ATF choices for making high speed pinions quieter

[ikeepmychevytoo]

hello there...

This is an older GM's THM 125 which gradually developed a whine in the first gear. A former GM mechaic who once assembled new clutch packs says noise is the planeter pinion gears with a higher speed and there's no need to be concerned for mechanical reliability for quite a while.

Well, I can guess the degradation of hypoid gears, but as the fluid change period is nearing may be I can get it quieter this time. I've been using Dexron III since it was avaible. On another thread I've asked about the differences of the Dexron fluids and MolaKule kindly re-posted this useful thread.

So, would a Dexron-II with higher zinc would help in quieting the high speed pinions, or should I go with the Dexron-III E (or the newest spec I can find), or else do I need to look for highest viscosity cSt@100°C ? With the longer OCI of the ATs I'm having a hard time for deciding. Opinions please...

 

[MolaKule]

quote:

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Well, I can guess the degradation of hypoid gears,

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What?


Fluids are not going to cure the tranny problem.

I find some noise is produced by the torque converter as well.

Some of the noise may be reduced by using the highest viscosity ATF you can find, but it will not cure it.

We make racing ATF in a higher viscosity so

contact us at

[email protected] .

 

[ikeepmychevytoo]

of course, I don't expect any mechanical reversability. Let's put it like this, I've seen cars with loud first speeds from the day one. I guess, this is somewhat typical of ATs. Mine is one shade louder and I thought some oils may be quieter just as it is for the engine oils. May be some part of the sound is just due to the nearing OCI and a sheared down oil.

I've noticed Dexron II oils also spec. MB 236.6 while Dexron III additionally specs MB 236.1 and 236.5. I'm not sure what this should give though.

ps. I wonder and would try many oils mentioned here, what bugs me is the shipment costs that virtually quadrouples every quart.

 

[unDummy]

Try the Pennzoil/QS high mileage ATF.