Transmission wouldn't shift in heat

[Ben]

Got a new one (for me anyway). Stuck in Melbourne traffic last night, 35+ degrees and could get reverse, or and other gears without massive struggle.

Tell me it was just getting too warm and there ain't something more expensive coming my way!

[Dustbowl]

Hahaha No you aren't about to find a hole in your trousers where your wallet once was :p
You had lost a sensor to heat soak, it sounds like (and I'm guessing) a TPS, but it could possibly be a Crank_Position_Sensor as well.

Start by checking the terminals, but I'd say it died in the heat.

(Excuse underscores, the ad links are back :roll: )

[bonza]

Got a new one (for me anyway). Stuck in Melbourne traffic last night, 35+ degrees and could get reverse, or and other gears without massive struggle.

Tell me it was just getting too warm and there ain't something more expensive coming my way!
are we talking manual or auto? mileage of vehicle/transmission?

[Ben]

Sorry, its a 2000 5 speed manual.

Started to do it again after 2 hour drive. Not as bad, but starting.

[MidnightMods]

does your car share the brake and clutch fluid?
If so how long ago was it changed?

[bonza]

seeing it is all gears probably clutch related, most likely master/slave cylinder.
as previous post, when was fluid last changed. brake and clutch fluid does 'off' being hygroscopic and absorbs water from the atmosphere causing steam in the fluid and will thus compresses causing the master and slave cylinders not to fully stroke. that is probably why it occurs when its hot

any way, forget about the reasons why, drain and replace your clutch fluid. do your brakes while you are at it. use DOT 3