Cold transmission won't shift
05-11-2016, 07:12 PM
#1
3rd Gear
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Cold transmission won't shift
When I start my 1990 ZR-1 after it has sat for a while, I can't shift the transmission at all. If I turn the car off, I can shift into gear and restart the car. After the car runs for several minutes, the transmission warms up and shifts fine. Ideas? Fixes?
05-11-2016, 07:17 PM
#2
How long has it been since the clutch master has been checked for fluid? How long has it been since the transmission lubricant was checked/changed. How does the clutch feel and the car drive once in motion? Shift as expected, gear clash or...................?
05-12-2016, 02:45 PM
#3
3rd Gear
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good. Shifts smoothly after it's warm. That's what's driving me crazy.
Thanx
05-12-2016, 08:04 PM
#4
Race Director
I tend to agree with WVZR-1. Where does the clutch release if you start it in gear? Can you start it in gear? I remember years ago one winter in IOWA I had to back the car into the driveway and leave it in first gear. It was so cold the gear oil wouldn't let the transmission shift until it warmed up (68 Road Runner 4spd). I doubt that is your problem.
05-12-2016, 10:23 PM
#5
Team Owner
Pro Mechanic
Your clutch isn't releasing when cold. You need to figure out why. It's MOST likely, as hydraulic problem. To that end, how does the clutch "feel", cold vs. warm? What ZR1fred said: "Where does the clutch release if you start it in gear?" -or begin to engage?
05-13-2016, 10:31 PM
#7
Team Owner
Pro Mechanic
As your foot comes up from the floor, engagement should begin at about 1/2 to 2/3 of the way UP. IOW, at least 1/2 of the travel from the floor shouldn't do anything, as far as engaging the clutch. It SOUNDS like yours starts to engage (not release) about 1/4 of the way up, from the floor. That is not right. You have air in the system, or a mechanical issue w/the fork, pivot or clutch itself. Since the problem is only present when cold, that is incredibly symptomatic of low clutch fluid; you suck air from the res when cold, have a soft/low pedal. Then as it warms, the fluid expands and your pedal comes back. I've seen it many a time.
05-14-2016, 06:40 AM
#8
Melting Slicks
As your foot comes up from the floor, engagement should begin at about 1/2 to 2/3 of the way UP. IOW, at least 1/2 of the travel from the floor shouldn't do anything, as far as engaging the clutch. It SOUNDS like yours starts to engage (not release) about 1/4 of the way up, from the floor. That is not right. You have air in the system, or a mechanical issue w/the fork, pivot or clutch itself. Since the problem is only present when cold, that is incredibly symptomatic of low clutch fluid; you suck air from the res when cold, have a soft/low pedal. Then as it warms, the fluid expands and your pedal comes back. I've seen it many a time.
Marty