Ford 420 Reverse Issue

RedBarnFarm · Sep 3, 2021

Hoping to get some guidance on a Ford 420 with a torque convertor transmission. When you first start running the tractor everything seems to work fine, shift to forward, neutral and reverse with the selector fine and everything works as it should.
When the engine heats up forward and neutral are fine but when you move the selector to reverse it just sits there. If you rev up the engine after about 20 seconds or so it will suddenly jump in to reverse and go.

I took it to a mechanic (who had it for 6 months) and he split the tractor and went through some internal seals and the transmission and put it back together and said it was fixed. I picked the tractor up and ran it for 5 hours moving hay and then it went right back to doing what I described. I took it back to the mechanic (he kept it for 3 months without working on it) so I just went back and picked it up and I am determined to just fix it myself.

So - my thought is the hydraulic valve that the forward neutral reverse shifter operates is the problem. Does anyone have any experience with this repair? Totally flying blind but looks like you have to remove the diesel tank, steering column etc to access the plate where that valve is. Thoughts on if I am on the right track with the diagnosis or repair? Thanks in advance.

Check Break · Sep 3, 2021

(quoted from post at 15:45:36 09/03/21) Hoping to get some guidance on a Ford 420 with a torque convertor transmission. When you first start running the tractor everything seems to work fine, shift to forward, neutral and reverse with the selector fine and everything works as it should.
When the engine heats up forward and neutral are fine but when you move the selector to reverse it just sits there. If you rev up the engine after about 20 seconds or so it will suddenly jump in to reverse and go.

I took it to a mechanic (who had it for 6 months) and he split the tractor and went through some internal seals and the transmission and put it back together and said it was fixed. I picked the tractor up and ran it for 5 hours moving hay and then it went right back to doing what I described. I took it back to the mechanic (he kept it for 3 months without working on it) so I just went back and picked it up and I am determined to just fix it myself.

So - my thought is the hydraulic valve that the forward neutral reverse shifter operates is the problem. Does anyone have any experience with this repair? Totally flying blind but looks like you have to remove the diesel tank, steering column etc to access the plate where that valve is. Thoughts on if I am on the right track with the diagnosis or repair? Thanks in advance.

There's two valve bodies. One in the oil divider above the pump and the other on top of the oil divider. The one on top is directly below the steering column. You can pull the upper body apart and look for a broken spring or stuck valve but you should check the linkage on the lower valve first. This can be accessed from the bottom (bellhousing plate) and/or from the top by removing the steering box. It helps if you have small hands and some Houdini dna. There is a pin that attaches the bellcrank to the F/R valve. That pin wears and creates the symptom you describe. F ok, problem with R, or R ok, problem with F. If that pin is not worn, then you can check the upper valve body. Post back with what you find and we can go from there.

RedBarnFarm · Sep 3, 2021

So looking at the diagram the valve I assume we are looking at is #25? Is the pin you mentioned shown in this particular diagram?

Check Break · Sep 3, 2021

(quoted from post at 19:52:39 09/03/21) So looking at the diagram the valve I assume we are looking at is #25? Is the pin you mentioned shown in this particular diagram?

No. 25 is the valve. When you see it looking down from the top or up from the bottom, the left side of the valve will be protruding through No. 26. The bellcrank is pinned to the horizontal linkage in the bellhousing.

The pin is not shown in your picture. Check out Transmission Page 07AD1 on FNH parts. It is part No. 23 and 22. Horizontal linkage is part No. 19. Bellcrank is No. 20. The pin and cotter pin can be sourced locally.

RedBarnFarm · Sep 4, 2021

You weren't kidding about the small houdini hands. I was able to get the cotter pin out but not the pin itself, luckily my son was able to reach in further than I could. Pin looked good. I guess now I need to study how to remove all the dash, fuel tank, and steering. Next likely spot is a broken spring maybe in that other assembly?

Everything was working good again this morning until it heated up then back to delayed engagement on the reverse. Seems like when the oil gets hot/thin it must start leaking by somewhere or something I guess.

