Possible HD16DP acquisition

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   Greetings all. Who knew becoming a land developer would find me owning such a variety of heavy equipment but here I am again with my potential acquisition of an Allis Chalmers HD16DP-7748. I do not know for certain but I am going to put this around the 1967/68 vintage. It's certainly larger than my D6.

I went to check this bad boy out and it is in unbelievably great shape... everything works very well accept an issue with what I believe to be the transmission. The current owner explained that the unit would not move when he purchased it. Found the transmission dry... no fluid. They filled it up and that got it to moving. Over time it has retreated into a process of firing up the motor... than working the forward/reverse back and forth until the machine begins to move... initially it will move about 10 feet in both direction and then build up as you continue to cycle back and forth. Ultimately it will reach a point that it will move well for the day until such time you shut it down and let it sit. You then will have to repeat the process. I have ordered a complete set of manuals for it but do not have them yet. Thought I would look to see if there was an A-C old timer on here that could lend some pointers.
I have posted this info in other tractor sites and have others telling me to run... don't walk... away from this purchase.  Those that bother to explain why suggest parts are an issue.  I'm finding it hard to even walk away from this.  The unit is in very nice shape... all movements work very well accept the issue I spoke of above.  My primary purpose for purchasing is the monster rake on the back and a 4 way blade.  My current CAT D6 has neither and I am working a project that requires both.

Any comments?

Edited by hdokes - 21 Sep 2025 at 5:25pm

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hdokes Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 21 Sep 2025 Location: Midwest Points: 3	Post Options Post Reply Quote hdokes Report Post Thanks(0) Quote Reply Topic: Possible HD16DP acquisition Posted: 21 Sep 2025 at 4:53pm
	Greetings all. Who knew becoming a land developer would find me owning such a variety of heavy equipment but here I am again with my potential acquisition of an Allis Chalmers HD16DP-7748. I do not know for certain but I am going to put this around the 1967/68 vintage. It's certainly larger than my D6. I went to check this bad boy out and it is in unbelievably great shape... everything works very well accept an issue with what I believe to be the transmission. The current owner explained that the unit would not move when he purchased it. Found the transmission dry... no fluid. They filled it up and that got it to moving. Over time it has retreated into a process of firing up the motor... than working the forward/reverse back and forth until the machine begins to move... initially it will move about 10 feet in both direction and then build up as you continue to cycle back and forth. Ultimately it will reach a point that it will move well for the day until such time you shut it down and let it sit. You then will have to repeat the process. I have ordered a complete set of manuals for it but do not have them yet. Thought I would look to see if there was an A-C old timer on here that could lend some pointers. I have posted this info in other tractor sites and have others telling me to run... don't walk... away from this purchase. Those that bother to explain why suggest parts are an issue. I'm finding it hard to even walk away from this. The unit is in very nice shape... all movements work very well accept the issue I spoke of above. My primary purpose for purchasing is the monster rake on the back and a 4 way blade. My current CAT D6 has neither and I am working a project that requires both. Any comments? Edited by hdokes - 21 Sep 2025 at 5:25pm

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Eric B Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 09 Feb 2012 Location: British Columbi Points: 970	Post Options Post Reply Quote Eric B Report Post Thanks(0) Quote Reply Posted: 22 Sep 2025 at 8:50pm
	It sounds to me that a screen for the oil pick-up is restricted and while the oil is cold and thicker it's short of oil to maintain pressure. As the oil starts warming up and gets thinner there is enough flow to keep everything working. I've never owned an HD16DP so I can't give any details but just sharing this principle because it has been the scenario with other equipment at times. Please let us know when you find the fix, thanks. I have owned 13 bulldozers over a few decades.
	Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!

HD6 Merv Members Profile Send Private Message Find Members Posts Add to Buddy List Silver Level Access Joined: 03 Aug 2010 Location: New Zealand Points: 498	Post Options Post Reply Quote HD6 Merv Report Post Thanks(0) Quote Reply Posted: 23 Sep 2025 at 10:55am
	Yes agree with previous poster; most transmission drive issues stem from transmission pump supply issues; and this applys to all crawlers and all makes. Blocked suction screens, collapsed suction hoses, suction air leaks etc. All just a prt of regular machine maintence. HD16DP was from all accounts a very good machine. Alot of parts as in all AC stuff 'can' be a issue; but alot of their engineering was standard SAE stuff too, not special just to 'me' stuff like cat can be at times. As in most machinery cases; alot of it depends on your/or your helpers, machinery 'nous' and abilitys
	tits tyres and tracks they all cost you money

Doughd16b Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 01 Sep 2022 Location: Nc Points: 33	Post Options Post Reply Quote Doughd16b Report Post Thanks(0) Quote Reply Posted: 23 Sep 2025 at 1:32pm
	I can help you out sir, too much to type,252 916 2927 anytime

Doughd16b Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 01 Sep 2022 Location: Nc Points: 33	Post Options Post Reply Quote Doughd16b Report Post Thanks(0) Quote Reply Posted: 23 Sep 2025 at 3:44pm
	Its a mid 1966 year model btw

hdokes Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 21 Sep 2025 Location: Midwest Points: 3	Post Options Post Reply Quote hdokes Report Post Thanks(0) Quote Reply Posted: 18 hours 9 minutes ago at 4:24pm
	Went down to where the HD16 is located yesterday and replaced the suction hoses on it. It looked like this could be the issue as the upper hose was not tight and could allow air to be sucked in to the pump but it did not alleviate the issue. Took a set of pressure gauges with me and checked pressure at the filter. Someone had already retrofitted this dozer with a relocated filter up next to the seat and we checked the pressure at that point. We had 160psi and found that the filter was clean and free of debris. Additionally, as we drained the fluid through the suction tube which is on the output side of the internal transmission screen and the fluid flowed freely and was absent of any contamination we believed the screen to be in good shape and did not drop the transmission pan to find out. This dozer has a modulated clutch and we then checked the pressure at that point and had no pressure... zero. Working with Doughd16b we found that there is a way to test the modulator itself but we did not have the proper tools with us to accomplish this yesterday. The fella that owns it will have those tools tomorrow and will be able to perform the test. If successful it will indicate that the modulator is the issue and I will need to open it up and look for an obstruction or failed seal. I learned more about what led up to the dozer not moving. The previous owner had changed the hose that goes from the modulator to the heat exchanger (this dozer has two heat exchangers). After doing so is when they said it stopped moving. As this hose feeds hydraulic fluid to the modulator and the point of pressure test was on the output of that modulator we believe there is some kind of obstruction, perhaps caused during the replacement of the hose. It is our understanding that the removal of one of the eight hoses going into this modulator and capping it will tell us for sure if the issue is in the modulator. If the dozer goes into gear and moves after doing so then the modulator is likely the culprit.