Difficulty shifting gear when hot

[Muzdaman]

Hi guys,
Did a track day a few weeks ago and started having issues shifting on the track. It was unusually hard to find a gear and .at the end of a session in the pits find a gear was impossible. had the problem for a few sessions and on the drive home it got a little better. have not had the problem since on the street, in fact gear changes are fine and perfectly smooth.

Car is a 90, 6 month old clutch, pressure plate and flywheel and gearbox oil. Clutch slave replaced a week prior to the track day with a complete fluid flush.

the obvious difference between on track behaviour and on the street is the temperature.

clutch master maybe, its about 7-8 yrs old.

Any ideas on the cause?

[myredmx5]

Maybe you need gearshift bushes replacing!

I have a set if that is the case.

[hks_kansei]

Clutch master or slaves can cause some issues that arise when the clutch is being used often (if they've got a leak they cna be a little slow to move, not an issue at slow changes, maybe with more shifts like at the track)

Otherwise engine mounts are a possiblity, but wouldn't explain why it occured in the pits.



Is there much play in the stick while in gear? ie: how much can you rattle the stick around without moving gears? if the nylon bush at the bottom is stuffed you'll have too much play and may not be selecting gears quite right.

[Regie]

what clutch are you running?

[greenMachine]

Let me guess - Wakefield or South SMP?

Is it one gear particularly, or more than one?

Symptoms point to stuffed box. They don't like a lot of intermediate gear work, especially in hot weather. Mine died (3rd locked in, wouldn't come out until it cooled down) after a few years of Wakefield and motorkana action. Better lubrication might have helped, and the replacement 6-speed has redline and has never given a moment's worry, but I didn't know about that until after the event.

Replacement 5-speeds are cheap, but a 6-speed will set you back around $1k, plus fitting, plus oil. Search on here for lots of discussion about gearbox oil, lots ... , and whatever box you use, put some decent oil in it. Have a good look at the clutch too, while you are in there, to be sure to be sure ....

Hopefully you will find the problem to be something else, but if you do a bit of motorsport there is a good chance you have a gearbox swap in your future. If it is something else, take this opportunity to replace the oil with something fresher and motorsport-friendly, and that should help it live longer.



Edit - on preview, I see you have recently changed the gearbox oil as well as the clutch.

[Muzdaman]

Engine mounts were replaced same time as the clutch, and I've had a broken mount cause shifting issues before, this is different.

Clutch is an Xtreme HD with a 1.6 949 aluminium flywheel.

Wakefield!

More than 1 gear, shifting down into 2 was the most difficult on track, shifting up was a little easier than down.
In the pits i couldn't get 1st or reverse after a run, can't recall if i could get 2nd, 3rd etc.
The problem stuck around a fair bit after the track day. it was still difficult to find 1st at lights by the time i hit Sydney, which was a good 2 hours plus after my last run of the day.

Ill be doing a rear main seal change soon, so thats the time to change the box if I need to.
Are there any visual indicators if its the box? would a change to redline help now?? I'm guessing not?

[Regie]

very interesting

Im also running en Extreme HD clutch in my NC, and am having the same problems. A bit of a read on the net shows up similar. In other words the clutch is shiet ill be changing mine out one of these days when I'm feeling motivated