2004 5spd with ACT 2600 Street Disc and resurfaced flywheel.
Solid buschur shift cable Bushings.

Up shifting is perfect in all gear under any load.

If I'm in 5th and downshift to 4th(no go. completely locked)
If I'm in 5th and go to Neutral then to 4th(no go. locked out)

If I go from 5TH to 3rd or Neutral to 3rd and THEN 4th(Its works perfect)

So 4th works every time up shifting but never from downshifting or from neutral.
At idle 4th goes in fine.

I checked shifter linkage=OK
I checked and adjusted Clutch pedal and tried different adjustments=OK
I checked linkage by themselves for binding=OK
Without the cables Trans shifts in all gears by hand on the unit itself=OK


Disclamer but dont make this the obvious answer...

The owner had clutch master clutch before, he did not like it so he just swapped to ACT(80-100 miles ago)
He claims he never noticed an issue with the CM clutch BUT BUT he rarely downshifts in that manner

SOOOO He either never knew about the pre existing 4th problem with clutch master

or

The ACT is to blame????


THANK YOU!

 

What fluid are you running in the trans?

 

mt90

 

Bump

 

I have this exact issue from a used trans I bought from someone here on EvoM... in fact soon ill be pulling it out and apart. Im leaning twords a synchro issue.

 

id say a bad synchro. if it was gear oil it would probably be garbage to go into any gear.. although if u mean mt90 as in redline. i think redline products arent to great due to the numbers of complaints ive seen on these forums about transfer cases taking a **** due to that oil. after you fix the trans id go with oem fluid

 

Same here. 1st time it happened I was using redline, so I switched to AMSOil which didn't change a thing. Now after about 2000 more miles 4th gear locked out during downshifts and upshifts. The only way I was able to get it into gear was to rev match. I rebuild the transmission and again I was back in business. Drove the car about 5000 miles when 4th gear started locking out on downshift again. So here I am again. rev matching 4th on the downshift. What do we do to fix this? Who can I trust to rebuild the transmission and not leave me wishing I hadn't chosen them?

 

Same issue in my MR on a competition clutch and resurface flywheel. This is just more recognition of bad news.... I was thinking about having TRE doing the 6 speed refinish on it.

 

ACT is known for this nonsense, go back to stock or get exedy twin HD

 

^This, and any given previous owner is going to say "I never had any problems out of it", whatever may be the case. I just had my transmission rebuilt because the ACT HDSS that was in it caused all the dog/synchro teeth to get chewed up because the clutch wasn't properly/completely disengaging, which ultimately led to the notchy shifts and lockout issues.

 

+1

 

if not a synchro going bad then possibly the dog teeth on your 4th gear might be going bad. Might sound weird but what shift knob are you running, reason I ask when swapped my shift knob to an ams, the shifts felt more crisp. But if i had to guess id say either synchro or the dog teeth, unfortunately the trans will have to be cracked open just in case. Sorry to hear it man. My act clutch gave me a few issues, but my current one has been in for over 35k with no issues and a few track days. Might not make sense now but what helps with engagement, is swap your clutch lines to SS upper and lower lines if and when you do pull the trans out, I had that done when my new clutch went in and engagement and pedal stays consistent.

 

I've never had an ACT clutch and I'm still having this problem.