Eaton fuller 10 speed transmission making noise

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I have a question about the eaton-fuller RTX-14609B in my truck. Resently it has started making a noise in 5th/9th gear. It is hard to describe the noise but it is a very faint growling noise. You can only hear it when your on the throttle. The noise just started all of the sudden it did not increase gradually and hasn't gotten any worse. It is louder in 5th than 9th. I was just wondering if anybody has any idea what is going bad or had similar problems. I hope the tranny isn't going bad. The truck has 915,000 miles on it and this appears not to be the orginal transmission. The manufacturer tag lists a super 10 then there is a Eaton Fuller tag that list the model #s of the rears and the transmission that lists this 9spd. So anyway who knows how many miles is on it. Thanks for any info in advance.

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Every 9 speed I've been around makes noise in 5th/9th. Always louder in 5th though... It's kind of a cross between a whine and a growl. Doesn't necessarily sound bad, but doesn't sound good either....

I'd say make sure the oil is up and run it. I'm no transmission guy but I suspect you may be opening up a can of worms if you go looking for the problem. If it gets worse it will be easier to diagnose.

One truck I know of (medium duty wrecker) that makes that noise has been doing it for 10 years and hundreds of thousands of hard miles. It's still going strong.....

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Good to know. Makes me feel better anyway, haha. I was just concerned because it has been quiet until now. Thanks.

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if it has oil run it till it quits if it has been replaced it could be a 10 speed not a 9 go buy the tag on the tranny dont trust the door plate if you think its been replaced

it could be the pocket bearing makin noise if it is the pocket bearing it will jump out of gear on 5/9 when it fails you will have to hold it in gear

matt

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if it has oil run it till it quits if it has been replaced it could be a 10 speed not a 9 go buy the tag on the tranny dont trust the door plate if you think its been replaced

it could be the pocket bearing makin noise if it is the pocket bearing it will jump out of gear on 5/9 when it fails you will have to hold it in gear

matt

On our Cat powered Freightliner the operator overlooked sheared bolts holding the eaton to the engine until it got lose enough to create misalignment engine to tranny. Aluminum bell on the 3406 and serious corresion.

A handful of new bolts and the noise got much quiter. It was constantly growling when you backed off on the throttle.

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pocket bearing ?? Those transmissions haven't had a bearing [as such] in that location for many years. there is a bronze bushing pressed into the rear of the input shaft, that when the box is disassembled looks like nothing ever touched it - in my recollection. As the mainshaft floats between the two countershafts - many of the traditional transmision concepts cease to exist. Not that it would help this problem - but I remember in the early years of the twin countershaft transmissions often a slight bump in the idle speed would quiet a lot of noise. The early ones were considerably noisier than the Fuller 10 speed they replaced. I'd probably agree that if the oil was up and didn't show a bunch of metal -run'er. There are magnetic discs glued in the bottom of the case ususally, and some do and some dont have magnetic plugs

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Hey, on another note. I was wondering what type and weight fluid everyone uses in these eaton fuller tranny's. I have been told several differen't things and was just wondering what the opinions are here. Thanks.

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Synthetic 50W manual transmission lubricant

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Okay, I'm baffled. I finally got around to looking at this truck, well the transmission was very low on oil.

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I have never heard of synthetic oil evaporating. We have a fleet of meduim duty trucks at work, and since '95 all the new trucks have synthetic oil in the trans and rear diff. Some of the trucks have the original oil in the trans, as the maintenance schedule says to change it when the unit is serviced (rebuilt). I rarely add oil, and those ones have obvious leaks.

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It just makes no sense. Yeah, the synthetic oil eveaporating thing came from a not so reliable sorce. I just hope the transmission hasn't been damaged too bad.

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