So we have had this suburban for about a year. A few days ago (with no other obvious warnings) a ticking/tapping noise started. Details are as follows:

-Happens only in acceleration both reverse and drive
-In reverse is very slight/faint
-In drive while accelerating lightly is the loudest
-while accelerating heavy still there but faint
-does not happen during idle not matter the gear
-does happen in 4wd hi and low
-coming from underneath (torque converter possibly trans)
-shifts gears fine
-trans fluid is nice and red and smells fine
-when you check trans fluid while running air bubbles present on dip stick
-noise is random - no rhyme or reason to the times it happens but is getting more frequent/often over the days

things that could be related
-about the same time this started when standing in idle in drive only, truck idles real rough but does not do this in other gears
-pulled plugs today they are extremely corroted (sp?) however this is not the problem (in my opinion at least)

Any ideas on what this could be: read several online sites with the same possibilities we are thinking, planatery gears, joints, torque converter. Just would like to minimize the possibilities if possible.

Thanks in advance for any help!!

 

Welcome to the forum.

Might be a loose torque convertor.

 

Hmmm really, loose not bad? thats an interesting idea

Thanks for the welcome! Sorry to just go into issues rather than all the intro stuff first but the wife is 4 weeks away from her due date and I do not want to be on the way to the hospital with her in labor and something finally give out completely.

 

I had similar sounds in my 94. I would check the U-joints in the drive shaft. That was my issue. If it still has the stock U-joints installed you'll have to take it to a shop to be replaced; as they need to be heated to be removed. I tried for a day to press mine out before a figured this out.

 

Wouldnt the u joint do this only when moving? I only ask because I can replicate the sound in my driveway. The wife puts it in drive and holds the brake while revving the motor and the sound is there.

 

You are right mine only made the noise while moving.

 

first thing that comes to mind is an exhaust leak.....power brake in neutral?? and does the ticking respond with RPM?