Hey guys, been searching around but didn't really find a definite answer. It seems as though a lot of people encounter this problem.

My completely stock 150,000 mile '95 Civic LX 5spd shudders when starting in 1st gear. It only happens when the car is cold. Like early morning starts or being parked for 6-8 hours etc.

When starting in 1st gear, I encounter violent shuddering vibration. It lasts for maybe a second or two , then it's gone. It only does this in 1st gear. All other gears are fine as well as reverse. Again, this only happens when the car is cold. Once warmed up, the car drives fine and 1st gear take-offs are fine.

My clutch seems okay. I'm not sensing any slip and gears hold fine (highway and city). It's just 1st gear starts when cold.

Has anybody found out what the main cause of this is?

 

It is possible that you may have a rear main leak or trans leak that is just enouph to have gotten onto the clutch disc or someone put too much grease on the input splines and it got on the disc. I am thinking this because it sounds heat related. Try pulling the inspection cover to see if there are any little signs of contamination on the clutch.
Other than that, the only other idea I have is that the flywheel may not have be properly resurfaced if and when the clutch had been replaced. But usually this starts right of the the get go when the car is put back together.

 

Same thing happened on my 96, ended up the clutch was on its way out (but wasn't slipping but friction material was near end of life). New clutch kit fixed the issue.