Looking to see if anyone has had the same problem or can shed some light on my issue with an Exedy Twin SD that's been in my JDM VIII for about two years/20,000 miles. It's had a few launches and trackdays during that time, but nothing outlandish and not immediately before the problem started.

In the months leading up to the start of the problem, I changed the gear selector mount bushes for alloy inserts and I also changed the gear selector cable bushes (at the gearbox end) for brass bushes. I also changed the front lower engine mount bush for a Powerflex polyurethane bush.

Symptoms are:-

- difficult to select gears, especially 1st from neutral and reverse. Before the gear selection was smooth, although selecting 1st or Reverse from cold was sometimes a bit stiff. 1st and Rev from a stop can feel like they're locking you out and the higher gears are difficult to select even at reasonable rpm.

- The gearbox doesn't protest audibly (inside the cabin) whilst selecting gear (no graunching or grinding), it's just very difficult to select gears at times (especially 1st and Reverse from neutral).

- It almost feels as though at times the gears aren't in the right place when trying to select them. Sometimes to select 1st I have to actually push in between where I would expect 1st and 3rd to be to get 1st, and then it doesn't feel like the gear is fully engaged (gear stick feels like it isn't pushed far enough into gear and might pop out at any moment).

- The problem didn't seem to improve much after having driven the car and warmed up the oils, but rarely the change is silky smooth even into 1st from 2nd etc.

- Exedy twin has gone from being relatively quiet to make a noticeable "coffee grinder" noise when clutch pedal is depressed.

- The gear change is extremely slick and positive when the engine is turned off. I can select any gear with ease.

Solutions tried:

- Professional bleed of clutch system and replacement of hydraulic clutch line.

- Looked for leaks (none found) and fluid in reservoir is at a consistent level.

- checked slave cylinder rod moving properly in accordance with clutch pedal movement.

- changed the gearbox oil to Fuchs Titan gear oil.


So, if you've managed to read through all of that, do you have any idea what the problem might be, and if so, a potential solution?

 

BTTT for an update and another cry for help.

The noisy clutch led me to believe that was the problem area (possibly throw out bearing/retainer clip issue?), but I tried starting the car in 1st gear with the clutch down last night and the car didn't move at all, it started just like it does when out of gear and clutch down. This suggests to me that the clutch is disengaging the transmission properly?

The clutch pedal feel is normal, as is the bite point, but I have previously adjusted the push rod on the pedal as high as it will go to try to resolve the problem and it seemed to improve the symptoms a little. If the clutch push rod were in its normal position, the engagement would be very low, possibly below the bottom of the clutch pedal travel.

I also sat with the car in neutral and the engine running and tried engaging and disengaging the clutch, there was no change in engine note or the rpm that the car idled at.

I'm really confused now, as the notchy gears (especially 1st and reverse from neutral) only when the engine is running and the noisy clutch would seem to suggest an issue with the clutch, but the lack of movement when starting the car in gear with the clutch down suggests the clutch is disengaging the transmission properly and the noise is simply rattly/worn plates.

The gears will engage very well with the engine off, but are very notchy with it on, how can that not be a clutch problem?

I have previously fitted brass bushes in the selector cable eyes (at the gearbox end), these were greased at the time, but I hear these can cause a notchy change if not properly lubed. I also loosened and then retightened the bracket holding the gear selector cables on the gearbox. However, I haven't checked these yet as the gear selection with the engine off is very good so I would imagine these can't be the problem?

 

You may need to rebuild your clutch

 

Thanks, I realise that's a possibility, but I'm trying to pinpoint the problem before handing it over to a garage to fix.

I don't want to be without the car for weeks whilst they attempt to diagnose the problem, nor to chuck money their way until they try one thing after another until the find the problem.

I'm just drawing blanks because it seems like the clutch is working at least to disengage the transmission on engine start, but whilst gear selection is fine with the engine off, it's extremely notchy with the engine on.

 

I sometime have this problem. I have about 4k miles on my exedy twin hd

 

My Exedy Twin SD started doing the same thing about a year ago.

I've done about 40-50 launches at the drag strip and about 100+ launches at autox's. Now..I know that it was always hard to get into reverse since day one. So..I don't know if it was install error. Me and a friend installed it without dropping down the subframe, so in squeezing the 6-speed in, we might have kinked the clutch pack. Dunno...either way..what's done is done. My friend's Twin exedy HD has more launches than mine and it doesn't exhibit this problem.

The intermediate disk/plates are warped, so they are causing the clutch disc to drag on the flywheel/pressure plate. You will notice it while trying to get into 1st and reverse because they are the easiest gears to spin.

First thing is first, take those metal/poly bushings out. Stick with the rubber bushings on the 6-speed tranny. I tried bushings and it made it worse. The base shifter bushings limited the side-to-side movement needed to get into 1st/2nd and reverse.

I've learned to live with the problem. I usually just put it in 3rd gear first (clutch out) and then swing it into either 1st gear or reverse. After awhile, you get used to it. I don't have problems getting into any other gears and actually love the hell out of it's shifting action. No high rpm lockouts and shifts quick. Eventually after I burn this clutch up, I will replace it. Maybe rebuild it into a triple disc.

 

This was my 6 speed fix, dunno if it has similar linkage in a 5 speed

https://www.evolutionm.net/forums/ev...hlight=dxbtune

 

What I put in bold means that your clutch is dragging aka not fully disengaging. There are a few things that could cause this. I suggest;

Adjusting the clutch pedal out
Bleeding the slave cyl
-if that doesn't help you may either have
warped or worn clutch discs or plates
damaged input shaft

 

the transmission side floater plate is warped preventing your clutch from releasing. Fix it or it will kill your syncros and then you'll have to rebuild your transmission in addition to replacing your clutch.

BTW the part that is warped isn't normally part of the rebuild kit.

 

Sounds to me that your cable has come out of the holding clip on the shifter housing. Probably happened when you put in the bushings. Just make sure they are secured and click in place.

 

Excellent, thanks for the link and for taking the time to post up the original thread. My car has a 6 speed box, so this is something else to try.

 

If the clutch were dragging, wouldn't you be able to notice it when starting the car in gear with the clutch pedal down?

Even if the car doesn't move, surely they'd be a dip in rpm and/or engine note?

 

Thanks, I haven't checked these yet as it gets dark here before I get home from work and I was out all last weekend. I'd previously assumed that because the gear changes are like butter with the engine off that it couldn't be a linkages/selector problem, but I'll double check them as soon as I get a chance.

 

Thanks, this is definitely top of the priority list to get done, it's just I would like to narrow down the options to save time and money at the garage.

Would the car start in gear with the clutch down without moving or any noticeable dip in rpm/engine note if floater plate is warped and the clutch not releasing properly?

 

It sounds like you need to adjust your clutch pedal out ..