2nd Gen Taco Autotranny whirring noise only when moving.

Hi All

My new to me 2006 SR5 with A340E transmission seems to have a slight whirring/grrring noise when it is in motion. Definitely corresponds to speed from very slow and increasing in frequency until moving fast enough that other noises drown it out. I put it up on a lift with the rear wheels free and listened with a stethoscope to the rear trans, drive shaft support bearing, and pinion bearing. Could hear nothing. While riding in the truck it sounds like it is forward near the trans tail shaft or perhaps the drive shaft support which seems smooth and quiet when I pulled it to check all the drive shaft parts. Sort of reminds me of some older automagics that had their parking pawl not fully disengaging and rubbing on the cogs. Can't find any info on whether there is an adjustment or solenoid related to operation of the parking pawl. Pawl holds the truck just fine in Park. Anybody else had similar noises.

Thanks
Geezer

 

With it on the lift was the wheels hanging free? That may be why you didn't hear anything. I would suspect a heat shield rubbing the drive shaft from the description.

Could also be a universal joint or center bearing. The only good way to check is to drop the shaft out of the truck.

 

I had the parking brake on slightly to simulate a load on the drive line when the wheels were in the air. Also pulled the drive shaft to check the UJoints and support bearing and they all were smooth moving with no play or noise. Could detect no slop in the driveshaft nose where it fits into the trans tail bushing. All fresh ATF and diff oil.

 

if its tranny, could be front pump. Make sure to eliminate engine pulleys/idlers, noise travels.

 

But would a front pump only make the noise when the vehicle is moving? I thought the pump operates whenever the engine is running or it is in gear. Just installed a 86K JDM motor and replaced all pulleys, tensioners, belt, H2o pump. Engine is so quiet that the only noise is the injectors faint clicking and some air noise from the fan. I had my GF drive it around a parking lot with me in the bed listening over the fenders as she swerved side to side etc, and could hear nothing except the tires rolling. I can only hear it in the cab up to maybe 10mph when road noise drowns it out.

 

get ur GF in the bed with you and don't worry about the noise . . .

 

Well, yeah, but, we want to make sure we can get home without calling AAA.