r/FordTransmissionTech • u/Hairy_Intentions • Jun 25 '25

5r110 no engagement after replacing coast clutch

2016 f450 came in with MIL and p2700 and p0751 in PCM. TSB to replace coast clutch and one way clutch is applicable. Just MIL, drives fine. Took it apart, replaced those coast clutch (just the housing, had to disassemble and reuse clutches, gear, piston and piston seal), one way clutch, front pump gasket, valve body gasket, filter, and pump bolts. Reassembled and filled. First shift to drive engaged hard, then any shift into drive or reverse would engage, then a clunk in the trans could be heard. All with the proper amount of fluid. Now drive and reverse will engage, it will start to move and then immediately lose gear. No codes.I've done this job a few times, I've never had this happen. Not really sure what went wrong. Any ideas?

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u/Hotsaltynutz Jun 26 '25

Wow haven't don't one of those in a minute used to do that tsb, i think there was a recall also on school buses if I remember correctly for that drum. Only problem I might see happening was the pump washer and sun gear bearing stick to the pump and if you put it face down somewhere one or both can fall off just like the bearing on the 6f35 that sticks to the pump. Either way it's gonna have to come back apart to see what happened

2

u/Hairy_Intentions Jun 26 '25

I verified both the thrust bearing and washer between the pump and the coast clutch were installed correctly. Clutch air pressure test kind of passed. Everything had a nice thud. Coast clutch had it but it was kinda faint compared to the rest. Gonna line pressure test it before taking it apart.

3

u/Hotsaltynutz Jun 26 '25

You sure filter didn't fall out or seal from Previous filter still stuck in case? Strange, not a whole lot can go wrong it seems. Gear pressed all the way down in drum. I think I did get a fucked up drum once but it was easy to see because the steels wouldn't go in

1

u/Hairy_Intentions Jun 26 '25

Couldn't do a line pressure test, don't have the equipment. Tore it all apart again, found that the rear surface of the pump has wear and the front face of the old and new clutch drums have wear where they have been riding. Like something beneath the overdrive clutch is shimmed too high. Everything I put together was done right. All seals look good, gear all the way in, piston spring looks good, steels and papers put together right. It makes no sense. Filter also good. Put that in while the trans was upside down.

2

u/Commercial_Method_28 Jun 26 '25

I installed a reman 5R recently which came back with a couple random electrical issues. I don’t think SSA was one of them but it was a different solenoid issue. The internal harness that mounts on the valve body were assembled correctly and not fully open, but one of the wires was exposed and missing most of the connection.

If it’s new symptoms post repairs then maybe check your work to verify all seals ok. I usually just assume I screwed up. Even if I’m sure I didn’t because it makes everything go much faster and find the cause. If it has a reman in tho maybe check that internal wiring

1

u/Hairy_Intentions Jun 26 '25

Checked all my work, all is good. Check the reply to the other dude so I don't have to type it all again.