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Transmission Shudder First Gear Only

Old Sep 19, 2018 | 06:23 PM
  #1  
sjwarden's Avatar
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Transmission Shudder First Gear Only

I posted this in the general first gen technical section in error, so posting it here now. Hoping someone can help me out.

Hoping someone can help me diagnose this issue. My 1985 GS has developed a very bad transmission shudder in first gear only. From a stop, when I put the car in gear and start to let the clutch pedal out and apply gas to get going the transmission shudders violently. The only thing that prevents this shudder is to give the engine a ton of revs, like 3-4000, and let the clutch pedal out relatively quickly. If I do that I still get a slight shudder but not bad. I also chirp the tires about half the time. If I don't do this, the shudder is so bad it shakes the entire car and I have to quickly put the clutch pedal back in for fear of breaking a mount. This happens right away and does not appear to be temperature dependent. I have been under the car frequently and can see no leaks of any kind. The slave cylinder appears dry and is not leaking.

Starting from a stop in second gear is fine. Just as you would expect from a second gear start, a little slow but smooth and no drama. All other gears are fine. First gear is fine as long as I am already rolling, even a little.

At first I thought I had developed some bad driving habit and I was not working the clutch correctly, but that is not the case, and the symptoms are getting worse.

The car has less than 40K miles on it, I use royal purple transmission fluid, and the shift action is excellent. The car is otherwise a gem, and runs perfectly.

Am I looking at a new clutch here, or worse? Flywheel hot spot maybe? But those would not explain second gear being just fine would they?

Any insight and advice is appreciated before I begin taking this car apart.
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Old Sep 20, 2018 | 12:10 AM
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Originally Posted by sjwarden
Am I looking at a new clutch here, or worse? Flywheel hot spot maybe?
could be on one or the other, or both.

But those would not explain second gear being just fine would they?
well, since we don't start off in second gear, shifting thru the gears will be fine. it's just starting from a stand still, in first gear.

and there was nothing wrong with posting this question in the first gen section.

Last edited by rxtasy3; Sep 20, 2018 at 12:12 AM.
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Old Sep 20, 2018 | 04:02 AM
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1st suspect would be the flywheel having some run-out and needing a resurface. If you haven't already, I'd also bite the bullet and replace the clutch and PP at the same time...making sure everything is mated completely and torqued to spec. I think it's common to only see things like that in 1st gear as the application of torque is greatest.
I suppose an outside chance that the disc is partially contaminated (usually from oil from rear main) and slipping just in first gear for the same reason.

Last edited by Sgtblue; Sep 20, 2018 at 11:12 AM.
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