Transmission Question
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Joined: Jun 2009
Posts: 72
Likes: 4
From: New Iberia Louisiana
Transmission Question
I am running a ZZ3 engine and ST-10 trans. I've put about 1000 miles on the car since I got it, with no issues. Installed a new carb, was road testing, hot rodding, but not abusive, no power shifting. Transition to secondaries acts like a passing gear in an auto trans. Making adjustments to secondary flap. After about 10-15 miles, when I got home the shift lever was very stiff, could hardly change gears. The only way I could get into reverse was to kill the engine. Much grinding with engine running. Clutch feels OK. Trans fluid level good. Today I duplicated the drive and had no problem. Any ideas?
Race Director
Joined: Jan 2003
Posts: 17,721
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From: Central Arkansas
Sounds like you are loosing your clutch gap when the drivetrain is warm and the clutch is pushed in for some reason. Does your clutch normally start to grab right off the floor when you start to release it? Seems I’ve read of this occurring when the engine/drivetrain warms up before but I don’t recall the cause. Maybe it was with hydraulic systems which would not apply in this case. If you have enough free play at the top of your pedal throw I would at least try reducing that to get the release point further off the floor.
I would also check your clutch pedal for a bad weld at the shaft. Does it have any unusual amount of side to side play if you move the pedal by hand from side to side? When failing the pedal will often deflect off to the side when pushed in and that interferes with the clutch being able to fully disengage. Could be it’s in the early stage of failing and working a little erratic..
I would also check your clutch pedal for a bad weld at the shaft. Does it have any unusual amount of side to side play if you move the pedal by hand from side to side? When failing the pedal will often deflect off to the side when pushed in and that interferes with the clutch being able to fully disengage. Could be it’s in the early stage of failing and working a little erratic..
Le Mans Master
Joined: Sep 2008
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From: Lake Minnetonka, Mn
2018 C1 of Year Finalist
I assume this is not a hydraulic clutch? "Much grinding when the engine was running". Grinding when attempting to shift going down the road, and/or grinding when trying to place it into gear at idle?
Instructor
Joined: Aug 2020
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If you are not running a hydraulic clutch (In which an air bubble can expand and contract, although that would usually cause the exact opposite problem), Then it has to be mechanical.
Piece of a broken hub spring moving around is my first guess, because I've seen that a few times. Could be a loose section of clutch lining, throwout bearing or linkage starting to come apart.
If it was a one time occurrence, maybe it shed the offending debris. I'd start with the pedal and z-bar assembly first, just because it's easiest.
Piece of a broken hub spring moving around is my first guess, because I've seen that a few times. Could be a loose section of clutch lining, throwout bearing or linkage starting to come apart.
If it was a one time occurrence, maybe it shed the offending debris. I'd start with the pedal and z-bar assembly first, just because it's easiest.
Thread Starter
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Joined: Jun 2009
Posts: 72
Likes: 4
From: New Iberia Louisiana
Update: Seems too good to be true, but I changed out the transmission oil and the problem disappeared. Richmond Gear, who manufactures ST-10s recommended 80w-90, conventional,. GL-4 oil. Hard item to find around town, had to order from Amazon, but (fingers crossed), that was the cure.
Thread Starter
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Joined: Jun 2009
Posts: 72
Likes: 4
From: New Iberia Louisiana
Sorry it took me so long to respond. The problem was grinding when moving from neutral to any gear when stopped after the car was warmed up. Since I changed the oil, I have not had any problems. I have put at least 500 miles own the car since that time.
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