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LT77 difficulty changing up from second to third

Posted: Sun Jul 27, 2014 9:58 am
by taxi3528
Changed the lt77 gearbox last year as the old one was a growler and I find difficulty in changing up from second to third when enthusiastically driven, no crunching of the gears what so ever, just does not want to engage third. This problem is only there when the revs are high and no difficulty at slower engine speeds. Got rid of the old pink oil and replaced it with new semi synthetic 5w-40, no difference in shifting.

Any ideas??

Posted: Sun Jul 27, 2014 11:34 am
by ramon alban
You could add molyslip!

as per pages 3 & 4 of the pdf available from here:

http://www.vintagemodelairplane.com/pag ... box01.html

If that does not work, check and renew if necessary the rubber bushes of the 'remote' assembly.

Image

Perceived wisdom is to use original 'rubber' as opposed to recent trend towards 'poly'. :roll:

Posted: Sun Jul 27, 2014 3:36 pm
by scudderfish
I had to tweak the bias spring adjusters on mine to get it to go 3rd-4th properly.

Posted: Tue Jul 29, 2014 11:54 pm
by taxi3528
Thanks for the tip re molyslip, will give it a try before I delve into adjusting things I know nuffin about.