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Thread: Splitter grinds low to high

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    poulson01's Avatar
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    Default Splitter grinds low to high

    Hey. Newb here.
    I just started an excavation company since no excavation company will hire me. I'm trying to get my stuff reliable and ready to work.

    I bought my old bosses CH612 dump and I'm trying to get it back to good running condition. It has a 9 speed that feels like it has a lot of miles on it. It started grinding when splitting into high range while the truck is moving. I was told that it's the splitter gear and that it's an easy fix. I'm planning on fixing it in my driveway if I can. If not, I guess I can R&R the whole tranny but I don't have enough money in the business account to do that right now. Any one ever had to do replace that gear?

    I can't get my head around how it's supposed to work. The air motor just smashes the gears together? No synchro type thing?
    I'm sure I can figure it out, I just wanted to avoid taking apart stuff that doesn't need to be taken apart or taking something apart to find out that I'd be better off pulling the tranny out and turning it in for a reman.

    It started doing it all of a sudden. No warning at all.

    Thanks in advance for any help.

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    Kranky's Avatar
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    If it's a T2090 Mack 9 speed, thats a classic problem with those transmissions.

    The hi/lo range shift synchronizer is the weak link, this also applies to the Mack T2130 13 speed and T2180 18 speed.

    Mack has updated parts available for that application, supposed to be stronger than the original.

    You won't have to pull the entire trans, you can do it by just pulling the back section off while the trans is in the truck.

    Don't try to keep using it the way it is if it's grinding on every shift into hi range. Once the teeth get worn down far enough, the range shift will start jumping out of gear whenever you put the power to it.

    .
    If you can't shift it smoothly, you shouldn't be driving it.

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    So there is a synchro behind that gear!
    Ok. I was given bad info. I'll do that right away because this truck started doing this about 3 years go!
    It is a dump conversion that was only used for local deliveries so there weren't that many miles put on it in that time. I'm sure it's close to failing though.

    What about the other gear? I'm sure the splitter gear has worn it down too a little. The tranny would need a reman then right?

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    Quote Originally Posted by poulson01 View Post
    So there is a synchro behind that gear!
    Ok. I was given bad info. I'll do that right away because this truck started doing this about 3 years go!
    It is a dump conversion that was only used for local deliveries so there weren't that many miles put on it in that time. I'm sure it's close to failing though.

    What about the other gear? I'm sure the splitter gear has worn it down too a little. The tranny would need a reman then right?
    Maybe I misunderstood your question.

    You said it was a 9 speed, so therefore I assumed you meant the hi/lo range shift (where you pull up the button to hi range when shifting from 4th to 5th) was grinding when shifting into hi range.

    A 9 speed would not have a "splitter" (where you could split each gear ratio in half in hi range (13 speed) or in both hi & lo range (18 speed).

    Anyhow, as I said before that range shift problem is a chronic occurrence on those Mack transmissions.

    If it is a 13 or 18 speed, the splitter is in the back section too.
    If you can't shift it smoothly, you shouldn't be driving it.

  6. #5
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    Nope, that's my bad. It's the Hi/Lo. I called it a splitter because I didn't know any other name for it. It isn't a Mack tranny either. It's an Eaton.

    It seems like the gear speed isn't being matched when you shift from 4th to 5th like you say. Down shifting it doesn't do it (which I don't understand).

    I can't get into it for a couple days because I'm mobbed but it's important to get this fixed. I cringe every time i shift from lo to hi. I find myself short shifting it too, so the noise isn't as bad. It really bugs me. I don't need the truck 'till Thursday.

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    Quote Originally Posted by poulson01 View Post
    Nope, that's my bad. It's the Hi/Lo. I called it a splitter because I didn't know any other name for it. It isn't a Mack tranny either. It's an Eaton.

    It seems like the gear speed isn't being matched when you shift from 4th to 5th like you say. Down shifting it doesn't do it (which I don't understand).

    I can't get into it for a couple days because I'm mobbed but it's important to get this fixed. I cringe every time i shift from lo to hi. I find myself short shifting it too, so the noise isn't as bad. It really bugs me. I don't need the truck 'till Thursday.
    That's not all that common on an Eaton Fuller 9 speed (probably a RTXF14609B, I had a CH with one of those back about 6 years ago.

    The same advice still applies, it can be fixed by removing the back section of the trans.

    I'll give you a little shortcut that may keep it from grinding quite so bad til you fix it:

    When you're ready to upshift out of 3rd gear, flip the button to hi range, and shift the stick to the position of "lo", then shift the stick up from there.

    This allows the range shift to occur with the gears spinning at a lower RPM, thus there is less grinding of the defective range shifter.

    But do fix it ASAP.
    If you can't shift it smoothly, you shouldn't be driving it.

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    Why didn't I think of that?!:bow::thumbsup:

    Why doesn't it grind going from hi to lo?

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    Quote Originally Posted by poulson01 View Post
    Why didn't I think of that?!:bow::thumbsup:

    Why doesn't it grind going from hi to lo?
    There is a forward synchro cone for direct drive through the auxiliary section (high range), and a rearward synchro cone for low range. The forward synchro cone in the auxiliary section is worn, or...there is a possibility that the air pressure to the valve and the yoke bar might be low, or maybe the O-rings for the yoke bar are worn.

    Before you remove the auxiliary section, look on the side of the transmission for a tag with numbers on it. If it's an Eaton, then there should be a number beginning with R.

    It may be something like RTO14709. I think the "T" means twin countershaft. If it's not an overdrive transmission, it won't have the "O." The first two numbers have to do with the torque rating, the third number has to do with the gearing, and the last two are the number of speeds.

    Here is Road Ranger's number 800 826-4357 I think you need option #3, then #1

    Here is a Road Ranger website for service manuals.

    Literature Center

    The Road Ranger techs are good. They know their stuff and they're helpful. Before you dive into the job, I would advise talking to them. They will guide you better than I could.

    I downloaded service manuals and parts manuals for free, but for some reason, I can't find the free downloads now. I don't know if it's my computer or a change at Road Ranger.

    I removed and repaired the auxiliary section on my 15 speed, RTO14715, and I could probably help you. One thing I would do before pulling out the auxiliary section is to find out something about the air pressure, air valves, and O-rings. You might could save yourself a lot of work.



    stonefly
    Last edited by stonefly; 04-05-2009 at 07:35 AM.

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    pdm
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    A couple of things to watch for,

    Under the brg caps are shims to set brg preload/clearance. Either reuse them or get the same thickness,( they are colour coded.)

    You will need to remove the brg caps, the counter shafts will have a threaded hole in them to put a plate across & lock/anchor them to the case for r& r.

    The c/shafts need to be timed to the mainshaft.

    When the rear section is reinstalled make sure it comes completley against the main section with out drawing it together with bolts. If not the gears arn't meshed properly & the brgs will burn out in a very short time. They can be a pita to get back together in the truck......lots of guys pull the trans & send it out for repairs...
    Last edited by pdm; 04-05-2009 at 01:14 PM. Reason: typos...
    You can't fix stupid......

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    I want to thank you guys for helping me. Getting this fixed will be an extra hour of sleep at night! This has been bugging me for weeks since I will have a lot of trucking to do soon. I really didn't want to run yet another season like this (especially since it's MY truck now!)

    So thanks again!:cheers:

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