[Mk2] [Turbo] Gearchange at high revs

[2tmike]

This has been raised on an earlier thread by someone else but I don't think it was ever really resolved so ......
Rev 5 turbo is really hard to do an up change at high revs, 3rd to 4th and 4th to 5th. At low revs it is completely fine with no sign of weak syncros or an obstructive change. Take it to over 5k though and try to change up from 3rd to 4th and it's totally blocked and you have to wait for everything to slow down before a gear can be selected. The clutch and hydraulics are in good condition and the bite point normal so I'm completely certain that is not the problem. Gearbox oil is less than 25k miles old and clean. There doesn't seem to be any obvious problem with engine or gearbox mounts, so any ideas would be welcolme !!!

[mrturbotom]

Sounds like clutch dragging at high rpm

[2tmike]

Clutch was replaced by Rogue less than 5k miles ago and master cylinder has been rebuilt since then. Bite point is completely normal with minimal free play on the pedal adjustment so I'm not sure how this could be a factor ? The whole gear change is generally heavy compared to my st205..

[thomp1983]

Nip it back to rogue and ask them to have a look you shouldn't be having issues after 5k

[Ja99a]

I have had this twice and cause by two different things.

1. lazy syncro basically the 4th syncro was lazy when pulling rpm.

2. the linkage on the gbox wasn't tight and the gear wouldnt go in at higher rpm, think it was the rotational cotter pin thing that was loose.

In both cases it couldn't be forced inwith speed etc.

[Peter Gidden]

Most likely cause is synchros or silly super-short ebay short shifter.

[asdrewq]

To check clutch drag: warm car up, stop on flat surface, rev to 5k+ in gear with clutch down and see if car moves at all.

I'd suspect clutch adjustment causing slight drag or wrong gearbox oil. I really don't think these boxes take well to specialist gearbox oils e.g. redline shockproof.

The MR2 pedal is heavier than the ST205, iirc the mr2 clutch pedal assembly has 2 resistor springs, the ST205 only one.

[2tmike]

Linkages are fine, standard shifter and bearings fitted in place of rubber bushes. I suspect that the dragging clutch suggestion was mostly right but the reason behind it isn't really clear. By moving the bite point nearer to half pedal the change up at high revs is much much better but clearly any free play in the pedal has gone so maybe not the best long term solution.

[bobhatton]

By moving the bite point nearer to half pedal

That is the right place for it.
You can adjust the free play with the stop.

[Nails]

We changed the clutch fluid and adjusted the pedal on outruns yesterday after he had similar problems after a clutch and gearbox oil change. Its spot on now. Very suprising how much lighter the pedal is after a fluid change too so might be worth a go.