Mrblack07
New Member
- Joined
- December 13, 2007
- Messages
- 6
- Reaction score
- 0
- City, State
- Jenison MI
- Year, Model & Trim Level
- 02 EB 4.6
Great forum guys! My current explorer (2nd one) is 2003 xlt 4.0 and I love it but last week my turbine speed sensor faulted (po715). At the time there was not any shifting problems with my explorer (a few days later it shifted poorly from 1st to 2nd). When I took it to a transmission shop and they attempted to test the sensor, they found the sensor had melted into the transmission. The cause of the overheating was a broken servo that led to the overdrive band braking and damage to the gears.
Upon further research through this website and other sites I have found these particular transmissions to fail quit often below 100,000 miles. I had my step son's Grandfather, who is an engineer (die cast), inspect my transmission and review the pdf from ratiotek (a link from this site!) and this is what his preliminary conclusions were in an email he sent me:
"Thanks Jeff,
That really helps [ratiotek pdf]. I think I see what the root cause of the piston failure is. On page 51 notice that the “Servo Strut” has an angle to it. This places a side load on the piston and the shaft which I believe causes a bind that eventually fatigues the steel and results in the broken piston. That explains why the bore gets worn and egg shaped like Shawn [transmission mechanic] was pointing out. I had never seen that type of wear before and until I saw the feature on page 51 it didn’t make sense. For years most transmission designers have placed the piston bore on an angle so that it pushes straight against the band rather than at an angle. I believe that we can show that other automobile transmission designs continue to push straight and do not have this failure. We would need to involved Shawn in order to document that but I think we can prove it..."
He believes the transmission design is at fault and there should be a class action law suite to ask Ford to reimburse consumers for the cost of the trasmission failure.
I don't know if I would seriously considered that but I am wondering about his analysis. Does he have a point? Is the servo or piston the main cause for failure in these 5r55w transmissions?
Upon further research through this website and other sites I have found these particular transmissions to fail quit often below 100,000 miles. I had my step son's Grandfather, who is an engineer (die cast), inspect my transmission and review the pdf from ratiotek (a link from this site!) and this is what his preliminary conclusions were in an email he sent me:
"Thanks Jeff,
That really helps [ratiotek pdf]. I think I see what the root cause of the piston failure is. On page 51 notice that the “Servo Strut” has an angle to it. This places a side load on the piston and the shaft which I believe causes a bind that eventually fatigues the steel and results in the broken piston. That explains why the bore gets worn and egg shaped like Shawn [transmission mechanic] was pointing out. I had never seen that type of wear before and until I saw the feature on page 51 it didn’t make sense. For years most transmission designers have placed the piston bore on an angle so that it pushes straight against the band rather than at an angle. I believe that we can show that other automobile transmission designs continue to push straight and do not have this failure. We would need to involved Shawn in order to document that but I think we can prove it..."
He believes the transmission design is at fault and there should be a class action law suite to ask Ford to reimburse consumers for the cost of the trasmission failure.
I don't know if I would seriously considered that but I am wondering about his analysis. Does he have a point? Is the servo or piston the main cause for failure in these 5r55w transmissions?