450C only goes Forward

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Kodiman
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Joined: Sun Jul 11, 2021 4:00 pm

450C only goes Forward

Post by Kodiman » Mon Jul 12, 2021 6:28 pm

When I mean it only goes forward, I mean there’s no Neutral or Reverse at all. Fire it up and it just starts going forward. I can stop it with the clutch. It’s a late 70’s 450C. I thought there was a neutral safety on these machines? Anyways, I’ve checked the obvious, linkage, clutch adjustment (free play was way too much) changed the fluids, filters, etc. I did find a chunk of metal in the filter on the side of the transmission, part of a flat ring. Once I figure out how to post photos I’ll share. This machine is out at a remote Cabin which makes it tough to work on logistically. I’m hoping someone with more knowledge than myself could help point me in the right direction. I do have the manual to reference. I fear the next step is tearing into the transmission. Thanks

B Town
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Re: 450C only goes Forward

Post by B Town » Mon Jul 12, 2021 7:10 pm

Hello Sir,

Yes, the 450C did have a neutral safety switch as original equipment. It is a electric contact point, when the machine was in neutral, the circuit would be closed and allow the push button to send electricity to the starter motor. Once running the neutral safety switch had no function that I am aware of. This switch is one the left side, under the left floor board, about 3/4 the way back on the transmission. There is a mechanic gate that the operator must fill down to lock the HLR handle into the neutral position.

How much was you clutch pedal end play? The recommended 3 3/4”??

From you description it sounds like the clutch pack for the forward range is locked up. And likely a tear down.

Hope this helps, Bruce
Last edited by B Town on Mon Jul 12, 2021 7:30 pm, edited 2 times in total.

Kodiman
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Re: 450C only goes Forward

Post by Kodiman » Mon Jul 12, 2021 7:23 pm

Thanks Bruce. The free play in the clutch pedal was at least 4.5”. Now it’s at 3.75”

This machine ran great, right up until it didn’t. Haha. It gave very few clues, if any, before it broke.

Kodiman
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Re: 450C only goes Forward

Post by Kodiman » Mon Jul 19, 2021 4:16 pm

Question about the range linkage on my machine. I plan on pulling the top off my transmission next time I’m out at the cabin. I’ve followed the linkage to where it goes into the transmission and everything seems to be moving correctly. Question is, Is there a roll pin or some other mechanism just inside the tranny that could have broke and just not moving the internal selector? Broke while I was in Forward and that’s why it’s stuck in Forward? Thanks

Jim B
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Re: 450C only goes Forward

Post by Jim B » Mon Jul 19, 2021 5:14 pm

The HLR is hydraulic. There is linkage inside that works the valve. So linkage, or the valve itself, could have a problem. It could be related to the piece of metal you found. You say you have the manual for reference. Is it the technical manual, TM 1102? It should have info on linkage function, adjustment, and some pictures of the valve and linkage.

As Bruce said, the neutral start switch on the side of the transmission, works on the linkage going to the valve. If the linkage is complete from the lever to the shaft going into the side of the transmission it would seem it should still require the the lever to be in the neutral gate for the starter to work. If the problem is a stuck valve the lever might have to be in neutral to start, but the range valve isn't in neutral, the machine will move. So it is working if you have to have the lever in the neutral gate to engage the starter. The switch only looks at external linkage position, not the valve in side the HLR. So if the lever has to be in neutral for the starter to work and it starts traveling as soon as the engine starts, I would say the problem is the internal linkage or valve.

If you don't have a parts catalog you might want to print off the related pages from the on line parts catalog. You don't say if you have a dozer or loader so I'm guessing dozer. Here is a link to that parts catalog PC1 420 (the power train is the same in dozers and loaders, but the loader catalog is PC 1443). https://partscatalog.deere.com/jdrc/nav ... ment/67823

Kodiman
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Re: 450C only goes Forward

Post by Kodiman » Mon Jul 19, 2021 11:07 pm

Jim B, Yes it is a Dozer. Sorry about that. I have the TM-1102 manual. I can’t seem to find the blow up diagram that shows what the linkage does once it enters the transmission. It’s hard not having the Dozer here at home to look at. I’m just trying to get a game plan for next time I’m out at the cabin. I need to make sure I’m not over looking something that can be fixed without pulling the engine. That would be quite the project as the Dozer is in a remote location that isn’t road accessible. Thank you for the parts link.

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