phil_ng

Last time I took my sti5 on track I developed a crunch changing gear 3 to 4 and 4 to 5 in particular after a number of laps. The problem disappeared on way home which leads me to guess its a heat problem. Has anyone had this and tried different gearbox oil? Or is this nothing to do with it?

TURBO7379

Unless you've changed it your gearbox is probably still filled with standard mineral based gear oil which is ok for road use but cannot withstand the extremes of a track day and starts to break down when it gets hot . You should change the oil asap as its chemical composition is probably been altered and it is not giving the box adequate lubrication . I recommend using a fully synthetic gear oil such as Mobil 1 gear oil and change it often if you are doing a lot of track days . You will also notice an improvement in the gearchange if you switch to synthetic .

phil_ng

Oil is changed straight after track days but you could be right about the type of oil. I dont know what my guys use - Ill have to check with them.

cwal1

Sorry to pi55 on your bonfire but it is probably the synchro's on their way out. Synchro between 4th and 5th has gone3 times now on my STI5 and it is now starting to go on 3rd to 4th.

Chris.

phil_ng

ok thanks for that Chris but how come Ive got no problem at all on the road? I think I would have the crunchies all the time if its synchro rings??

cwal1

Phil,

Hopefully it won't be the synchro problem but it seems likely from the symptoms you described. When mine started it was initially just above 6000 rpm and only then on hurried shifts. This gradually came down to just under 4000 rpm and the speed at which the gear lever had to be moved to get the crunching also lowered. Even now with the problem affecting 4th to 5th, 3rd to 4th and 2nd to 1st I only get the problem when changing gear quickly - I can avoid the crunching simply by not hurrying the gearchange. Maybe this si why you are not getting the problem on the road.

Take it out for a good blast and change into 5th at the same rev point and with the same pressure and speed you used on the track to see if the problem is still there.

If it is the synchro problem you will notice the symptoms getting worse over the next few thousand miles but apart from the crunching your gearchange should still be fine. I've had mine now for over 5000 miles and at some point in the furture I will probably have it fixed.

The likely cost for a rebuild in order to cure this is £600 - 800 and the most important consideration is to get a good gearbox builder to acrry out the work.

In the meantime try changing your gearbox oil for Silkolene Syn 5 fully synthetic, this is supoosedly the best oil you can use and seems to relieve the symptoms slightly in my experience (although others have reported that it cures the problem)

Hope this helps.

Chris.

phil_ng

Chris - sounds logical Ill change oil anyway and Im doing track day at Donnington Feb so Ill see how it goes. Thanks for reply. Phil