Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: gear box rebuild cost

  1. #1

    Join Date
    Dec 2011
    Location
    Clark Fork Idaho
    Posts
    54

    Default gear box rebuild cost

    Have a friend interested in purchasing an Aeroteck (?) with Rotax that has 900 hours on it and wondering what the Gearbox rebuild cost would be in round figures. I understand it's a good idea to do it at 1,000hours.
    Thanks, Jeff

  2. #2
    Senior Member
    Join Date
    May 2011
    Location
    MN
    Posts
    469

    Default Re: gear box rebuild cost

    I sent mine to Mississippi Light Sport (?) And if I remember correctly it was around $230-250 with return shipping.

  3. #3
    Super Moderator Av8r3400's Avatar
    Join Date
    Jan 2009
    Location
    Merrill, WI
    Posts
    3,044

    Default Re: gear box rebuild cost

    Gearbox maintenance should be done more frequently than 1000 hours.

    3-400 hours is a better schedule.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
    YouTube Videos

  4. #4
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,960

    Default Re: gear box rebuild cost

    If you are running Mogas the Line Maint manual says 800 hours. I run mogas and have 700 hours on my gearbox with no indication of problems yet. Friction torque in spec, no funny noises or kickbacks, smooth idle, etc. I will go "on condition" but I agree that after 400-600 hours you need to start paying close attention to the gearbox.

    FWIW I also am going "on condition" for my carburetors. The book says to disassemble and inspect every 200 hours; mine are now at 700 hours and have never been disassembled. Engine is smooth at idle and up, and I have checked sync every 100 hours, but have not needed to readjust for 300 hours. Why try to fix what ain't broke. I will be doing the 5 year rubber replacement when that time comes (soon) and will disassemble them then.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  5. #5
    Senior Member
    Join Date
    Nov 2012
    Location
    Desert Aire (Mattawa), WA
    Posts
    218

    Default Re: gear box rebuild cost

    I had Hal Stockman R & R mine (for the first time) at 1,300 hours. He replaced the Belview (large spring) washers and re-shimmed as req'd. The only wear was about .010" on the Belview washers which was 'normal'. All for about $200 and quick turn around. Thank you, Hal! In my opinion, some of the Rotax intervals are way conservative with the exception of oil changes. I do 50 hrs. and run 99.9 MOGAS.

  6. #6

    Join Date
    Nov 2011
    Location
    Tracy CA
    Posts
    3

    Default Re: gear box rebuild cost

    Gearbox Inspection cost depends on parts used and the extent of the inspection. Calendar age and hours along with extent of previous inspections also very price. A gearbox on the bench typically takes 1-2hrs to disassemble clean and inspect. If the bearing and seal are replaced, that will add about 175$ in parts. The 3 disk springs should almost always be replaced with a few exceptions at $75. Gearset, thrust washers, clutch hub and prop shaft can increase cost if fracturing or wear is detected. Your clutch may be due for a cleaning and adjustment and that adds 1-1.5hrs of labor.

  7. #7
    Senior Member
    Join Date
    Jul 2013
    Location
    Highlands Ranch, CO
    Posts
    404

    Default Re: gear box rebuild cost

    If you are running Mogas the Line Maint manual says 800 hours.
    If you are running a gearbox with an overload clutch and over 30% leaded fuel annually the manual says 600 hrs.

    If running strictly mogas with an overload clutch the manual says 1,000 hrs.

    If running a gearbox without an overload clutch the manual says 600 hrs. no matter what type of fuel.

    If you are running a gearbox with an overload clutch you are also supposed to check the friction torque every 100 hrs or at annual (whichever comes 1st).

    Maintenance schedules are preventative. If you are waiting until it's "broke" hopefully you are on the ground. Can't see bearings, seals, springs, washers, pitting or spalling without opening it up - whether it runs "smooth" or not! Actually you could see some of it with an endoscope.

    Do what you want, but keep in mind you as the owner are responsible for maintaining an airworthy aircraft.

    YMMV, Greg

  8. #8
    Super Moderator Av8r3400's Avatar
    Join Date
    Jan 2009
    Location
    Merrill, WI
    Posts
    3,044

    Default Re: gear box rebuild cost

    I've serviced several gearboxes (including my own) that had far less than 1000 hours, one at 200 hours, that needed to be worked on. Heavy props (particularly Warp Drive) are notorious for shortening the life on a gearbox. It's not a difficult job to do and adds considerable life to the engine.

    Routine maintenance parts (shims) and sealant can be less than $20.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
    YouTube Videos

  9. #9
    Senior Member
    Join Date
    Jul 2013
    Location
    Highlands Ranch, CO
    Posts
    404

    Default Re: gear box rebuild cost

    Quote Originally Posted by Av8r3400 View Post
    I've serviced several gearboxes (including my own) that had far less than 1000 hours, one at 200 hours, that needed to be worked on. Heavy props (particularly Warp Drive) are notorious for shortening the life on a gearbox. It's not a difficult job to do and adds considerable life to the engine.

    Routine maintenance parts (shims) and sealant can be less than $20.
    I agree Larry.

    The other two most prominent causes of gearbox wear are:

    1. Poorly balanced prop - Rotax recommends dynamic balance, but it should be mandatory!

    2. Improper oil type, infrequent oil changes and operating oil temperatures out of spec for extended periods.

    Less prominent is, frequent overloading the prop at improper rpm.

    YMMV, Greg

  10. #10
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,960

    Default Re: gear box rebuild cost

    As further clarification of my "on condition" statements:
    First, Greg is correct in that the manual states 1000 hours (not the 800 I was recalling) for 912ul/uls with overload clutch and less than 30% use of 100LL.

    My use of "on condition" maintenance comes from closely following Mike Busch's excellent webinars on the EAA website. This guy is a nationally recognized and awarded AP/IA mechanic and owner of a large maintenance company for mostly certified aircraft. He is a strong proponent of "on condition" maintenance where appropriate. First of all it doesn't apply to ac in commercial use, and doesn't apply to items likely to catastrophically fail like rubber and hose and belt replacement. The items it does apply to are things that rarely fail catastrophically, but start giving warnings well ahead of complete failure, like cyl heads, piston rings, carbs, many bearings, etc. Don't take my word for this but watch his webinars in the EAA webinar archives. "On condition" is not for everyone, but requires either a knowledgeable hired mechanic watching things, and/or an owner that is very comfortable mechanically and knows the tests and warning signs to watch for.

    In my own case I feel the gearbox is one of those items that will give warning (sure there is a small risk of sudden failure as is true of most items) if you pay attention and know what to look for; this also true of carburetors in my opinion. That said, I will definitely replace rubber parts near the 5 year recommendation, tear down the carbs, maybe even overhaul the gearbox during this convenient downtime since it will be near the 1000 hours. Everything has to be done with common sense rather than blindly following a book, although following the book is never bad. I believe following Mike Busch's philosophy gives the best combination; after all, going "on condition" may cause you to repair some item far sooner than the book says.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •