Bad synchro - replace trans - grinding gears

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by RepoweredRookie, Aug 16, 2022.

  1. Hammer166

    Hammer166 Crusty Information Officer

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    This exactly why Super 10's got such a bad rap. Guys would slip them out of the 4 or 5 hole and let go of the stick and they'd try to range shift as soon as the shifter moved from the right gate.
     
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  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    That's not a 10 Eaton, and Eaton never had shift solenoids
     
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  4. kranky1

    kranky1 Road Train Member

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    There was nothing wrong with those transmissions. They dropped the ball on the newer auxiliaries information wise on all the transmissions. And timing too. Those were supposed to be pre-selected. In a lot of cases the people driving them were coming from earlier Eatons that weren’t to be pre-selected. Shifting the auxiliary section when the main was in neutral on the 2-3 4-5 6-7 8-9 shifts like was habit for them on the earlier 13’s killed those pretty quick. All the Eatons suffered from that change for a few years. I know a couple people who just loved those 10spds though, and got big miles out of them.
     
  5. kranky1

    kranky1 Road Train Member

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    Slave valves and pistons. Some refer to them as a solenoid. I’m still not sure what transmission it is. In one post it was both.
     
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  6. AModelCat

    AModelCat Road Train Member

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    Yeah a Rockwell transmission is an entirely different beast. Aparently they use solenoids to control air rather than a master air valve in the shift knob like Eaton's do.
     
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  7. Hammer166

    Hammer166 Crusty Information Officer

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    I've always got a kick out the guys who trash them and praise 13/18 in the next breath. It's the same tranny with a 3 speed main and a shift tower driven range shift.

    They were awesome on flat ground, it was nice to be able to run around and never move the stick unless you dropped below 35mph. Like any 10 speed, the gear steps were too big and you always ended up coming off grades slower than you could with a 13/18.
     
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  8. kranky1

    kranky1 Road Train Member

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    Cousin had one in one of his flower power mobiles. That truck only hauled insulation and plants. The 12.7 in it could handle the ratio steps with those light loads and it was a fuel mileage machine. Only ran On/Fl.
     
  9. Trevor 57

    Trevor 57 Light Load Member

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    In an Eaton Road Ranger generally the range synchroniser packs it in if you are swapping between high and low with the main trans in neutral and you are rolling to a stop. This is quite a common practice with drivers. But it put both parts of the trans in neutral and the synchro is fighting to slow things down to match the speeds, but no where to go. If you listen you can actually here the synchros squealing
     
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  10. kranky1

    kranky1 Road Train Member

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    You would think that noise would lead one to believe doing that wasn’t a real good idea wouldn’t you. Only hear it now and again out of the highway trucks anymore, most of them are automated. But in the city, between gravel trucks and guys hauling containers with old iron you hear that all around you in traffic.
     
  11. RepoweredRookie

    RepoweredRookie Light Load Member

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    So guys I guess it is the Rockwell-Meritor transmission. I cleaned off the trans tag and researched RM as Rockwell Meritor. Went to Meritor’s website and ordered the “Air Slave Valve Assembly” ($310) and the “Air Filter Regulator Assembly” ($110) per the responses you guys advised. I also found 2 guys on Youtube that replaced either 1 or both of the recommended valves for the same exact issue-grinding when selecting High gear 6. So I’m pretty certain you were right about the resolution. Going to install 1 or both valves and report the results next week. Thanks to everyone for responding, y’all probably saved me $4600. Thank you!
     
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