LammMorada

Has anyone out there experienced a moaning sound that comes from the automatic transmission during upshifts?

My 928 is a 1980 model with the 3-speed automatic.

The tranny shifts fine, and the fluid was recently changed (Dexron III). Fluid level is toward the upper limit on the sight gauge when checked warm, with the engine running and the transmission in neutral.

The sound isn't terribly loud, but it's definitely audible. It's rather like a cow mooing. And the moo (or moan) doesn't take place until the transmission warms up. Nor do I hear it during hard acceleration. It's audible only in normal driving with a warm transmission.

Any thoughts?

Thanks.

-Michael Lamm, Stockton, California

AO

First off, welcome. Thank you for taking the time to post the MY of your car; that helps tremendously.

I'm sorry I don't have an answer for you (only had 5-speeds) so the best I can do is offer you a friendly bump to the top. I'm sure some of the auto gurus will chime in shortly.

ZEUS+

Usually a noise from an auto is from the pump.

jpitman2

There is a note in the WSM re a change of one of the cooling hoses at the box to remove this noise. IIRC its a slightly longer hose part so that it can be run in a loop before joining the forward steel line. Seems like the noise is a resonance in the hose if its short. If you ever get a power steering inlet hose to pump collapse or get restricted, you will get some awful noises from it.
jp 83 EuroS AT 51k, between radiators.

Charley B

Welcome Michael. As a resident of Stockton, you are eligible for membership in the Stockton Sharks Society. Being geographically challenged by 20 miles, I can only qualify as an associate member. Your perks will be much more attractive than mine. For instance you will be allowed to help Brian (Iceman17) prepare his S4 prior to all concourse events.

Never heard of the moan you speak of, but I'm shocked to read Pitman says there is a note in the WSM regarding the change needed to eliminate it.

If you don't have access to the WSM, send me a PM or e-mail with your e-mail address and I will send you a link.

Mrmerlin

Welcome to the board, Mike, if this doesnt offer you any info i would suggest atleast checking/changing the trans axle gear oil.
Though the moan may be from the ATF lines a low oil or old oil might cause noise

IcemanG17

Michael
I see you found rennlist...congrats on that...you have found the holy grail of 928 ownership!!

As for helping me prep my 928 for concours....well I don't see much of that happening anytime soon!! Maybe an autocross or DE...but no more concours for me!

Your transmission sound does sound like a torque convertor bearing going bad...or possibly a torque tube bearing....but the "only when warm" does sound a bit odd......I'd have to listen to it in person to be sure......send me a PM I'm off tomorrow!!! The only thing on my schedule is fix my heater valve AGAIN!!!!!

jpitman2

Why are you shocked , CharlieB? IIRC the WSM has several notes here and there about changes to things along the way to improve operation or part life, like the timing belt tooth form change.
jp 83 Euro S AT 51k

Charley B

Shocked is probably the wrong word. Surprised that the problem was so prevelant that they came up with a diagnosis, a solution and added a note to the WSM. I love these cars.

Jim bailey - 928 International

Also in the auto trans section there is reference to hitting the trans with a wooden mallet not to cure the moan but to free up an internal part which can get stuck... I love that one....when all else fails hit it with a hammer !!!

Mongo

Are you serious?! I'm going to look that up as soon as I get home! That's hilarious! A little German Engineering Humor I'll bet!

Charley B

Talk about your oxymorons.