spring in there. The tendency (I'm assuming by design?) is for the spring to pull the selector back to the Neutral position. But maybe that's what the dampener is designed to counteract, and when both are working properly the selector moves up and down the speed range with little effort?

I also checked the fluid level again and it seemed a bit low, and added some (which is a pain in the neck, I've got more in my catch pan than I got in the tractor). The best I could tell the various linkages seem pretty tight, but again, maybe inexperience doesn't tell me enough how they are supposed to feel). At any rate, it's still cold, I still can't get it to go reliably into forward on the first try, but reverse is still reliable.

One thing I did notice once it's back together, is that when I do get it to go, I can adjust my speed faster or slower as needed -- even though it jumps off to a fast start when it goes with a spin of the chained tires. But I also noticed that when I get it back to the Neutral position, it still tries to go forward. and I've got to nudge it into reverse to actually stop.

 

the damper may be half full of water... expansion (stretching) during REV actuation is easy... but compression of the dampener during FWD actuation - into a block of ice would cause a bit of resistance.....

 

Colder temperatures will highlight issues that don't even show up at warmer temperatures due to shrinking of the steel parts. The damper would be a good starting point, followed by inspecting the rest of the linkages for tolerances that have changed due to wear.

As long as you are inspecting, check the parking brake. It can cause similar issues.

The ATF works fine at sub zero temperatures. Like any other hydraulic fluid, it's just a bit sluggish until it warms up a bit.

 

The ATF works fine at sub zero temperatures. Like any other hydraulic fluid, it's just a bit sluggish until it warms up a bit.

plus, if it was fluid related, you would not see a difference in behavior between FWD and REV.

 

Well hydro creep is something that is adjustable. This small fork should be able to be spun in and out to adjust it, it doesn't take much adjustment to make a difference so one/half turn at a time and test.

 

something is binding in your linkages at low temp....
may want to get someone to help move the lever while you are under the tractor checking it out with a flashlight....

 

So you be been playing with the dampener and I’ve found that something is stopping the dampener from going into the decompressed state when I try to go into drive. With a pry bar I can exert some force to get the dampener to open up and the drive function works flawlessly, changing to multiple speed positions, until it gets back to the neutral position. Then it’s the same thing over again. But with the dampener off, there doesn’t seem to be any trouble decompressing by hand. Can’t figure out what’s preventing it when it’s on the tractor. I had a video, but I can’t seem to kid it. Here are two photos. One of it compressed and one decompressed.

You’re right in the money! Got under there and moved the lever while prying a bit with a key bar and heard something clicking behind me. Not sure what this is called. But it comes out of a little dip and overcomes the tension in a spring to go into reverse easily. But not forward.

 

View attachment 2484293

 

 

Well, problem is solved. There’s a little spacer on that 1/2 inch bolt that rolls into the indentation. It was squared off in several places so it looked like an octagon. I flipped it around for now until I can get a new spacer in there. The previous owner must have flipped it around himself, because the other end was slightly squared in just one spot. And there’s a thin bit of metal in the middle that’s fully round all the way around.
Thanks everyone for all the suggestions!!