Marvel Mystery Oil & 5th gear whine

[lululalalu]

An independent shop replaced the manual tranny in my 88 SE5 with a rebuilt 10 years ago.

1 through 4 were always quiet. 5th was loud after the swap (quiet before).

I’m finally sick of the noise (it’s still the same, not louder).

I would like to avoid an input bearing job or replacing 5th due to missing teeth (two possible causes of the noise after a forum search).

Has anyone drained the tranny, filled it with Marvel Mystery Oil, drove around just a bit, and then replaced the gear oil?

Does MMO have a chance at quieting the problem (or is this a stupid idea)?

 

[cometobanks]

It wont fix missing teeth....

What is your thinking that it would help?

 

[lululalalu]

re. missing teeth - agreed, it won’t do a thing.

input bearing or misc. - I guess I’m hoping it will penetrate and clean ‘something’ related to 5th allowing fresh 80/90w gear oil to coat and help reduce the noise.

 

[cometobanks]

that would be very mysterious if it could.... WHat the hell, try it, but I wouldnt get hopes to high. Of course you might just piss 5th off and cause it to leap right out your tail pipe to...