George_Achter

So here my problem,

I recently had the infamous syncro key problem in fourth gear . So I had my friend/mechanic fix the problem as well (new shift fork , 3-4 syncro keys, slave and master cylinder). Later on my 3rd gear went out. We put a new 3rd gear and syncro in, as well as installed a monster stage 2 clutch.

So I'll get to the point , whenever I down shift into 3rd gear it will grind with any past 2.5k some times and when I try to rev match it too.

Any thoughts ?

All other gears are fine upshifting and downahifting . upshifting in 3rd gear feels fine, only feels slightly different past 3.5k.

Hoping its not the syncro...

George_Achter

Clutch is fully decompressed as well when this happens.

Bill Curlee

What is the condition of your CLUTCH? Does it FULLY disengage the drive line when you have it fully depressed???


Recommendation: Jack the rear of the car off the ground and set on jack stands. Start the engine, put in first gear and have some one fully depress the clutch and see if the rear wheels STOP turning. If the clutch does not fully disengage the drive line from the engine and the rear wheels are still being driven, you will have a difficult time shifting if the synchros are not 100%

2. What ATF do you have in the MN6?

George_Achter

Clutch only has 360miles on it. Still breaking it in with easy driving, nothing aggressive. Yes, it seems to be operating properly. I've had no issues with any other gear. Only the occasional lock out of 1st, which is usually remedied by throwing it into 2nd or by backing out and trying again(no grind). Other than that though I can downshift and upshift into any other gear w/o problem at this point. 3rd is the only one I have problems down shifting into past 2.5k (usually where the problem pops up) and the couple times I upshifted into 3rd past 3k rpm from 2nd it felt funny going in( not like the other gears where it pops in)

As for atf I do not know, just messaged my mechanic to asking him what he put In.

Forgot to mention too that blocked ring is new too.
Just kind of confused cause practically 3rd gear is brand new.

George_Achter

Update: my mechanic said he put in "Valvoline max. Dex I think"

Bill Curlee

If you raise the rear and depress the clutch, then REV the engine towards red line, does that cause the wheels to spin?

There are several things that can cause that to happen:

1. BAD / DAMAGED pilot bearing
2. Warped clutch disk (caused during installation by letting the drive train hang when the TT was being mated to the bell housing.)

Do that test and see what happens

You can also rev it on flat level ground with the clutch fully depressed and see if it try's to roll FORWARD. It shouldn't.

Bill

George_Achter

I have yet to test the the clutch like you reccomended. I will try that tonight. If it helps the pilot bearing is brand new from the monster kit.

But if it was a warped clutch disk would it be effecting other gears aswell? Not just 3rd?

Bill Curlee

When my brand new TRANSZILLA T60/60 MN12 converted trans was first installed,, I too had a 3RD gear grind when normally the trans engine/drive train was cold and,, during HIGH RPM UP - SHIFTS. Only 3RD Gear!! NO other gear would grind!

Just properly bleeding the clutch and properly adjusting the release of the clutch disk (making the master cyl rod longer) totally fixed that issue!

YES,, my rear wheels continued to rotate (clutch fully depressed) until I properly adjusted master cylinder.

I just tested it last Sunday (car is in the air for some exhaust work and a PFADT Differential mount install! )

It was 30 Degs outside and I cranked it up, depressed the clutch and revved it. ZERO wheel spin.

See if you have no creep and wheel spin in all those conditions.

NOTE. A small bit of low torque rear wheel spin (easily stopped by hand) when the drive train is cold shouldn't be of much concern. When it fully warmed, clutch depressed, there shouldn't be any movement.

Bill

Bill

George_Achter

Thanks for the quick responses!
Again my problem is only on the downshifts currently. (Don't know if that differs from your upshift problem or if it stems from the same problem?)

So your saying (just to clarify) bleed the hydraulic system again and check the master cylinder rod length and adjust accordingly ?

Bill Curlee

Thats what I would do..

NOTE! If you bleed and adjust and that makes a big difference and after a period of time it starts giving you issues again, try bleeding it first and see if you have any air in the system. If you do, that means your are getting AIR in the system from somewhere.

BC