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ATF Dextron III vs special hydraulic fluid

srexecmark

srexecmark

New member
I just got a manual from Tucker for my 1977 1642. It calls for ATF, Dextron III to use in the hydraulic system. It looks like something else, such as some kind of hydraulic fluid in in there now. Anyone have any opionions on what is best to use and do I have to flush the entire system if I add ATF now?
 
I've always used Dextron (as Tucker recommends) in my hydraulic system on my '77 1742 and it's worked well. About the closest thing to a problem I've had is that if it's very cold (say less than zero F) and I don't let the cat run for 10 or 15 minutes before I move it, the Dextron will foam a bit and often overflow the hydraulic tank

And thanks for the pics of the plow mount on yours. I was the one who asked for the photos. Interesting, but I don't think I'll be building one for mine. I found it interesting that there didn't appear to be a way to remove the mount (other than cutting it off) and even with the blade off it appeared that it might get in the way in rugged terrain.

Your 'cat is a nice lookin' one - especially for one that's 30 years old. It's not running the original grousers - the four-bolts-welded-in style are fairly late model.

Based on the model number on the spec plate (1642) I'd suggest that your 'cat started life as a pickup cab.

All in all, its a really nice lookin' unit! I'd be interested in seeing photos of the interior of the cab.
 
The plow unit comes off by removing two pins, but you are right, the mounting stays. I have the same concerns that I will have to plow snow when I don't want to. I am looking for a tree I can hang it off of, so I can keep from habing to dig for it each time I want to use it since we get 12 feet of snow in a normal winter.

Do you think there is any problem mixing the Dextron with the high pressure fluid that is in it now?
 
srexecmark said:
Do you think there is any problem mixing the Dextron with the high pressure fluid that is in it now?
Click to expand...
Do you know the origin of the 'high pressure' fluid? Do you know WHY the manufacturer spec'd the Dextron? Do you know how the spec's of the current fluid compare to the Dextron?

Sometimes a brand is recommended for a specific reason, sometimes not. I would not mix. I would want to know the specifications of what I have, and I would want to know the specifications of what is recommended. If what I have is rated at/above what is recommended, IN ALL CATEGORIES, then I would feel comfortable using it. If not, then I would switch. But I would not mix two different types unless they were identical in every way except the lable.
 
The previous owner did not have a manual. He usually errored on the over-engineered side. He used 5000 psi hoses for the plow hydraulics when 3500 psi would have been fine. I think I will drain the system and add Dextron back.
 
If you still have the Hydraulic pump Tucker installed then simply drain the old fluid after you have heated it up a bit by using the blade alot. Then after it drains and everything cools down then fill it with the reccomended oil. If its not the same pump Tucker installed then stay with what was in it and try and find out what that pump maker recomends
 
I'm not sure how I would know what hydraulic pump Tucker used that year. There is a tag on it, so I will see if I can get some info off of that.
 
I believe the pump in my 1742 is a Vickers, but I couldn't tell you the model. I replaced my pump a couple years ago with one from a '78 1744 that I have as a parts machine. To the best of my knowledge, both are the original pumps.
 
Fluid is cheap compared to a pump rebuild or replacement. I wouldn't mix Dextron with an unknown fluid. I'd drain and refill with fresh Dextron.
 
Can't remember what our old tucker used for hydraulic fluid but I do know that our Lamtrac uses univus synthetic and that the manufacturer highly recomends staying with the recomended oil. That being said, they also suggested that, if we were stuck and did have to use another brand of oil to top up the tank, that it only be temporary and that we flush the system ASAP and use only the one type of oil. Like mentioned earlier in this thread, it's a heck of allot cheaper to properly flush the system and use the correct oil for the application than to start rebuilding pumps etc...:myopinion:
 
I visited a shop specializing in hydraulic lines and hydraulic systems. They said that hydraulic oil would probably be okay, but whatever I do, don't mix them. I got a bucket of Dextron III and will drain as much of the oil I can and replace it with the Dextron. Thanks for everyone's opinions and suggestions.
 
I have a 1976 Tucker 1644 and have only used the dextron III. I have not had any problems with the hydraulics even in cold weather here in Wyoming.

Briarpatch
 
I switched it all to Dextron III. The pump was seeping a bit of fluid with the old oil and now there seems to be no leak.
 
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