Intermittent auto trans noise in Drive when stopped

[Steve240]

Over the last 2 days I have noticed on a couple occasions my transmission has been making a groaning noise, only when in drive or reverse at a complete stop with my foot on the brake. The noise goes away as soon as I put it in park or neutral. There does not seem to be any add vibration or issue with the idle, very good idle steady at 600 in drive.

The noise also only seems to appear when the trans has warmed up. I checked my fluid when it was hot it was slightly below the hot marks but nothing crazy. The colour also looks good and it doesn't smell odd. Looking for advice, should I just get a flush and put new fluid in and see if that corrects it?

 

[bergeron37]

I had a similar issue with my 98 but it wasn't the trans, it was the exhaust. Only at a complete stop with my foot on the brake and in drive. I had a new exhaust put in a few months earlier and I think it was just vibrating a little, it has since gone away.

Are you positive it's the trans? I used to shift into neutral when going through the drive-thru at dunkies every morning because it was so loud I couldn't place my order

 

[Steve240]

interesting you say that I did just do some exhaust work, I put a new catalytic converter on this past weekend. Why do you think the noise goes away when shifted into neutral, less load on the motor? I also have never heard the noise while driving so I was fairly confident it wasn't exhaust related.

 

[bergeron37]

I don't have an exact answer for why, but when I was having the truck inspected I mentioned the noise to my mechanic. He had me get in and put it in drive with my foot on the brake, when it started making the noise, he just put his foot on the muffler and it stopped.

In my case, it only made the noise in cold weather, and oddly enough I have not heard it once this winter and Boston has been 10x colder this winter than last. I know it can be annoying but it sounds like the same issue and mine went away.

I would check to make sure that all the exhaust hangers are properly mounted especially if you had some recent work done. Also, I suggest reading this thread from yotatech, it's where I got all my answers for this problem:

Annoying rattle! driveshaft?? exhaust?? HELP! - YotaTech Forums

Hope this helps.

 

[Steve240]

Thanks the input, I will go smack my exhaust around with a mallet and see if I detect anything. I'm also going to pick up some atf and top it off. Hopefully your right and it's not transmission related but the noise is not really a rattle it sounds like a rotational groaning, hard to explain and very intermittent, it happen for 5 stop's in a row then goes away and doesn't return for the next 50 miles.