 Transmission noise in reverse |
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| patssle |
 Jul 17 2015, 08:19 PM
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#1
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Senior Member  Group: Members Posts: 981 Joined: 28-August 09 From: Houston, TX Member No.: 10,741 Region Association: None  |
Car is making pretty loud noise when reversing and then throwing in the clutch. Works absolutely fine in all forward gears and no problems with 1st gear. Shifting does not grind the gears at all. It has worked fine for several years since I had the transmission rebuilt by a reputable Porsche mechanic. It seemed to start after I accidently grinded reverse.
I've taken the rear off and have looked at the bearings and reverse gear - everything looks ok. Is there anything I can do to verify the bearings are okay? But looking at the drawing diagram - doesn't the reverse idler gear always turn regardless of what gear you're in? Could it be the shifting gear for 1st/reverse - but then wouldn't it make the noise in 1st too? Sees as soon as I yank the shifter out of reverse the noise stops.     |
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| patssle |
Jul 18 2015, 07:49 AM
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#2
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Senior Member Group: Members Posts: 981 Joined: 28-August 09 From: Houston, TX Member No.: 10,741 Region Association: None |
Bump!
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| Mike Bellis |
Jul 18 2015, 07:53 AM
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#3
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None 
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Don't drive in reverse. (IMG:style_emoticons/default/poke.gif)
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| patssle |
Jul 18 2015, 01:58 PM
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#4
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Senior Member Group: Members Posts: 981 Joined: 28-August 09 From: Houston, TX Member No.: 10,741 Region Association: None |
Yeah it's been like this since last year...try to avoid reverse when I can. But if it's something that can effect more than reverse I need to figure it out.
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| oldie914 |
Jul 19 2015, 07:03 AM
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#5
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Member Group: Members Posts: 102 Joined: 2-May 10 From: Germany Member No.: 11,680 Region Association: None |
Since it only makes noise when reverse gear is engaged, sounds like the reverse gear teeth are rough. Try replacing the reverse gear idler and the 1st/reverse shift sleeve.
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| patssle |
Jul 25 2015, 12:07 PM
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#6
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Senior Member Group: Members Posts: 981 Joined: 28-August 09 From: Houston, TX Member No.: 10,741 Region Association: None |
Well I replaced the cage and needle bearings for reverse and it's still doing it. The idler gear and reverse/1st shifting gear don't look bad. It still sounds like this: http://www.patssle.com/trans.mp3
Are there any other transmission experts I can send a message? Haven't heard back from Evil - seems he's not online lately. Willing to send a few dollars for their consulting time! |
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| Mike Bellis |
Jul 25 2015, 04:20 PM
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#7
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None
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Something is rubbing on your reverse gear or you have had an out of adjust clutch for some time. Replace the gear as the end looks mushroomed.
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| patssle |
Jul 25 2015, 04:38 PM
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#8
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Senior Member Group: Members Posts: 981 Joined: 28-August 09 From: Houston, TX Member No.: 10,741 Region Association: None |
QUOTE(Mike Bellis @ Jul 25 2015, 02:20 PM)  Something is rubbing on your reverse gear or you have had an out of adjust clutch for some time. Replace the gear as the end looks mushroomed. I've definitely nicked reverse a couple times over the years (when going to 2nd) which would explain that. But it only makes noise when the gear is fully engaged - not in idle or any other gear. |
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| Dr Evil |
Jul 28 2015, 08:07 AM
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#9
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Send me your transmission! Group: Members Posts: 23,000 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region
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As illustrated above, you ground revers a bit. The noise is only bothersome and not an issue. Yes the idler is always moving so the bearings were fine. The reason your reverse makes noise is because of the interface between the 1/R slider and the idler. The mesh is likely not perfect, but not an issue.
I didnt get any message, sorry to have missed it. If you do replace the idler, you have to replace all of first gear. They are a matched set. Replacing the idler only will lead to noise, so back to square one. It is possible that replacing the 1/r slider may alleviate you issue. Consequently, most idlers look like that, all will have some wear due to a missed shift. How do the teeth on the 1/r slider look? Probably chewed. How do the faces on both look? You can also try taking a file and cleaning up the edges. If any mooshed metal is in the plane of interference from the slider and idler, you will get noise. If you remind me, I can take pics of a set or two from my stash. |
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