Eaton 9 speed tranny

[Tin Lizzy]

Has anyone installed on of these in their coach?
and are you happy with it?
thanks
Harry

[boogiethecat]

I had a 9 speed (RTXO13609) for a long, long time and it was fine- I loved it....except... NOBODY could figure out how to shift the dang thing but me, so I ended up being the 100% driver.  IF I had an electronic engine I'd put in an Eaton autoshift  in a heartbeat. Same size and mounting, and these days they can be had for around 2-3 grand complete.
  Myself, having a mechanical engine, autoshift is out of the question so I changed horses last month, tossed the 9 speed and installed an Eaton 6406A fully synchronized 6 speed.  It's not quite as robust as the 9 speed but is still within specs, and I'll miss the extra gearing choices on grades, BUT that will be MORE than made up for by the fact that almost anyone can drive the thing now.
Crashboxes are great as long as you can figure them out... although it seems to not be possible for a lot of wives or friends....

[NJT 5573]

Boogie,Yes, anyone can drive it now. The weak spot is the clutch disc center. If you don't match engine speed to wheel speed with the proper gear and RPM a "crash box" won't go into gear. (To protect the clutch disc). Guess what is going to fail the first time someone puts your syncro tranny in the wrong gear? 30,000lb won't jerk like when my wife shifts her Camry sloppy, 30,000lb will just twist the splines out of the clutch disk, twist off the input shaft or drop the driveline. And thats why truck drivers and bus drivers can't have syncros in their trannys!

[boogiethecat]

Hee hee well, if that happens, I'll make sure y'all are the first to know.  I have a suspicion that these trannys work ok and this doesnt happen too often... otherwise Eaton probably wouldn't make 'em to be stuck into big trucks...  but they do...

The biggest warning I've had is from TomC who is in the biz... he says big problems will happen if I try to shift without the clutch by matching RPMs and being lazy.  But that's a no brainer.... I'll use the clutch!!!

But I do see your point.  Everything has it's rules and it's pitfalls.  If you're half careful, things will be fine and I'm sure counting on enjoying my new synchros, and not trashing my clutch!!!

Maybe I oughta invent an electronic system that senses "wrong gear", illuminates a big red light and locks out the clutch pedal!!
Hmmmmm

[TomC]

Strange as it sounds, Europe hasn't used crash boxes for over 10 years.  In '96 took a bus trip in Europe for three weeks.  The bus had a 8 spd fully synchronized transmission in one stick-no range or splitters with an air assisted clutch.  The bus driver only missed a shift twice in the three weeks.  Other transmissions are either semi-automated, where you still shift, but the transmission does the actual work of shifting, or a joy stick, etc.  U.S. is woefully behind the times when it comes to truck transmission technology.  The main reason that Eaton does not make a fully synchroed transmission is that they have the UltraShift and the AutoShift, still based on the non synchroed transmission.

As far as automatics go, I know that Caterpillar has come out with two 6 spd transmissions that about duplicate the 3000 and 4000 series Allison.  But they also have a big 8 spd that will take up to 625hp and 2050lb/ft of torque! Imagine the performance on that! Your bus would accelerate like a car and not slow down on hills-would be amazing.  Good Luck, TomC