Tranny noise

[JQ911]

I have read a lot about the common noises of the 915. I noticed mine sounds like a chain drag or coffee bean grinding when you;

1. Ease up the gas pedal at any gear except 1st
2. Gear is under load
3. Gets louder after long drive. Next morning, noise is not that loud anymore. This one started a month ago. Before, noise is the same whether I drive 5 or 200 miles.

Gears shifts perfectly except for that noise. I plan to drive to Bakersfield which is about 110 miles this weekend but kinda worried it gets worst. The sound has been there since I bought the car 3 years ago except that it developed a louder noise after a long drive. I'm using Kendall.

Is it time for a rebuild? Any recommendations where I can bring it within the Walnut or West Covina area?

[DRACO A5OG]

First, do you have a 915 with LSD? If so did you use the Kendall with LSD additive?

How did the magnet look when you changed the gear lube? Fuzzy Metalic residue?

[Matt Monson]

Differential doesn't rotate internally in a straight line. I suspect a bearing or the ring and pinion is about to self destruct. Might already be substantial damage.

[JQ911]

Originally Posted by DRACO A5OG

First, do you have a 915 with LSD? If so did you use the Kendall with LSD additive?

How did the magnet look when you changed the gear lube? Fuzzy Metalic residue?

Changed gear lube a year ago and will change it soon. Last time I checked during last change, gear lube smelled garlicy and kinda what you described. Yes, 915 had LSD and kendall w/LSD

[JQ911]

Originally Posted by Matt Monson

Differential doesn't rotate internally in a straight line. I suspect a bearing or the ring and pinion is about to self destruct. Might already be substantial damage.

I hope I could bring it somewhere kinda local to me

[DRACO A5OG]

Where in socal are you? If in LA or OC, pm me I can put some fresh ears on her :-)

[ganun]

yes drain the oil and look at the magnet and oil but also make sure its not an axle or wheel bearing. Doesnt do it in first perhaps because the wheels are not turning fast enough for the bearing to make noise.....>>>leads also to a diff carrier brg.

[JQ911]

Originally Posted by DRACO A5OG

Where in socal are you? If in LA or OC, pm me I can put some fresh ears on her :-)

I am in Walnut. I went to the Coffee and Cars last Saturday and on my way home, caught heavy traffic on PCH on ramp to 110 N and it was snail pace until we got stuck for 30 minutes (not moving). Apparently, there was a volvo burning that was apparently hit from behind by an audi. We were able to pass when fire was neutralized. With me caught in traffic, my temps was going up between 2nd to the last bar and bar below it, I decided to turn off engine and got out of the car as most of them were already outside watching the burning car. Then after a 40 mile drive I heard the sound of the tranny a bit louder than before. Next day, sound went back to usual level.

[DRACO A5OG]

Well PM me if you want to meet up. Walnut is not far at all

[kodioneill]

Are your transmission and engine mounts in good shape? If they're old and brittle you will get a lot of noise transfer into the cabin. I worked on a race car with solid mounts and you would not believe how loud the transmission noise is while driving.

[JQ911]

Yes, tranny and engine mounts were replaced a year ago. Drove it today and sounds fine except when I drive it for more than an hour or long distance the sound tends to increase but when it cools down, the noise is still there but not as evident when driven for a longer period. Happens on decel between 2500 to 3500 rpm

[DRACO A5OG]

Not for nuttin, but have you checked the fluid level?

[JQ911]

That is actually what I was thinking. I changed tranny fluids last 2013 and xmas 2014 but it was so cold during that time so I am not sure if I accurately put enough but as I recall, it was dripping when I was pumping so I thought i had enough before I closed it. I will try to open the filler plug and put my finger to check if i can feel oil.

[Bob Kontak]

Originally Posted by JQ911

Yes, tranny and engine mounts were replaced a year ago. Drove it today and sounds fine except when I drive it for more than an hour or long distance the sound tends to increase but when it cools down, the noise is still there but not as evident when driven for a longer period. Happens on decel between 2500 to 3500 rpm

Here is the deal from my definitely arm-chair knowledge. I have way more arm chair vs. actual transmission experience so you get what you are paying for.

The 915's and I believe G-50's, and for sure the G50-50's on the 89 turbo (cause I heard it on a 20k mile garage queen) have the chain dragging noise. But it is limited to taking off well below the power band. Meaning, if you are giving the throttle three beans rather than 25 beans, it will chatter/shudder a bit. Once RPM's climb a wee bit, it shuts up. That is the norm. Take off in a serious manner and you don't hear a peep.

Since you are experiencing this regularly in other than the norm, you must (may) have a problem.

Cold fluid quiets it down.

I would take up the DRACO offer in a heartbeat. Let him drive/listen. He can observe motor mounts and compare to his car's operation among other things.

I would also listen to Matt Monson with a really big ear. He is very good and works on P car transmissions for a living. He has advised me (taken the time - which is expensive) on tech stuff that I never received a clear answer on from other pros. If he says something about the differential and straight line rotation, listen.

I would get local confirmation of if you have an issue. Also, engage someone local like DRACO to help you pull your engine/trans if in need of repair. PP helpers can be a God-send. Way more of them in CA than Ohio. Pay him some real money for his time. Not $1,500, but several hundred. Pizza/beer mandatory. Then ship it to a pro for repair.

Matt, Mayo, John Walker or recommended folks in your area.

[JQ911]

Hi Bob, I will definitely look into this after my out of state trip. I will keep you guys posted and might pm Draco once I am back on the 15th. Thanks