I think the serial number is 7U30279 but I for sure have the parts on OM: s first picture. I guess I must check the serial number again!? Anyhow, I have a scrap HT-4 and if it has the newer parts, can I move them to my tractor or is the mentioned adapters required?

Most important I guess is that the operator is aware that it is a classic equipment that is not as new. I will make this cleat to him!

MATS

The shift gate change occured at s/n 7U20691 and yes the parts will interchange.

I am trying to remove the shift assembly from my D4, but the swing lock will not fit through the circular opening. Am I missing something very basic?

Thanks,

Glebis

We recently purchased a Cat D4 7U. This was a running operating machine and we feel it was fairly priced. We have a d4 7u that has the transmission stuck good. we were pushing brush on a fire and it starting grinding (like gears) then stopped. we removed the shift lever and the center trans slide will not move, we were prying with a 5' bar, and cant budge it. Any suggestions would be greatly be appreciated... the machine will not roll unless steering clutches are pulled. Also while messing with trans, we plan to drain the trans fluid and replace. Is this gear oil, engine oil or hyd oil?

Think you’re in for a major transmission disassembly. Once you have the top cover off the clutch/transmission/bevel gear case, you should be able to see better what you’re dealing with. However I could be wrong, NOT any D4s here and in fact never saw an old one in the flesh......just reading here on the board for a lot of years.

Other machinery and transmissions I would suspect a stripped shift collar but I don’t think Caterpillar used that system, think the shift fork actually moves the gears back and forth on the shaft to engage and disengage the transmission. So I’m betting a bad bearing has let one of the shafts get cocked out of place enough to let the gears grind out of mesh and burr the teeth enough that it can’t be shifted back into neutral.

Lubricant is generally gear oil. I could see a heavy motor oil being used and in fact have used some 50 wt Dell 100 in my D6, but I think for most operating environments/temperatures, a gear lube would be most appropriate.

I have a d4. It was my grandfather's parked 4 30 years. I've been working at getting it running. I finally achieved this. But cannot get it in any gear at all. I've pulled the shifter sprayed alot of pb blaster. Any guidance appreciated. My knowledge is extremely limited.

Good work getting her going! Nothing like a machine with family history!

So you can’t get the shifter stick to move at all? Wiggle a bit but not shift any gear?

I think that transmission will have an interlock with the clutch lever. Normal operation is transmission cannot be shifted unless the main clutch is disengaged (lever pushed forward). So look under floor plates etc on left side of transmission and clutch housing for a linkage rod connecting clutch and a lever on side of transmission. Look for missing pin, bent or broken rod etc.

I don’t have a D4 of any stripe to photograph or a book either, but I bet you will see the mechanism and recognize it now you know it’s there. If it’s all there and moving properly as you work the clutch lever back and forth, come on back and someone can help more. I’m sure there’s things that could go bad inside the transmission, but I’m thinking those would usually prevent engaging only some gears but the others would work fine.

Thank you for your reply. I will look. The shift forks are rusty, the rest bellow with view of flash light seems to be oil covered. Thank fully.

I took it off it definitely moves the clutch. Im uncertain, what too look for. But will get in again. The shift rods were most definitely rusty. All 3 are completely stagnant. I keep spraying pb blast. On everything I've seen.