Hydraulic vs Transmission fluid

scottz

Member

Equipment
1988 L2550DT-GST 2001 BX2200D HST 2016 L2501 HST
Nov 27, 2015
60
4
8
Colorado
L2501. I think the transmission and hydraulic systems share the same fluid (6.2 gal Super UDT-2); correct? If so, why two filters. Just wondering.
 

NCL4701

Well-known member

Equipment
L4701, T2290, WC68, grapple, BB1572, Farmi W50R, Howes 500, 16kW IMD gen, WG24
Apr 27, 2020
2,924
4,560
113
Central Piedmont, NC
Yes, shared fluid. 2 separate systems so 2 separate filters but they have a shared sump so the fill port, drain, and fluid are shared. Pretty common arrangement for small/medium sized tractors.
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
5,397
2,092
113
Mid, South, USA
same sump holds all the oil needed for the two or more separate systems. They all run on the same oil. HST, power steering, hydraulic system.

One filter is the suction filter for the main hydraulic pump; it's on the suction side of the pump so there is only atmospheric pressure there (about 14.5 psi)-or a little less. Keeps the biggest part of trash out of that pump. That filter is under the RH step.

the other filter is only on the HST models, under the LH step. That one is a pressurized filter, low pressure for the most part but when you remove it you'll understand why it's as heavy built as it is-has to deal with a lot more than atmospheric pressure.

gear drive (DT) tractors don't have the LH filter, only the suction filter on the RH side.

once you get into the bigger grand L's and the M series, you'll find two suction filters usually on RH side near the back.
 
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