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Discussion Starter #1
Just bought a 08 f550 4x4 dirt cheap with supposedly a bad tranny. Runs through all gears forward but, cannot hold reverse (Not enough piston pressure on clutch pack?)checked line pressure on hot tranny
P=50. 100=stall
R=45. 90=stall
N same as park
D=80. 120=stall
3=80. 120
2=80. 120
1=60. 120
Is there a way to check front pump output?
Could it be a stuck pc a solenoid?
Fluid looks clean
It's not throwing any tranny codes
I know pressures should be much higher just trying to get some advice so I don't throw parts at this thing
 

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You likely have an issue with reverse or direct clutch by the low pressure in reverse. However your pressure is low across the board you can try an epc solenoid and change the filter and see if that helps but IMO your reverse pressure will probably still be too low from a piston seal leak or direct clutch issue. I don’t think I’ve ever seen a burnt up low/reverse clutch set but these will burn direct all the time.

Does it shift properly from 3-5?
 

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Discussion Starter #3
Thanks for the advice.
So if I drop the pan and there's a lot of clutch material in there, I should suspect direct clutch failure? Shift from 3-5 is decent firm with no flare. The direct clutch pack is used in all gears? If i change epc solenoid what are the chances of contaminating it. I can't stand throwing money away
 

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Direct clutch is used in reverse and 5th/6th. If it shifts ok from 3-5 then you likey have a piston seal leak on reverse clutch. Pull the pan and see how things look. If the trans is making metal then your chances of contaminating the solenoid is high. If the pan is clean and magnet isn’t overloaded then I wouldn’t worry about changing it if you have to pull the trans after and re use that solenoid.

If you’re line pressures don’t improve with new solenoid then I would pull the trans and go through it.

Sent you a PM
 
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