450G transmission pump

[Mike L]

Been working in said machine. Serial number is 762924. Direct drive. Hydraulics work but machine wouldn’t move. Checked transmission pressures per service advisor and it asked for 250 psi and I had 145. No significant metal in the filter. Not even really noisy. Removed pump and inspected. Definitely has some wear but I’ve seen way worse. Noticed that I got very little oil from the suction line. Removed the tank filter and it looked like this.

Now I figured I was getting somewhere. Drained all the disgusting oil and replaced. Cleaned out the screen and verified that oil could flow through it. Blew air back through inlet to the screen to make sure it was clear. Put it all back together and it moved about 5 feet . Still can’t get any better pressure. Figured the pump got starved for too long and is just shot. Removed the pump again to take in as a core and got very little oil from the suction line. Just from gravity alone I should be getting oil into the screen housing. it has some but definitely isn’t filled up. Can’t really see much down there but I’m hesitant to put a new pump on if it’s not getting a full dose of oil. Does anyone have experience with this?

 

[Diesel Dave]

Looking at the picture below, The height that the pump suction tube is positioned in the transmission housing, gravity is NOT your friend.
The direct drive dipstick is not vented which helps to shove the oil to the pump only when warmed up.
How many hours on the machine ?
.

 

[Mike L]

Not sure of the hours. Less than 1 million I’d guess. Those pictures are not what I’ve got. Mine is a hydraulic pump off the back of the engine with the transmission pump piggybacked on it with the driveshaft coming off the back of it.

 

[Diesel Dave]

Not sure of the hours. Less than 1 million I’d guess. Those pictures are not what I’ve got. Mine is a hydraulic pump off the back of the engine with the transmission pump piggybacked on it with the driveshaft coming off the back of it.

The internal transmission suction tube connects to the suction screen housing . I was just trying to demonstrate why the suction screen housing is not flooded with oil as you expected.
You will be golden after the new pump install !

 

[Mike L]

Installed the new used pump this morning. Now I’m building pressure but as soon as I release the parking brake it goes from 230-250 to about 80 and doesn’t recover until I set the brake. I’ve got to be dumping oil somewhere but I’m not sure where.

 

[Diesel Dave]

Are you able to gain normal pressure when you operate the left or right steering pedal/ lever ?

 

[Mike L]

After I replaced the filter it started to move but it’s weak. My pressure stays around 200 which is in spec. The dozer hasn’t moved in 2 years and I had drained out a pile of oily water so I suspect things aren’t great inside. It did seem to get better the longer I ran it, however it’s puking coolant out of the water pump. The customer needed it moved off a property and we ended up getting it stuck while moving it so there’s an excavator coming tomorrow to finish dragging it out and then I’ll see how far they want to go with it. She’s a fine mess I tell ya!