Manual Transmission issue...
 

I have been getting some noise from the transmission recently... a buzzing that sounds like a loose skid plate. It happens in every gear, at around 2000 Rpm. As it sounds like something loose and vibrating, I checked all of the plates, the heat shield on the exhaust manifold, etc., and everything is tight. There are a few reasons I'm thinking it is transmission related.

First of all, it does not occur until the engine has reached it's nominal operating temp. Second, and this is the main reason, the original tranny started doing the same thing at the end of 2016, and ultimately ended with a synchromesh failure in 5th gear. The transmission was replaced with a new unit (Aisin AR-5) in January of 2017. Unfortunately, and also quite frustratingly, the warranty from GM was for 12 months or 12,000 miles. It has been 14 months, and 15,000 miles since the replacement so it would seem I am **** out of luck at least with regard to getting this done under warranty.

So... my questions for you are:

A) Has anyone else experienced anything like this?

B) As this is exhibiting exactly the same symptoms as last time, do you think something else could be to blame, e.g., transfer case, etc... something the transmission is attached to?

Am open to any suggestions at this point... I realize this is going to be an expensive fix, but I'd rather not have to go thru this again a year or so from now. Thank's in advance.

I guess that's a "No"... :rolleyes:

Has the vehicle been checked over by a professional to confirm your diagnosis? If it is the transmission what does the fluid look like? A fluid change might solve your problem. Is something else causing the failure, like a bad transfer case bearing?

I would check the linkage from the shifter all the way to the trans, drain and replace the fluid.

Throw-out bearing or maybe the fork?

Thanks for responding WR3NCHE4D. I had it into my local GMC dealership multiple times to diagnose this issue the last time it happened. Fluid was always clear and they could find nothing else wrong, and based on the cost of replacing the unit with a new, warrantied AR5 I decided to let it go to see what would happen, which ultimately, months later, was the failure of the 5th gear synchro. At that time the new AR5 was installed, and was operating perfectly until the last couple of weeks when the same 2K Rpm noise/vibration started again.

I have not had it back in for diagnosis as I thought I would reach out to you guys first to see if anyone had either run into a problem like this previously, or had any ideas that I had not thought of. My gut tells me that this is a systemic problem, e.g., not necessarily the transmission itself, but rather something it is attached to, such as the transfer case.

Thanks for responding TAINTER... I did not think of the linkage(s). You are talking about P/N's 224 and 297 correct? I thought of the throw out bearing, but dismissed it as the 2K Rpm noise/vibration was gone completely after the transmission was replaced. Am really frustrated by this as from what I am able to discern these AR5's seem to be remarkably good transmissions, and my experiences over the last two years appear to be the exception and not the rule.


https://cimg8.ibsrv.net/gimg/www.hum...e76ba01b02.jpg

Thanks for the suggestions and will have them check both of those when I bring it in to have the transmission torn down, which is now looking like an unescapable eventuality.

I would also check on the Pontiac Solstice forums. They use the same manual transmission as the H3 I5 manuals.

Guys... just want to bounce an idea off of you. Do you think there would be any value in trying a higher viscosity or synthetic transmission fluid. The weather is warming up here in the northeast and I noticed over the last couple of days that the noise is not based on whether or not the fluids are up to their normal operating temperature, but rather how long the transmission has been operated, which could be a case of the transmission oil becoming less viscous as the fluid temperature rises.

As said earlier. Drain and replace the fluid. All gear oil breaks down eventually with either time or use. Hope it's just the fluid.