Tranny noise when decelerating - fixed.
 

For about 1000 miles I've noted that when I am decelerating the trans has started to get noisy when hot. Like a rattling/whining type sound of distressed machinery. It's most obvious in 2nd gear. Toe the throttle slightly and it instantly quits.

I changed out the trans oil which was Mobil 1 75-90 synthetic gear oil which I put in when I got the car about 1000 miles ago. Yesterday, I put in a normal off the shelf 75-80 gear oil. Instantly quieted down. Turns out I'm a dummy.

Investigating why this might be so, I read on the Mobil site that their gear oil is NOT GL-4 recommended. The 944 manual clearly calls for GL-4. The oil I installed is GL-4. In addition, its supposed to have 80w. So I suspect when warm, the 90w was too thin and allowed various bits to rattle around noisily though without engine torque it was largely just annoying to listen to.

Lesson learned. I will update if it stays quiet. Even my wife noticed the difference!

Ftw if it’s a street car use this and it’ll feel like you’re driving a different car.

http://forums.pelicanparts.com/uploa...1559664905.jpg

Thanks for this information. I have the same issue and wondered if a regular, non-synthetic gear oil would be more appropriate given the era of the transaxle. A friend with a 914 noticed that when he put in synthetic oil in his TA it would shift horribly but with regular dyno oil it shifts perfectly.

Can you post up the brand you used and where you got it? I had my TA rebuilt several years ago and it still makes the same noises.

Hmmm. Was is the “coffee grinder” sound you had ? I have the same issue but all research here led me to believe it’s the pinion bearing. I’ve done a clutch but I’m not rebuilding any trannie. I bought another one but have yet to install so I may try the fluid change first. Really not sure what’s in mine and can’t recall if I have flushed it since I’ve owned it or not.



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Kinda hard to hear, but at least for me this is the noise I'm hearing.

https://www.youtube.com/watch?v=ZtokNfiKaHg

I have MT-90 in my TA now and no difference. Same issue with Valvoline 75w90 and Swepco.

That sounds about like I recall mine doing. It’s been on the lift for months with locked up brakes and taking a backseat to other projects.
Mine was most obvious at low speeds in parking lots or approaching stop signs etc.
noise stops if you shift into Neutral right ?


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