case 450 dozer

[jrobe44]

I have a late 70s case 450 dozer and after about 45 mins of run time torque coverter pressure starts dropping down and eventually dozer just stalls out. I can let it sit for a couple minutes and pressure will start to build back up jus a little and i can give it gas and it jumps up but after couple more mins of running it drops again and stalls out. When i first start it up everythings fine, good pressure, drive shaft is turning, it only does this when it gets hot. Any help on what or where to start would be great.!!!

 

[alrman]

Welcome to HEF jrobe44!
Your problem is likely being caused by internal leakage. First place to look is the charge pump, it could be badly worn & losing pressure with temperature. Often when this problem exists the transmission will be slow to pick up pressure at cold start up, & be ok till temp rises.
Most likely cause of your problem could be the torque convertor.......=$$$
A flow meter is usually used to help diagnose this sort of problem, it will tell you if the pump is OK or not. Otherwise you will need to dismantle the pump & visually inspect it. Seal kits may be a little hard to come by, but not impossible, you may need to consider a new one.

 

[jrobe44]

Thanks for the info, jus didnt make sense that it done fine until and hr or so into working then start slipping

 

[jrobe44]

Anyone know of some sites to find parts for this dozer, charge pump, torque converter, etc.??

 

[jrobe44]

Also what should the flow be when checking charge pump with the gauge and normal torque converter pressure and temp?

 

[alrman]

Also what should the flow be when checking charge pump with the gauge and normal torque converter pressure and temp?

The pump flow spec is 12.3 GPM @ 225 PSI @ 2000RPM (at operating temp) & should not drop below 10GPM.
Transmission pressure is 225 - 260 PSI.

I would recommend looking for a service manual if you are thinking of tackling this job. I'm not not much help with parts suppliers over there - google is your friend

 

[jrobe44]

Thanks ver much and i gotta service manual on the way

 

[jrobe44]

Ok so i have no leaks around torque converter housing, didnt notice any lines leaking but the seal around the driveshaft where it goes into transmission is nost definetly leaking, could that be the problem?

 

[alrman]

but the seal around the driveshaft where it goes into transmission is nost definetly leaking, could that be the problem?

Would be nice if it was as simple as that, but sorry, that leak won't cause a loss of drive.

 

[jrobe44]

Ok ive been doin alot of wishful thinkin i guess, so my transmission oil is foamy, thats normal? So its pretty much one thing, bad torque converter. And possibly charge pump but more than likely the converter.?

 

[alrman]

so my transmission oil is foamy, thats normal?

Foamy oil is not normal - usually indicates cavitation (sucking air) This can come from hardened suction hoses with loose clamps between charge pump & transmission or even a worn charge pump (sucks air through the front seal). Even the wrong oil can cause foaming.
Like I said earlier, check out the pump & now the suction hoses & see if there are any improvements in operation. If that tests out OK, & the problem still exists, you will probably need to pull the convertor.

 

[jrobe44]

Thanks very much for your help

 

[robthebuilder]

It has been 10-12 years ago since I had this problem so I may be forgetting some details, but here goes;
We had a late 70's case dozer that started loosing its prime on the transmission. Originally it would lose it overnight, then someone figured out you could park it with the front downhill a slight bit & it would be fine. After a few months of doing this, the problem became worse. Sometimes it would lose prime during the day if you shut it off at lunch. Then the problem got so bad it would lose prime shifting from forward to reverse. We bought a new pump ( i do not remember what it was called, but it did mount near the alternator). The dozer never had the problem again.

 

[jrobe44]

Yea thats the charge pump, the dozer doesnt lose prime at all until it gets the temp up it always starts up with good pressure and shifts through the gears fine too. The oil starts to get real foamy after running it a bit, the only leaks ive found were on the drive shaft seal where it goes into transmission and on top of transmission right under the seat i thought maybe it could be sucking air from one if those places but have no idea how the transmission is built on the inside ive gotta parts book on order so maybe thatll help me understand it better i dunno if the pump creates a suction throughout the trans or just where the suction hose goes into it at

 

[jrobe44]

Thanks for the info everyone it is greatly appreciated

 

[jrobe44]

Can ayone tell me where the filters are for the tranmission, i havent got my manuals in yet but wanna go ahead and change them and the oil.? Thanks

 

[jrobe44]

Anyone know where the tranmission filters are located my book hasnt arrived yet but id like to go ahead and get them changed

 

[robthebuilder]

It really sounds like the charge pump. It seems lie I had to rev ours quite a bit when it would lose its prime. I cannot even remember how much it cost, may somewhere between $200-$300. It was easy to change & I am pretty sure the local case dealer had it in stock.

 

[jrobe44]

Yea im in the process of changing hoses , fluids etc. I pulled out the screen filter today and it had two handfuls of gunk on it and inside the canister it was horrible!! Ive only had the dozer a week and it obviously wasnt well maintained but it did sit up awhile according to the previous owner. The glass fuel bowl was also level full of gunk! Gonna clean out fuel system too it does have a slight miss to the engine im certain it will help. Thanks for the input.

 

[jrobe44]

Another question. Can i substitute another type temp gauge for the torque converter temp gauge they seem to be hard to find expcept for one place which was like 90 bucks.