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#1
03-05-2018, 08:54 AM
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717.400 Getrag 5-speed idle noise...
I've lived with it for a few years now...you know, that loud noisy rattle at engine idle that goes away when the clutch pedal is depressed? Attributable to a bad input shaft bearing, or perhaps a inadequate shimming of the reverse idler shaft, it's definitely noticeable (especially compared to my other 300D euro with the same tranny that's quiet as a mouse).
Well I might have found an easy fix for this noise. I had the transmission out on the driveway pavement in the course of changing out a bad throw-out bearing. With the tranny out, I figured that it would be a good time to drain and refill the transmission fluid. As you know the fill hole is on the side of the transmission, so its kind of hard to overfill the transmission case since surplus fluid would run out the fill hole. Well I got the bright idea to overfill the case slightly by rolling the tranny on its side so that the fill hole was at the 10 o'clock position instead of at 9 o'clock. The goal was to get lubrication to the area of the tranny that was making the noise, even if it meant overfilling slightly. I'm thinking the fluid level is about a quarter of an inch above normal. This tranny has 474,910 kilometers on it, so what the heck? (When the tranny/engine on this beast finally dies this car will revert to parts-car status for the other one). Long story short, that loud aggravating noise at idle emanating from this 5-speeed Getrag is gone. I don't know if the slight overfill did the trick, or it was the fluid type (cheap Walmart "high mileage" ATF). So far so good. I will update if the noise comes back... 
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#2
03-05-2018, 09:26 AM
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Nice, that is also how ford 3/4-1 ton truck guys with zf5 cure their getrag rattle: fill with one extra quart of atf through the shifter hole.
On my former 190Dt with 717.411, I drained the fluid(which must've been some high end synthetic like redline Mtl or 75w90ns as the shifting was great even cold) and refilled with normal dex 3 and my idle rattle was worse, even when cold. My former fluid didn't let it rattle noticeably until it was stinking hot... Then again I only filled it up to the fill plug as it was installed in the car
__________________
97 e300d, 78 300Dt, 95 E300d, 94 E320 estate
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#3
09-07-2018, 07:04 AM
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Thank you for this tip - one of the best I've had! For ages I've put up with the rattle and everyone says there's nothing that can be done without a total strip down etc.
Well, it worked for me too. Mine has 250K miles on it. I overfilled it with the tranny in position and simply jacked the car up as high as I could on the one side and got it on an axle stand. Got about an extra pint of Mobil 1 (only the best for this rare gearbox!) in. Noise gone.
__________________
Cars owned: W108 diesel, hot rod Frogeye Sprite, unrestored pre war Hillman Minx.
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#4
09-07-2018, 08:46 AM
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Overfilling adds some drag to the gearbox to quiet things down.
Overfill might not be such a good idea and can cause durability problems while driving due to aerated oil. Aerated oil = reduced lubrication. Another issue is increased fill levels can increase oil temps / decrease life of the oil. Gear rattle occurs when the gears are worn ( increased backlash ), engine is running rougher than new and / or the center springs in the clutch disc are too stiff. The noise isn't harmful since there isn't any load. I'd move towards a thicker oil before overfilling, assuming the recommended factory fill level is correct. ( It probably is .) For thicker oil I'd investigate high zinc motor oil ( used on some other brands ) or industrial lubricants where many viscosities are available. Just be sure to use something compatible with brass ( syncro rings , thrust washers ) as extreme pressure lubes ( differential gear lube ) contain sulfur can leach zinc from the brass. See what Gale Banks has to say about fluid levels in a differential but it will apply to any flooded lube gear system. This is part 1, part 2 has not been posted yet. Also dig around on the net to see what Gale Banks has to say about diesel smoke and power. Do Diff Covers Work or Are They Just Bling? Part 1 https://www.youtube.com/watch?v=n4DQ-jzKQRw
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#5
09-10-2018, 10:37 PM
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Part 2 of the diff cover / fluid level test. ( there will be a part 3 later )
https://www.youtube.com/watch?v=09JsDorR6tw
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#6
09-14-2018, 08:10 PM
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Not part 3 yet, just a side bar. I'm surprised how much the oil foams up.
What's going on behind your stock diff cover? https://www.youtube.com/watch?v=9-yG3D3JBRs
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#7
10-05-2018, 07:07 PM
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#8
10-06-2018, 08:52 AM
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I don't disagree with you or Gale Banks. However I have not changed the geometry of my transmission case like Banks did by installing a flat plate cover on the differential that he tested. Therefore I feel confident that fluid is getting to every area that needs it.
If Banks were to put this old diesel on the lift (that is if it didn't vibrate off and crush him) and had a window into an operating 717-400 then he would see some aeration, and probably some increased ATF temperatures just like he saw with his differential test. The increased drag might even result in lower kilometers per gallon on the road, but so far I haven't noticed any (still in the high 30's/low 40's in 5th gear on the highway). For a transmission this old where many of the internal parts are NLA, a rebuild is an iffy proposition. I slight overfill on the museum car might not be appropriate but for this beast it's perfect fix. Thanks for posting (I enjoyed the videos).
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#9
10-10-2018, 03:36 AM
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Just thought I'd add the problem is usually the reverse idler gear shims in these gearboxes, as was touched on at the beginning of this thread.
A total stripdown is the official cure - forget it for a rattle at idle! See the last post in this tread: http://www.peachparts.com/shopforum/diesel-discussion/360329-getrag-5-speed-85-w123-300dt-2.html Mine is now silky smooth and silent at all speeds and I'll be leaving it just as it is! Thanks again Paul.
__________________
Cars owned: W108 diesel, hot rod Frogeye Sprite, unrestored pre war Hillman Minx.
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#10
10-10-2018, 07:09 AM
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Quote:
I consider things like gear rattle / whine , the slight smell of oil / fuel , solid lifter noise part of a older cars character, something sorely missed in modern cars. Quote:
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#11
11-09-2018, 06:28 PM
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Another update.
Banks All New Rear Differential Cover – Perfecting the Design https://www.youtube.com/watch?v=5_Jamg2gpgk
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#12
11-09-2018, 09:33 PM
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Quote:
__________________
1981 240D 4sp manual. Ivory White.
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#13
11-11-2018, 09:57 AM
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Shern you are welcome. You would also like the drag racer Warren Johnson, he came at the problem from an engineering perspective. Raised on a farm, he had the 60's NASA " We are going to the moon before the decade is out " work ethic all too lacking today.
I like his straightforward no BS style, and the ability to back it up with intelligence. https://www.youtube.com/watch?v=wcaWW9fkAXE SEASON 4, LEGENDS: THE SERIES - THE LEGEND OF WARREN JOHNSON and https://www.youtube.com/watch?v=hQlsohqB7To Warren Johnson talks about Bob Glidden I'm linking this with another thread in case I don't update this one. https://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/395119-differential-cover-testing-gale-banks.html
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#14
11-11-2018, 12:08 PM
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Quote:
I wonder what Banks would say if he saw the inside of the Mercedes rear diff covers used on most of their cars in the 70's-90's!
__________________
Von Fairport, NY 1973 Unimog 416 Doka 1980 Unimog 416 Doka 1981 Unimog 416 Doka 1984 Euro 280CE w/diesel conversion 1985 300TD Estate wagon (I really need to stop buying these things!) http://vonsmog.com
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