Transmission break-in/Howl

[sgtnoah66]

I did some searching on this as I’m pretty sure I’m not the first person to encounter it, but didn’t have much luck.
Just put in a freshly rebuilt transmission from a reputable vendor. There is a distinct howling noise in all gears that disappears when I let off the gas. Much louder than the old one that came out. Wondering if this could be a break in issue that Will disappear with time, or if I have issues? Any thoughts would be much appreciated!

[67rustavenger]

My rebuilt trans is quiet. And I currently have the back seat out of the car. You can hear everything with it like that.

I'm no trans expurt (<Tucker speek) but IMO they should be quiet when new. Before the rebuild. At 65mph the racket the trans was making was deafening.
maybe the builder messed up the R&P setup. IDK.
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[mukluk]

Excessive R&P backlash would be my first thought.
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1960 Ragtop w/Semaphores "Inga"

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Is this a stock rebuild replacement in stock mounts? Or is this a former stock trans/stock mounts, that have been changed to a performance trans/performance mounts?

Like others have mentioned, ring & pinion backlash/depth can be a cause for noise in all gears if it’s not a bearing issue.

Contact the builder to see what they have to say.

[sgtnoah66]

This is a stock rebuild on a swing axle transmission with stock type mounts

[Chuck67]

Stupid question-

Is there oil in the tranny?

[Cusser]

The rebuilt transmission I purchased in 2018 was quiet from the beginning.

Yes, I had to add gear oil, and expected to; but it had a wired-on tab stating to add gear oil anyway.

I would contact the supplier of the transmission; for the record, my rebuilt transmission was from MoFoCo.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[malley56]

I also purchased a newly rebuilt stock tranny from a reputable vendor. It’s using stock mounts. It has a light howling in 4th gear under load. Let off the gas and it goes away. I wouldn’t call it “that” loud but the old tranny was quieter. Contacted the vendor and they indicated it had been tested. Its not that bad and it’s not worth pulling it back out shipping waiting etc.. I’ve tried a couple of different oils and the Swepco is the quietest so far. I have about 500 miles on it and it’s gotten a little better. Good luck and let us know how it turns out.

[sgtnoah66]

Thanks for all the feedback/info. I will call the vendor tomorrow and see what he has to say. Running GL4 80-90 and filled it and then topped it off the next morning To account for it seeping into tight areas. Since it does it in all gears and only under acceleration, I’m quite certain that it’s the ring and pinion shimming/tooth contact.

It will be interesting to hear what the vendor says.

[jpaull]

That howl is classic for the pinion depth being off. I hope the vender doesnt tell u its normal or to live with it.
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[sgtnoah66]

I talked to the vendor today and he seemed really good about it. Told me to drive a few hundred miles and if the noise doesn’t go away, to check back in with him and he would send me a replacement transmission. Seems reasonable.

— Pete