Eaton 6 speed whining

[Larry]

Weave: My Eaton 6 speed/Cat 3126 has a high pitch whine as I am going up through the gears. It is intermittant. The whine is not there when downshifting. It is not there when I first go into the gear, but shows up as the RPM's increase. It usually occurs at about 1800+ RPM's.

Drive Safe

 

[Weave]

Is this something that just started, or has it been whining for a while? It sounds like something in the tranny is running dry. Is the oil level topped up? (Basic, but thought I'd ask). Intermittent problems are the worst ones to try to solve. Try changing to synthetic transmission lube if you aren't using it already, and see if it makes a difference. Eaton and Rockwell want synthetic exclusively in all their manual gearboxes now.
Whatever you do, don't let problems go too long with the synchro tranny- they can be expensive to rebuild, around $3-5K. (Yet are available used at any good truck scrapyard for under $1k.)
A lot of guys are swapping in 9 or 10 speed non-synchros in place of Eaton 6's or Spicer 7's. Better MPG and more power range with the less than exciting power of the CAT 3126. So if your tranny blows up Larry, I wouldn't worry too much. There are a lot of trannies that fit the 3126.
-Weave-

 

[RichM]

My Eaton 6 speed with 700,000 on it doesn!t whine but is starting to leak at the front and rear seals.Do you know if the seals ever disintegrate all at once. I guess to replace the seals the Tranny would have to be removed which is much labor,the Speedo Co guys have said that it was leaking and once in a while I see a little bit of fluid on the ground but the transmission never takes much fluid.Do you know if the Lucas stuff for transmissions would stop the leaks?
I have a friend who had a UD D unit and he lost a seal at 60 mph,lots of bucks and downtime to fix that.

 

[Larry]

The whining started just a couple of days ago. If I punch the accelerator a couple of times, it will often stop the noise. Like I said, it is not there when downshifting. I change engine oil every 5,000 - 8,000 miles and do not have any leaks. (When I park for more than one day, I always lay a large piece of cardboard under the truck to I.D. possilbe leaks.)

Thanks for the input.

 

[RichM]

Have you checked to see if your throwout bearing is lubed?On that transmission there is a plate which covers the bearing,many times lube guys don!t know about it or are too lazy to remove it and lube the bearing.I have lost 2 plates which were removed and not reinstalled so I just have left it off and always mention the throwout bearing to the ASE certified grease guy.

 

[Weave]

Is the sound definitely a whine from the tranny? Or does it sound like a high pitched whistle? You have one of those problems that unless I took a ride in the truck, it's hard to narrow down.
-Weave-

 

[Larry]

Rich: I think Weave missed your question up there in #2 about Lucas.

Drive Safe

 

[Larry]

Rich;

It appears that you were right on with the throw out bearing. I took the breather cover off and shot some grease up there. Took the truck out today and there was no whining. Hopefully the problem has been solved.

Thanks & Drive Safe