Getrag rattle and how to alleviate it
Hearing the Getrag rattle for the first time can be unsettling. This rattle is a common sound produced by Getrag transmissions, especially the 5-speed models found in E30s, BMWs, and GMs, when the car is in neutral and the clutch is not engaged.
The rattle disappears when the clutch pedal is pressed or the car is in gear. People often describe it as sounding like a bag of marbles, gear chatter, or similar metal rattling. It’s not a fault within the transmission; rather, it is the unengaged gears vibrating against each other.
If you’ve ever heard an 18-wheeler idle in neutral, you’ve likely heard a similar loud metal rattle. This noise is due to the play in the gears when not engaged, and it’s louder in an 18-wheeler because the gears are larger.
As the transmission accumulates miles, the rattle may become louder due to the gears and bearing clearances increasing slightly. This is not indicative of transmission failure but can be annoying and sometimes embarrassing.
The noise can be significantly affected by the type of transmission oil used. Thicker oil makes it harder for the gears and bearings to move around. A good solution is to mix one part 75w80 (or similar) with one part heavy weight oil like 75w-140 or 85w-140.
Using overall thicker oil will make shifting more difficult in cold winter weather until the transmission warms up, so keep that in mind.
It’s crucial to use GL-4 oil. While many oils in North America are labeled as GL-5 “compatible” for GL-4 applications, the composition of these grades is fundamentally different and not truly backward compatible. Below is a technical explanation of why GL-5 is not a true substitute for GL-4.
Download (PDF, Unknown)
http://www.widman.biz/uploads/Transaxle_oil.pdf
I was able to find this oil from Europe which is exclusively rated gl-4 and for manual transmissions:
http://www.eurol.com/en/37-products/…w-140-gl4.html
Which I was able to order from amazon.de from a seller who ships internationally:
http://www.amazon.de/gp/product/B019…021_TE_3p_dp_1
I got a 5L instead of a 4L, nice 1L bonus!
This entry was posted on December 9, 2016 at 4:05 pm and is filed under Do it Yourself. You can follow any responses to this entry through the RSS 2.0 feed.
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Hi,
I had the same issue with the Getrag gearbox.
Initially some of them were filled with ATF oil. Some can tell by the sticker on the right side of the transmission, near the bell housing.
My car’s gearbox was really noisy. I felt ashamed even because of it.
I decided to change all the bearings inside. To be sure about the quality (you can buy very cheap or very expensive bearings same type) I ordered all from the BMW. Some are very specific. Repair took some time as mechanic was unable to open the transmission so after few weeks I took it and did it by myself. I was sure I will help as some of the bearings had some wear marks on the rolling parts. I was shocked in the end because it did not really helped.
It was frustrating.
That time my friend suggested to fill the transmission with the mineral oil according to BWM specification. I did and… it worked! It was really quiet from now.
The only disadvantage was the problem with gear change during the winter for the first meters of driving.
So I can agree with the author. Do not spend money on the gearbox as long as it is not loosing gears. Just change the oil to higher grade one.
Cheers