[greg420]

Does anyone have a reference or know what the following specs are for a Sundstrand 90 hydrostatic transmission used in a 1991 420?

Rated Continuous Pressure psi
Displacement cu in/rev
Rated Drive Speed RPM
Torque lb-ft
Max Flow GPM

I'm guessing that the currently available Sauer Danfoss Series 90 information is not the equivalent to the original Sundstrand unit in my tractor.

Thanks,
Greg

 

[jameszmcnelley]

HI Gregory, the 90 series is a whole other beast. don't let that #90 on the tag mislead you. the 420 hydro unit is a 15 series ''U-TYPE''. google Sundstrand 15 series or sauer danfoss 15 series service manual. you will find the answers to your questions there.
I have a 400, they use the 15 series also; but its an ''INLINE TYPE''. I to was misled by the 90-****, until fellow member Bob Patacky pointed out to me they were 15 series units. later, J.Z.M.

 

[greg420]

Thanks, James

I'll see what I can find.

 

[coalminer16]

Is your pump giving you problems?

 

[greg420]

I don't know yet, I'm not that far in the restoration. The tractor was used in County treatment plants for mowing and snow plowing. About three years ago, it was parked because the Onan engine had valve seat issues. When I took over as the plant supervisor, I moved the tractor into protected storage. It went to county auction last October and I was able to purchase it. The county mechanic who maintain the tractor told me that at the time it was parked the transmission was in good shape and had no problems. I have been taking my time with the restoration and am just trying to learn more about the various parts and systems of the tractor. The next item on the agenda is to purchase a new replacement engine. I don't anticipate problems with the transmission when I finally get to fire it up again.

 

[knottyrope]

my 420 sat for 7 years before I got it

Once the engine fired up there was nothing wrong with the hydro/tranny, steering, hyd lift

I had a stuck lever but that's all