Check Break · Sep 4, 2021

(quoted from post at 09:25:46 09/04/21) You weren't kidding about the small houdini hands. I was able to get the cotter pin out but not the pin itself, luckily my son was able to reach in further than I could. Pin looked good. I guess now I need to study how to remove all the dash, fuel tank, and steering. Next likely spot is a broken spring maybe in that other assembly?

Everything was working good again this morning until it heated up then back to delayed engagement on the reverse. Seems like when the oil gets hot/thin it must start leaking by somewhere or something I guess.

Now is the time to decide whether to split it. If you split it, the steering gear, fuel tank and sheet metal stays in place. Everything is accessible with a split. If you pull the steering gear, leave the tank and sheet metal attached. Pull it as one piece. Just disconnect the tach cable, wiring harness, kill cable, ect.

RedBarnFarm · Sep 4, 2021

I'll look at pulling the steering gear all together then. I don't really have the necessary shop or tools for splitting it I don't think. If I can pull the steering/tank and all off in one piece that doesn't sound like a bad idea. I figured I would have to take all of that apart to get to that plate.

Check Break · Sep 4, 2021

(quoted from post at 10:30:36 09/04/21) I'll look at pulling the steering gear all together then. I don't really have the necessary shop or tools for splitting it I don't think. If I can pull the steering/tank and all off in one piece that doesn't sound like a bad idea. I figured I would have to take all of that apart to get to that plate.

If you have a floor jack, jack stands, hand tools, bottle jack and wood blocks you're good to go. The rest you can make.

RedBarnFarm · Sep 4, 2021

(quoted from post at 15:34:26 09/04/21)

(quoted from post at 10:30:36 09/04/21) I'll look at pulling the steering gear all together then. I don't really have the necessary shop or tools for splitting it I don't think. If I can pull the steering/tank and all off in one piece that doesn't sound like a bad idea. I figured I would have to take all of that apart to get to that plate.

Click to expand...

If you have a floor jack, jack stands, hand tools, bottle jack and wood blocks you're good to go. The rest you can make.

I would have to disconnect the loader as well I guess. Given the 2 options which way do you think would be easier for an inexperienced person to try? I've made some fairly simple repairs on a few of my tractors but I have never split one.

Check Break · Sep 4, 2021

I would have to disconnect the loader as well I guess. Given the 2 options which way do you think would be easier for an inexperienced person to try? I've made some fairly simple repairs on a few of my tractors but I have never split one.

You leave the loader on the tractor. The loader frame unbolts from the front bolster and the loader is blocked between the front of the lift cylinders and the rod end. I advise first timers to remove the bucket first as it removes a lot of weight above your head and makes the tractor safer to work on.

It might not be a bad idea to remove the steering gear first as it will open up the tractor and make it easier for you to understand the split. If you empty the fuel tank first and you have some help, the steering gear comes off pretty easy.

Check Break · Sep 5, 2021

I would have to disconnect the loader as well I guess.

I was looking for some online pictures for you that shows a tractor split and realized your loader bolts to the hardnose, not the front bolster, but the process is still the same.

Still looking for a "split" video, but here's a thread that will give you some direction once you're in. You have the later blocker valve, the one on top of the oil distributor, so don't get confused by the earlier valve.

https://www.heavyequipmentforums.com/threads/ford-555-backhoe-early-eighties-shuttle-removal.72442/

RedBarnFarm · Sep 5, 2021

(quoted from post at 08:06:27 09/05/21)

I would have to disconnect the loader as well I guess.

Click to expand...

I was looking for some online pictures for you that shows a tractor split and realized your loader bolts to the hardnose, not the front bolster, but the process is still the same.

Still looking for a "split" video, but here's a thread that will give you some direction once you're in. You have the later blocker valve, the one on top of the oil distributor, so don't get confused by the earlier valve.

https://www.heavyequipmentforums.com/threads/ford-555-backhoe-early-eighties-shuttle-removal.72442/

I really appreciate that! This should be helpful. Working on clearing a spot in the shed to fit it in to start disconnecting things.

Ford 420 Reverse Issue

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