idosubaru Posted March 10, 2009 Share Posted March 10, 2009 Helping a friend with his 96 Impreza with 4EAT. When he bought it, it had brand new front tires and very warn rear tires. It started having torque bind issues. Goes away with FWD fuse installed. He had the transmission fluid flushed and new tires installed. Still has torque bind, which goes away with FWD fuse installed. So that means the Duty C is working and the clutches are bad? Link to comment Share on other sites More sharing options...
johnceggleston Posted March 10, 2009 Share Posted March 10, 2009 Helping a friend with his 96 Impreza with 4EAT. When he bought it, it had brand new front tires and very warn rear tires. It started having torque bind issues. Goes away with FWD fuse installed. He had the transmission fluid flushed and new tires installed. Still has torque bind, which goes away with FWD fuse installed. So that means the Duty C is working and the clutches are bad? yes, your assessment is correct. more fluid changes may help, the cost of the fluid is all you have to lose, but if it doesn't it will need surgery. Link to comment Share on other sites More sharing options...
idosubaru Posted March 10, 2009 Author Share Posted March 10, 2009 I'll tell him to drive it for a bit to see if maybe they'll loosen up before I go digging into it. So - the AWD doesn't allow the normal 90/10 split since they're seized. But the Duty C essentially "allows" a 100/0 split, completely disengaging the seized clutches. Is that basically how it works? I have a spare, known good rear extension housing. I can either swap that or he can pay for the new parts. Labor is free so I'll let him decide what he wants to do. I've pulled the rear housings before, is replacing the clutches much more work once the housing is off? Thanks JCE, this is the first one that someone I know has happened to, so I'll actually be doing the work this time. Link to comment Share on other sites More sharing options...
Gloyale Posted March 10, 2009 Share Posted March 10, 2009 I'll tell him to drive it for a bit to see if maybe they'll loosen up before I go digging into it. So - the AWD doesn't allow the normal 90/10 split since they're seized. But the Duty C essentially "allows" a 100/0 split, completely disengaging the seized clutches. Is that basically how it works? I have a spare, known good rear extension housing. I can either swap that or he can pay for the new parts. Labor is free so I'll let him decide what he wants to do. I've pulled the rear housings before, is replacing the clutches much more work once the housing is off? Thanks JCE, this is the first one that someone I know has happened to, so I'll actually be doing the work this time. Clutches are easy once the hub is out. Probably some of the clutches are getting stuck in worn grooves in the inner hub. I ussually file the edges of those grooves off. Link to comment Share on other sites More sharing options...
johnceggleston Posted March 10, 2009 Share Posted March 10, 2009 (edited) when i first experienced this, i learned that dirty fluid / trans could cause it. when i took the extention housing apart, i assumed it was dirty gummed up duty c valve body or passage way. and maybe is sometimes. but it can also be gummed up sticky clutch plates and grooves worn into the hubs that the plates get hung up on. the way this thing works seems bassackward to me. bad or disconnected the duty c causes binding, but does that send more fluid pressure to the clutch plates or less, more i think. there is no pressure when the car is off, and the rear output shaft is not engaged then, but i can never keep it straight. Edited March 10, 2009 by johnceggleston Link to comment Share on other sites More sharing options...
CNY_Dave Posted March 10, 2009 Share Posted March 10, 2009 when i first experienced this, i learned that dirty fluid / trans could cause it. when i took the extention housing apart, i assumed it was dirty gummed up duty c valve body or passage way. and maybe is sometimes. but it can also be gummed up sticky clutch plates and grooves worn into the hubs that the plates get hung up on. the way this thing works seems bassackward to me. bad or disconnected the duty c causes binding, but does that send more fluid pressure to the clutch plates or less, more i think. there is no pressure when the car is off, and the rear output shaft is not engaged then, but i can never keep it straight. The clutches are pressed together by hydraulic pressure, created by the transmission pump. The Duty C solenoid controls a valve (which controls a valve, I think) which relieves pressure on the clutches when activated. Duty C solenoid 'off' or disconnected- high pressure, no clutchpack slip. Duty C solenoid 'on' (FWD fuse in place)- no pressure, clutchpack should allow slip with no torque transfer. Normal operation- the TCU hits the solenoid with short bursts of power, the longer the burst of power, the less torque transfer to the rear. Dave Link to comment Share on other sites More sharing options...
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