Driveline noise - 2000 Xtra Cab 2.7 Auto

Ok, so I'm new here so please allow me a little bit of newbie slack. I just bought my son a 2000 Tacoma Xtra cab 2WD Pre-Runner 2.7L with auto trans. 157K miles. Very clean. But I have a noise that I need to get my head (and wrench and possibly wallet) around. I hear a noise that sounds like drive belt squeal (but is not) on deceleration after letting off the throttle at about 35mph. Sounds like it's about mid-truck, just behind the driver's seat. Sometimes lasts several seconds as I'm coasting and sometimes is momentary. I can make it happen by applying throttle from idle speed to about 3500 rpm and then quickly letting off the pedal. What's weird is that when it is happening, the road vibration affects the squeaking. Almost like a loose frame bolt or something.

I put the rear axle up on jack stands the other night and had my son sit in the driver's seat and try to replicate it, which we were able to do ever so slightly. Could not get it to emit the sounds for several seconds, just momentarily. Sounded to me like it was coming from the area between the slip yoke and the pinion shaft. All ujoints looked like they'd never been lubed in their lifetime so I took it to the dealer for a $25 oil change and zerk lube. Didn't make a difference. Noise is still there.

Anyone here ever experience the same? In searching Google I have come across a few very similar complaints/descriptions but no real follow up on a cure.

I don't think it's in the diff itself as that would likely be a constant noise and not so hit and miss. This noise sounds like something really dry, maybe the slip yoke itself? Does removing the shaft, separating the yoke and lubing the crap outta the splines work on these trucks. Might that process also rid the truck of the annoying axle thump/driveline wrap/ that seems so prevalent?

HELP!!!!!

 

Bump.

 

Try doing adding a "add a leaf" to the rear to prevent axle wrap.

Lube the absolute piss out of the zerk fittings. Keep lubing till clean grease starts squirting out. Dont do that to the ones connected to the drive shaft, because those will just fill up with lube and make the shaft unbalanced. Just hte zerk fittings on the u-joints themselves and the double cardan. I recommend lucas red-n-tacky mainly because red is easy to see when all you have gushing out is gray nastiness.

Try lubing hte splines if you like

I'd also look at replacing the carrier bearing. It might be causing some of the squeak and vibes if you feel any.

 

Check your gas tank guard. I don't know about on a first gen, but my second gen the guard bent back into the driveshaft.

 

When mine squealed similar to that it was the center support bearing (the zinc colored dodad that is between the two drive shaft sections. A new one and the sound was bye bye. If you end up changing that, might as well put some new u-joints on the trans side and the diff side. LEAVE the cardan joint alone

 

I removed the driveshaft today for the sole purpose of greasing up the slip yoke. Found the rear u-joint clunky so I'll have a driveline shop replace it. The cardan is ok all around so I will leave that as is.

As for the center support bearing, how easy is that to replace? I assume I have to find a way to get that nut off the front driveshaft in order to get the bearing off, right? I don't have air here at the house.

 

Durrr... yeah that's the carrier bearing now that I think about it

 

very easy to replace. That nut is staked so just use a punch and get the stake out. Then put the flange in a vice if you have one and loosen it. If you don't have a vice you can try to loosen it while still attached to the truck which will hold it in place. Then I took a hammer and tapped out the driveshaft from the flange. Once that is off the center support bearing will come off, it may need a little persuasion. Goes back in the reverse order, just make sure you re-stake the nut so it won't loosen up on you.