Grinding Gears
 

I've recently fitted a 35k or so MK2.5 gearbox to my MK1 car (which has a MK2.5 engine).

My MK1 box was very notchy, noisy, grumbly and well pretty knackered.

Now the new box is fitted, it's much better, BUT it's still not silky smooth. It'll still baulk with 1-2 shifts, and in general isn't nice to use - unlike my dads 150+k MK1.

Oil used in the box is Amsoil 75w90

I've bled the system till I'm blue in the face, (I got a face full of fluid for my trouble too), the slave cylinder is the 2nd on this car, I don't loose any clutch fluid.

What else could be wrong?

I've tried the pedal adjustment, to the point where the bite was right at the top of the pedal, no difference whatsoever

This evening in a fit of inspiration/desperation, myself and my dad placed 2 washers in front of the slave cylinder. Effectively extending it's movement.

Shift quality is loads better, not perfect, but a big improvement.

I've since replaced the washers with something a bit more secure and longer, but the added length has provided zero improvement.

So can you adjust the slave? Are there different length rods available? Is something else fucked? Master? Another slave!?!

I inspected the clutch surface 2 weeks ago when replacing the box, there's nothing wrong with the clutch, and it is fitted the correct way around.

Help me fix this as it's driving me up the wall. I hate changing gear as it feels horrible, and it's supposed to be one of the best parts of the car.

Leaking slave, leaking master?
Broken fork?
Worn clutch/TOB?

Oh, and a MK2 gearbox is full of win in an NA. Love mine, much better.

Slave is the 2nd one on the car in the time I've owned it. I'm not loosing any fluid whatsoever, so I really don't think that's the issue.

Would a master leaking show it's self as fluid loss?

Clutch looked perfect when I pulled the engine/box to replace the box, same with the TOB.

Fork I used the one in the MK2 box, so can't be that as it did the same on the MK1 box/fork.

Are we talking 5 or 6 speed 'box?

The 6 is known to be a less "nice" shifting gearbox.

Sorry, it's a 5 speed box.

This box shifts more nicely than my old MK1 box, but no-where near as nice as my dads MK1 box

It's the gear oil. Is this "Severe Gear"? You're using one of the most "EP5 rich" oils made in a transmission that cannot handle EP5 friction modifiers. Drain the oil, fill it with Penzoil Synchromesh for a few days, consider "rinse and repeat" if it's still shifting poorly, then switch to AMSoil MTG.

Assuming the transmission shifted fine before you swapped, this will fix it. I see this shit all the time. People don't understand that EP5 lubes are for ring gears and differentials. Precise copper synchronizers change the game.

I'm using an Oil you yourself and Savington recommended on this site!

The oil I'm using is AMsoil MTG...

Good, but it's not a 75w90. How many miles do you have on the current box? If it had the wrong oil in it, a few miles may help improve things, but usually it only fixes "scratchy synchronizers". Is there any oil in the turret?

Hustler, I liked the site I bought the oil from. It's the exact same stuff you recommend, 75w90 etc etc

I'd love it to 'just' be wrong oil mind...

You said the washers on the slave helped, that still makes it look like a hydraulic issue.

Agreed, but I'm not loosing fluid?

I don't think the clutch is dragging, but is there any tests I can do?

Air in system? Adjust pedal stroke? Leaking internally? Change master?

Your master cylinder could bleed off internally. I just did mine. The inside was pitted and it would blow past the seals. It got so bad that the clutch would engage on it's own with the pedal fully depressed.

Pump the clutch pedal 5 or 10 times and see if it builds pedal pressure and engages any smoother. That's what I would do and it would make it so I could get it in gear. It will bleed back off pretty quick if it's bad, though.

It says 75w90 on the bottle, you twit.

I think I have your solution, shifter bushing kit, my 95 w/ 195k miles was popping from 1st to 2nd, going to 5th had an awkward gate feeling, and going from 2nd to 3rd sometimes would grind and kick out. Also the shifter wiggled a bit in each gear about a quarter inch in every direction and going to reverse took quite a bit of effort, usually I had to pump the clutch a few times when the tranny was cold to get it in.

I bought these items for my 95.
http://www.finishlineperformance.com...0&cat=0&page=1
http://www.finishlineperformance.com...cat=320&page=3
http://www.finishlineperformance.com...cat=320&page=3

and now all is well, the gear box that was notchy, had all the symptoms above, etc now feels like new and feels as smooth as butter, notchiness is pretty much non-existant and the gates feel very clear and predictable. On visual inspection the bushings looked okay on the shifter, but after replacing everything, i could tell it obviously wasn't the case.

Does nobody else see a problem with this? If you did what I think you did, that's like resting your foot on the clutch pedal while driving around.

Just use the factory adjustment on the clutch pedal itself. I'd be less worried about dragging the clutch and more worried about breaking the pressure plate.

So does Redline MT90, feag.

I tried adjusting the clutch pedal, see the OP, it made zero difference. yet adding an extension to the clutch arm did.

I'm not saying what I've done is right, but doing that helped. I'd rather find out the actual issue and fix it properly.

FWIW I'm not actually convinced the clutch is dragging, There's no rpm drop when I put the car in gear (or an increase in idle valve DC to compensate), plus the bite from the clutch is at the midpoint of the pedal travel, surely if it was dragging the bit would be pretty much at the floor?

So am I using the wrong oil or the right oil?

I really appreciate the response, but I don't think that will help me? I have a 2003 box now. the 1st link I can only really use the nylon cup, and that is only a few months old (nicked from my old box). I also have a new lower boot fitted.

I'm guessing MC if you don't lose fluid but still have hydraulic issues.