Gearbox Issue - Think I`ve Cracked It !

[GTB 53]

Since day 1 my gearbox has not been acceptable in its operation. 1st to 2nd has always been crunchy, 2nd to 3rd intermittently crunchy and general gear selection poor. It would often clunk all the way to the back axle when engaging first which is a sure sign the clutch is not fully breaking and is dragging. The car went back to Toyota twice for "adjustment" with no improvement. I fitted Redline MTL oil and had Abbey fit MTEC shift springs. A little improvement but not significant. I read on the FRS forum about altering the bite point lower and tried this. Whilst it improved driveability it actually made the problem worse and the placebo effect soon wore off.

 

I have been convinced from day 1 that the issue owners experience is clutch drag. Have experienced this so many times on bikes with cable operated clutches if the cable is not kept well lubricated and adjusted.

 

Yesterday at The Trundle I sat in Subota Boys car and felt his clutch - ooer ! Totally different to mine. After he sat in my car we both agreed that my clutch felt like it had air in it. I was all prepared to do some bleeding this weekend when today I strayed across an excellent website. Read it through a couple of times and it all made sense. Watched the video a couple of times and the guy actually has a clutch assembly on the bench to show you what to do (same as moving bite point). I set my clutch this afternoon EXACTLY how he says and double checked it. The actuator is on top of the clutch housing so you don`t need the buddy he mentions to check actuator operation.

 

I have just been out for a spin and can`t believe the difference. Bite point is probably now higher than from when I got it but gearchanges very very good. You can just feel the massive improvement. No baulking, no crunching and much much smoother. The pedal is more solid and feels exactly how it should, not like it has air in it.

 

I highly recommend anyone with the crunchy nut gearbox to try this. It is just a 10 minute job. Read the website and watch the video a couple of times. The setting is quite critical it would appear. Perhaps this car is quite sensitive to the set up and a general assembly at the factory is not sufficient ?

 

I`ll keep you posted but so far very very impressed.

 

Toyota could do with taking note of this site:

 

http://www.jackstransmissions.com/pages/clutch-drag-kills-synchros

 

and the video here:

 

https://www.youtube.com/watch?feature=player_embedded&v=vYJxQyjIhUw

[Lauren 2259]

Good stuff, for a moment there when I opened the thread I was wondering how you cracked your gearbox! 

 

Is there no vid better than 240? That's hard work watching as you can't see what he's doing!

[Guest]

Great find. It's stuff like this that makes forums priceless.

[Mark-in-Stoke 488]

If this works a statue of you will be commissioned.

[Keethos 842]

Awesome stuff, glad you finally got this sorted and can fully enjoy the car!

[Captain Duff 79]

I wonder if this is the issue for all those with 'cold' 1st/2nd gear problems (thankfully I'm not one of them)? If it is then it does make you wonder why Toyota and Subaru themselves don't recommend to dealers to check this as a potential remedy?

[GTB 53]

Drove to work this morning 8 miles, very cold. 1st couple of times 1st to 2nd stiff but no crunch. Everything else excellent with no graunching, clunking, baulking etc etc. Even with clutch depressed for several seconds I would previously get a clunk all the way to back axle on occasion. The idea IS to get maximum throw of the actuator to fully brake the clutch so YES your bite point will raise and pedal travel will be longer. BUT you won`t trash your gearbox and knacker your synchros. The actuator is on top of the bell housing and easy to find. When you press it you can see the fluid rise in the reservoir. Extend the pedal pushrod until you cant move the actuator then back it off a tiny amount at a time until you can. Lowering the bite point WILL make it worse as you are restricting the throw of the actuator.

 

Toyota and Subaru do not have mechanics with personal experience of taking things apart and fixing them. They have college trained spanner monkeys who follow flowcharts and spreadsheets. "Computer says no" just about sums it up. I have suggested to them on more than one occasion it was clutch drag but not once have they adjusted the clutch. The adjustment is there for a reason !

[remal 85]

cracking thread and will try this. But I do find the box get better once warmed up. but I get the issue with 1st to 2nd 

[GTB 53]

After 2 days driving I can confirm I have a very slick gearchange just like the brochure promised. The pedal stroke is what it is, determined by upper and lower hard stops. Lowering it by using the master cylinder pushrod is wrong. You are then surely using the back stop of the push rod as the upper hard stop which over time will surely knacker your master cylinder ? The push rod adjustment is not for this. The bite point and travel are fine for me. I am just very disappointed with Toyota that they are failing to look at the blindingly obvious and am glad that in my particular case can now stick 2 fingers up to them and say "told you so, clutch drag !" I have written to my local service centre manager as I promised him I would keep him informed of any developments. That`s WKB Toyota in Chichester. Be interesting to see if I get a reply.

