Is300 Gear Change

[Mr.Rudus]

got a bit of a rough gear change sometimes.

get a thud from the rear when it happens. does it in auto and notice it more in manual mode.

the gearbox oil looks clean (redish) and up to the hot level.

no leaks from anywhere and diff looks dry.

should I change my box & diff fluid, will it help or cure the problem '

[ColinBarber]

have it always been this way? Only between two specific gears? In normal and pwr modes?

Occasionally I used to get it on my GS300 and GS430 as a sudden, un-smooth, gearshift. They always did it and was really just a 'feature', implementation issue, software bug - call it what you will.

If it is something that has only just occurred or has become worse then yes look at the diff oil first and then transmission fluid. Make sure you only use Toyota T-IV transmission fluid for the gearbox.

[Mr.Rudus]

been driving around all day today and has not made the thud noise once!

I feel its happening more often than before though.

its more noticeable in manual mode especially if downshifting & yes normally its around the 2nd or 3rd gear change.

will just change the fluids all round & take it from there -

[sjrainsford]

I take it you mean the oil is up to the hot level when the engine is running? Sorry in advance if that's what you meant.

But yes, I'd start with a fluid change first.