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'81 4spd - reverse shift grinding

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Old Mar 4, 2008 | 07:20 PM
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Default '81 4spd - reverse shift grinding

Can anyone tell me why my '81 has started grinding the gears when I go to shift in reverse. I have no problems and the forward gears all synchronize smoothly. In order to shift into reverse without the heavy grinding noise, I have to run through several of the forward gears first. What do I need to do? Does this represent a major problem with the transmissions. By the way, the vehicle has 50,000 original miles, I'm the second owner and it has never been raced or wrecked.
Your very informative responses will be greatly appreciated.
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Old Mar 4, 2008 | 08:04 PM
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sounds like you should start with a simple clutch adjustment. pretty simple to do with a couple of 9/16ths open end wrenches. The adjustment rod is directly underneath the master cylinder but easy to get to.
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Old Mar 4, 2008 | 08:10 PM
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Gotta agree, reverse is not synchro'd. So it sounds like a little drag.

If memory serves me right, the Manual says that in the clutch adjustment you have to wait 10-15 seconds for the tranny shafts to quit spinning.
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Old Mar 4, 2008 | 09:36 PM
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Originally Posted by Tonys96
Gotta agree, reverse is not synchro'd. So it sounds like a little drag.

If memory serves me right, the Manual says that in the clutch adjustment you have to wait 10-15 seconds for the tranny shafts to quit spinning.
... ...in the 1968 owner's manual, it recommends shifting "momentarily" to any forward gear BEFORE going to reverse.
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Old Mar 4, 2008 | 09:42 PM
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my 81 does the same exact thing! My only problem is im out of adjustment!? Im not sure if I got the wrong throwout bearing? Or the flywheel got cut 1 to many times?
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Old Mar 4, 2008 | 11:16 PM
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I've had this issue with a few of my stick shift cars. Try this: With the clutch in, shift into 1st and then into reverse. It will slow the cluster down and it will not grind going into reverse. Hope this helps.

Ooops, like Paul & Tonys96 said above. I should read the whole thread before I post!! It has been a long week already!

Last edited by blown454; Mar 4, 2008 at 11:20 PM.
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Old Mar 5, 2008 | 01:33 AM
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I always put it in first before I go to reverse, and never have a problem - even with the new transmission. After 20 or 30 years, it becomes automatic...
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Old Mar 5, 2008 | 08:11 PM
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Thanks to all you great people who responded, recommended and shared solutions. I greatly appreciate your assistance. Happy Vetting!

In my younger days I owned every engine chevy made with both Muncies and Borg Warner 4 speed trannys and I can honestly say I red lined these vehicles constantly and never have I encountered the reverse grinding I have recently noticed in my '81.

Best wishes to all.
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Old Mar 5, 2008 | 10:18 PM
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Originally Posted by bruced267
my 81 does the same exact thing! My only problem is im out of adjustment!? Im not sure if I got the wrong throwout bearing? Or the flywheel got cut 1 to many times?
...I used to have the same problem in my 1980 4spd car I used to own. When I went ahead and put a new clutch in it(many years ago), I found out that about 30% of the top of the clutch fork pivot ball stud was wore off!!! This meant that the clutch fork was further away from the pressure plate. The clutch fork could not release the clutch disc enough to keep the pressure plate completely off of it, letting it drag and constantly spin the reverse gear. A new clutch fork pivot ball stud was the cure in this instance. Car had about 87,000mi on it when I did all this to it.
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