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Hi everyone, I’m new to this site and I was hoping maybe someone can offer some advise. I apologize for the long post but I wanted to include as much detail as possible.

My son recently purchased an early 99 (4/1998) F350 DRW 7.3l 4R100 4x4 with 236K miles. The problem is it will not shift beyond 2nd gear. At 233K miles the original owner lost all forward gears with only reverse left. He took the truck to a repair shop that works on his company vehicles and they installed a Jasper Reman transmission. He picked up the truck (this is his personal truck) and drove it for around 1500 miles and then started having problems with it not shifting beyond 2nd gear. He took it back to the shop where they installed another Jasper Reman transmission under warranty and it still did not shift beyond 2nd gear. Supposedly they reflashed the ECM and it started shifting fine again for another 1500 or so miles and the same problem came back. He took the truck back and they could not find the culprit. At this point he needed a dependable truck and purchased a new one. My son had been looking for a nice 7.3 truck and he took a chance with this one.

I’m a mechanic and have been trying to help my son work out this issue. First off the truck has 1st, 2nd, and reverse. The trans fluid is clean and full. There are no codes stored and the O.D. Light is not flashing. I have checked both the input and output speed sensors and they are a steady 1.8K ohms. The ABS sensor is a steady 1.5K ohms. The truck runs well and shifts well from first to second and into reverse too.

My sons friend is a transmission mechanic at a local shop. He could not find any codes stored with his scanner. On the test drive he could see the ECM commanding 1st gear , 2nd gear, and then 3rd gear but it obviously was not shifting into 3rd. His scanner was showing that the ECM thought it was in 3rd then it commanded a 4th gear shift but it still was in 2nd gear. The friend is stumped too

My son and I have researched the solenoid shift strategy and we know both valves are working since we have 1st and 2nd gear. We found some information that instructed to unplug the solenoid harness on the right rear of the transmission to simulate a 4th gear shift, so we unplugged the harness and drove the truck around the neighborhood block in 4th gear confirming that we have a 4th gear in this Jasper Reman transmission. We understand the shift strategy to be as follows

1st. SS1 on SS2 off
2nd SS2 on SS2 on
3rd SS1 off SS2 on
4th SS1 off SS2 off (what we were able to mimic with an unplugged solenoid harness)

Any help that you could provide would be greatly appreciated.

Thank you
 

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What is the PCM showing for TP (throttle position,) VSS (vehicle speed,) TSS (input speed,) OSS (output speed) and engine speed when it should shift to third gear?
 

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What is the PCM showing for TP (throttle position,) VSS (vehicle speed,) TSS (input speed,) OSS (output speed) and engine speed when it should shift to third gear?
Hi Mark, I am sorry for the delay, my scanner was not working properly so I had to wait for the new one to arrive. Today I was able to get the information that you are asking about. I recorded 4 sessions and they all seem to be very close to each other. These are the readings as the PCM is commanding a 3rd gear shift. TP 21.78% TP 1.09v RPM 1990.2 OSS 1222 TSS 1879.2 VSS 30.06 MPH On my last data log I was trying to see if the PCM was going to command a 4th gear shift as it did for my sons friend who is a young transmission mechanic. It did not command a 4th gear shift for me but it finally threw a code that we have not seen before (P0782 2 to 3 Shift Fault). Thank you for your help Mark
 

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Your TSS divided by OSS shows a ratio of 1.54:1. That's second gear. So it's commanding third, but not shifting out of second.

Does reverse work correctly? If so, that shows that the direct clutch is working. The direct is used for third gear and reverse. If reverse works I would suspect a stuck 2-3 shift valve in the valve body. If reverse doesn't work, the direct clutch is hosed. Not commanding fourth gear is because it won't shift to third gear.
 

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Discussion Starter · #6 ·
Your TSS divided by OSS shows a ratio of 1.54:1. That's second gear. So it's commanding third, but not shifting out of second.

Does reverse work correctly? If so, that shows that the direct clutch is working. The direct is used for third gear and reverse. If reverse works I would suspect a stuck 2-3 shift valve in the valve body. If reverse doesn't work, the direct clutch is hosed. Not commanding fourth gear is because it won't shift to third gear.
Hi Mark, yes reverse works correctly and seems to be strong. I forgot to mention in my previous post that after the P0782 code was thrown the OD light did begin to blink on the shifter. I cleared the code but it sounds like it is all related to what you are saying about the 2-3 shift valve being stuck. I will look into replacing this valve and getting back with you on the results. Thank you
 
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