lt77 grinding noise in reverse

irony · Post by **irony** » Mon May 25, 2015 11:44 am

Took my kitcar for its first proper drive today on a private road. The lt77 is working well in all gears except reverse. It makes a rattly grinding noise once at about 4-5 mph but not a 1-2 mph. It doesn't slip out of gear and it reverses okay. Its not that loud but loud to be heard over the v8 by a onlooker.

I have put new transmission oil in it. I bought what Rimmers recommend. I am rather hoping I am being picky, do these boxes make a bit of noise in reverse?

DaveEFI · Post by **DaveEFI** » Mon May 25, 2015 12:27 pm

Pretty well all this sort of design makes more noise in reverse as it involves an extra gear, the teeth on which are not designed for best noise, but for maximum strength in a small size (straight cut). Other thing is the gears are more likely to be damaged through crunching on engagement - modern boxes have synchro on reverse to minimise such damage.
Has the box been repaired? Often this involves mixing part worn and new parts - a recipe for more noise than new.

irony · Post by **irony** » Mon May 25, 2015 1:27 pm

History of the box is unknown. It came with the part built car. As I said it drives okay. And reverse works but with a rattly slight grindy noise.