B7400 HST transmission fluid change

kwhites634

New member

Equipment
2003 B7400
Dec 5, 2018
21
0
1
Walkersville, MD, USA
Sorry, guys, but this machine is driving me up the wall, & I need help again.
Went to move it the other day, but it wouldn't budge; still won't. Hydraulics aren't working, either. Discovered the filter just inboard of the left rear tire dripping steadily. Judging by the looks of the ground below, it'd been leaking for a while; likely since I'd parked it several days before. Somewhere along the line the filter has been hit by God-knows-what, & is split along the rib on the flat end.

I've been glued to the Service Manual trying to get this beast back online, but I've hit a couple snags. First off, even after studying the diagrams, I'm not positive where the drain plugs are. The left one appears to be to the inboard side of the PTO shaft, but I'm not real sure on the other one; these diagrams leave a lot to be desired...too small.

The other hangup is the dipstick, on the floor pan; can't get the cap off. It acts like it should screw on/off, but twisting it isn't getting anywhere. Thought maybe it prys off; it doesn't. Related to that, does this filling plug serve any purpose other than to hold the dipstick?

I don't think it's still leaking, probably 'cause it drained down below where the filter screws on,but some of what's already leaked out looks kinda milky, like it has water in it, so I don't want to just put a new filter on & possibly contaminate 2 gal. of fluid @ $21+/gal.

Any help from someone smarter than me would sure be welcome.
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
21,507
286
83
Sandpoint, ID
I'm betting there was water in the filter and it froze and split.

I'm also betting that the main hydraulics and HST are out of hydraulic fluid.

There is 2 hydraulic oil fills on that machine and the front clutch housing fill and it does not connect to the rear Main hydraulic supply, hence they have different fill points and different dipsticks, and they have different drains.
The two systems are NOT connected.
This is non filtered non recirculated fluid that just oils a couple of bearings.

The dipstick and fill point on the floor boards is the clutch housing, that just pulls straight up, and you only fill that with a small amount.

Next post will cover the main Hydraulics.

This is just for the front clutch housing




 

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North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
21,507
286
83
Sandpoint, ID
Now for the main hydraulics, dipstick is on the right side of the seat, the fill point is under the seat.
This is the fluid that the tractor uses for all the hydraulics and for the HST.

There is three drains for this system, one on the bottom of each axle housing and one on the mid pto housing.

Main dipstick


Main fill Point


Axle drain plugs


Mid PTO drain Plug
 

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