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Old 11-02-2015, 02:08 PM   #1
michaely31
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trans grind into reverse

any ideas why my manual transmission on my 72 gmc is grinding when going into reverse

fluid levels?
clutch?
operator error (I haven't had this problem before)?

thanks

-Michael
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Old 11-02-2015, 02:13 PM   #2
michael bustamante
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Re: trans grind into reverse

if i dont push my clutch into the floor panel, my reverse will grind too
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Old 11-02-2015, 02:37 PM   #3
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Re: trans grind into reverse

My transmission does the same thing. My clutch is also in adjustment, so I've found to just double clutch into reverse and it does not grind. I know probably not the best solution but the time being thats what works for me.
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Old 11-02-2015, 03:13 PM   #4
67ChevyRedneck
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Re: trans grind into reverse

There's a shift pattern that helps too, but it's been so long since I had my 3 speed.

Maybe 1st, then R? Meaning with the clutch in, shift to 1st first, then into R and it helps.
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Old 11-02-2015, 03:16 PM   #5
michaely31
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Re: trans grind into reverse

thanks, I never considered that
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Old 11-02-2015, 03:19 PM   #6
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Re: trans grind into reverse

I shift mine into second and then reverse, stopped the grinding
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Old 11-02-2015, 03:24 PM   #7
joecaruso
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Re: trans grind into reverse

Quote:
Originally Posted by 67ChevyRedneck View Post
There's a shift pattern that helps too, but it's been so long since I had my 3 speed.

Maybe 1st, then R? Meaning with the clutch in, shift to 1st first, then into R and it helps.
Yes that is what I meant to say too. Do not know why I said I double clutch. I do in fact go into first then up to reverse in on motion which eliminates any grinding. I was told by someone along the line that this was due to a non synchronized reverse gear, but whether or not that is the cause someone else would have to confirm.
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Old 11-02-2015, 03:25 PM   #8
67ChevyRedneck
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Re: trans grind into reverse

I drove with my 3 spd for about 6 years before I put a 700R in, around 2002? So, I'm a little fuzzy on the shift combo!

Try 'em all and see if any work for you.
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Old 11-02-2015, 07:42 PM   #9
Bigdav160
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Re: trans grind into reverse

Reverse is not synchronized in these old transmissions.
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Old 11-04-2015, 01:29 PM   #10
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Re: trans grind into reverse

I find I just need to hold the clutch in for a few seconds before I shove it in reverse and no grinding.
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Old 11-04-2015, 08:39 PM   #11
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Re: trans grind into reverse

the clutch is not disengaging completely and allowing the input shaft to spin...a syncronized gear is much more forgiving to this condition...the clutch might need to be adjusted,there could be oil or grease on the disc causing it to stick to the flywheel and/or pressure plate,a bad pressure plate not releasing evenly,a disc with a piece of friction material hanging off and dragging, or a worn or dry input shaft bushing in the back of the crankshaft could all cause this...sticking it in a syncro gear to get it to stop spinning then quick stuffing it into reverse will make it driveable but you're not doing your tranny any favors
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