Cat 973 track loader

The info I have shows it to be a 1988 model produced in France
Production run from 1982 - 1995.....only 307 units built.
Hydrostatic trans, 3306 engine.
Improved undercarriage at #164
Single section implement pump & dual setting relief valve at #167

Seems like a limited production machine but I don't know of any issues.
Can't answer your valve question.

They're quite a good track loader, and I don't know of any major problems with them, that need to be watched or looked out for.
The 3306 is robust and reliable, and the hydrostatic transmission doesn't have any major faults that I can recall. I drove one for a few months in 1996 on a landfill site, it was a nice machine, and I liked it.

The main problems to watch for would be related to suspect repairs and lack of maintenance on the previous owners behalf. I can't see any reason why you couldn't fit anti-drop valves. There's nothing excessively complex about the 973 loader hydraulics.

The Cat SNID book from Cat shows that they first came out in 1982 and were made in Japan.

I seem to recall 91L's being asian machines too Ken. There where a a bunch of them around. Early ones had some serious problems with the travel motors but Cat road the learning curve with them and any around now will have more durable parts in them. See if you can work it for a day before you buy it. If you can work hard for a whole day and it not kick out of travel and need to be reset to continue driving it's a good one. Otherwise it likely needs a pair of exchange drive motors.
Later Bob

According to my "sometimes right" source they did begin in 1982 and were made in:
US....26Z
US....32Z
France....66G
Japan....90L
France...91L
France ...86G

The highest production number is the 86G at 3,583 units with production to 2002. Typical weight about 55,000 lbs.

Must have been the 90L I was thinking about OM. Remember I couldn't read any of the tags and stickers in the cab. I think the ones we got where on a logging job in Asia and didn't work out so Cat swapped them for D7's. Hugh Piper was involved in the development of these machines.
Later Bob

The Cat sales book (SNID) shows both the 90L & 91L were made in Japan but that,s where it shows these two were made.

Hi SJ,
That does make more sense as the 91L is a LGP machine and the 86G is also a LGP unit produced at the same time.