[GTB 53]

I have just posted this on the other forum for clarification after a couple of questions:

 

Corrective action on a stock car (when I say stock I mean clutch and gearbox) is to follow the steps in the video link. I make no claims for any improvement but it has 100% worked for me. If you get under the dash with a mirror and torch you can see a hard stop at upper and lower limit of pedal travel. It is fixed, not adjustable, they are hard metal bracket stops. The master cylinder push rod has a threaded end and is attached to the clutch pedal. This allows adjustment of the master cylinder push rod position in relation to clutch pedal at upper limit hard stop. To slacken the locknut it is easier if you remove the white plastic grommet at lower hard stop. You can then get a spanner in there. If you wind the pushrod anti-clockwise (may need a little pressure on the clutch pedal) and start to lower the pedal you are pulling the pedal away from the hard stop and limiting the travel and thus throw of the clutch actuator at the bell housing. To counteract this you probably then have to wind in the upper limit travel switch to compensate. The switch isn`t for use as a hard stop. Winding the push rod clockwise does not lower the pedal but allows more throw at the clutch by effectively taking up the free play.

THINK OF THE THREAD ON THE PUSHROD AS THE CABLE ADJUSTER ON A CABLE OPERATED BRAKE OR CLUTCH ON A MOTORBIKE AT THE HANDLEBAR LEVER. ON A MOTORBIKE YOU ADJUST THIS TO REDUCE FREE PLAY.

Follow the steps on the video and set it accordingly. Once my pedal was back at full travel I reckon my pushrod turned about 2.5 rotations but wasn`t counting. I then backed it off per video. It is unbelievable the difference it has made. To find the actuator just follow the hydraulic line from the master cylinder to the slave. Get someone to depress the clutch you`ll see it move for clarification.

[GTB 53]

Just received this email from John at Jackson Transmissions where the info came from for this thread:

Geoff,

That’s awesome! I’m glad you found our video and found it helpful.

That is after all why we posted them.

However we may be in the market in the future with parts for your transmission.

Many of the guys state side are pushing them pretty high in power and we actually have a gearbox here now for R&D.

I can tell you there is much room for improvement! We are working with manufactures now for a strong gear set.

While it’s still early in the stages it is coming.

Thanks,

John

[Mark@Abbey M/S 235]

Is there still free play when the pedal is on it's top stop to allow fluid to be pushed back into the master cylinder reservoir?

Better to check this when the car is hot.

If there isn't any free play this could cause hassle as the clutch wears.

Good read thou. Funny that cars are all different thou.

[GTB 53]

Yes Mark, there is still free play. I have floored it in 2nd and 3rd on map 2 and no clutch slip (back end went out though). Setting it how he says allows for self adjust as clutch wears. if you over adjust it you`ll know as you won`t be able to manually push the actuator back.

[GTB 53]

One further week in and I can report I am 100% happy with my gearbox and gear selection. In 10 days I have only had 1 unacceptable crunch and that was 1st to 2nd when I hadn`t allowed it to wake up. Well happy !

[ivorh964 8]

Hi there - I know I'm a bit late to this thread, but I've only recently joined the club as have only had my GT86 for a few months (love it obviously!). The gearbox/gearchange symptoms described are very similar to my experiences so far. Gearchange seems to work best/smoothest when driving quickly above 4,000 rpm or so. Driving 'normally' (up to 3,500 to 4,000 rpm) or in slow moving traffic, requires concentration and skill, to ensure smooth progress, especially as the clutch has a very small operation range, ie. it is either on or off! I have driven several of these cars and they all seemed to have a high 'bite point' and short clutch travel, so I thought it was just me needing to get used to the nuances of this Toyota gearchange.

This brilliant post has reassured me that my gearchange can hopefully be improved somewhat!

I'll be at the Grasshopper meet this Saturday (3/9/16), so will be asking for some guidance or assistance on this topic (sorry in advance!). As this post is nearly 18 months old, are the Toyota dealerships 'up to speed' with the correct clutch adjustment process?

I was also interested to see that 'GTB' referred to WKB Toyota in Chichester - I'm staying near Chichester next week (as I'm visiting the Goodwood Revival) so might be tempted to visit or at least contact WKB, whilst I'm in the area. Otherwise, I'm in the Tunbridge Wells area.

Cheers, Ivor 

[86inIceland 0]

N-n-n-necropost!

Just wanted to chime in and tell you that I did this today on my Cosworth supercharged GT86 and it seems to have made a big difference. I was even able to do it by myself, just barely able to squeeze my hand through the engine bay to the clutch slave cylinder. In my case, I was able to twist the clutch electrical switch pretty much all the way back and twist the master cylinder rod all the way towards the cylinder, while still being able to manually push the slave cylinder and see the clutch fluid rise in the reservoir. This has extended the clutch pedal travel A LOT, which is somewhat of a downside.

Is it possible to damage the master cylinder assembly by over-extending the rod travel?

Thanks GTB! I'll try to remember to report back in a week or so.

[86inIceland 0]

Reporting back. This hasn't eliminated the problem, but it's made it a little better. This, in combination with the Subaru slave cylinder swap and thinner/better gearbox oil, might be the solution.