Truck thumping noise diagnosis

Hoping to get suggestions about the source of a rhythmic thumping noise that I'm getting from my 2003 Tundra. I can hear and think I can feel the thumping from the undercarriage somewhere. It's not very loud and it gets faster as the truck speed increases. It sounds to me like a pump knocking. Crawling underneath, the U-joints seem tight but there's a drive shaft center support bearing where the shaft has some play, maybe 1/4-3/8 of an inch. I don't know if that's normal. It's in the center of the picture.

The transmission seems to function fine and the exhaust system is tight. Perhaps it's another bearing, mount or bushing. What do you think? I've scheduled an appointment with the Toyota dealer service for next week. If it is the center support bearing, it would seem to be a simple fix. How serious is it? Can I tow a trailer to Grand Junction and back before fixing? What am I looking at for cost? Would a non-Toyota brand part work as well and would an independent shop be cheaper?



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I don't have your answer, but can you be more specific about when you hear the noise? It sounds like all the time. Is it correlated with RPM, or wheel speed? Does acceleration/deceleration, or shifting affect intensity?

Center support bearing is collapsed, its plain as day in your pic. There should be no appreciable movement on a center bearing.

Have you tried jacking up the rear and putting it on jack stands? Chock the front wheels and have someone rev the drive train some. See if you can see the source of the vibration. If the center support bearing wobbles it is probably the rubber has lost its firmness. Watch the wheels when they spin, a wobble could show pothole damage. Or a bad axle bearing. Make sure the drive shaft has not lost any welded on balance weights. Make sure no differential seals are leaking oil. Hope this helps. The bearing is removed and replaced by only two bolts. Should take less than an hour to R&R.

https://www.youtube.com/watch?time_c...ature=emb_logo

Did you check tires for defects?
Check tires for balance? Maybe you lost a wheel weight?

Yeah, that carrier bearing looks off center to me. Probably time for a new one.

Thanks everyone for your suggestions. I'll let you know what we find.

Get it figured out?

They tell me it's the limited slip rear differential. Not cheap. I've hauled a lot of heavy loads with it. The truck has 220K miles but I'm not ready to buy a new one. When I do my plan is to make this one into a snowplow rig and sell the '85 SR5.

That sounds suspicious. Have you had a second opinion?

^^^This.

I would do the carrier/center bearing myself, it needs done regardless, especially if going to be plow truck.

If issue continues then get second opinion.

The diff shouldn't thump. If it's getting old, it would need a fluid change and maybe the clutches are wearing. Even if the clutches are worn, it'll just act like an open diff.

I'm inclined to trust the Toyota mechanic who has 26 years of experience. At any rate I've committed so we'll see how it works when it's done.

Seems to me the carrier bearing was replaced before but I don't have the records with me to search.

My first thought because I'm a prankster, was zip ties. Sorry it wasn't that though.

Talk to Noah, at Peak to Peak Imports, in Ned. He’s good.

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Originally Posted by Ah Pook

Talk to Noah, at Peak to Peak Imports, in Ned. He’s good.

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Thanks for the tip, I'll keep it in mind, particularly when my '85 toy plow truck needs help. I try not to take it to the flatlands and mostly only go to Ned for gas.

Partly because the truck wears studded tires year round.

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Originally Posted by Irving

The diff shouldn't thump. If it's getting old, it would need a fluid change and maybe the clutches are wearing. Even if the clutches are worn, it'll just act like an open diff.

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Thanks for your comments. I've never had a differential problem in a vehicle. U-joints, carrier bearings, clutches but never killed a transmission or differential. I've raced cars, rebuilt engines and done a wide variety of mechanical work from motorcycles to heavy equipment but now I'm at the station in life that I can let specialists do the high tech or heavy lifting work.

Apparently the Toyota mechanic readily heard knocking in the differential with a stethoscope.

A few other points that were suggested; the tires are new, everything good there. All the fluids were changed in early March. Actually, I suspected the differential and that it might have been drained but not refilled, but no. At the cabin I don't have a garage or a safe lift, only ramps. So, to the shop it went.

For the past several months i've been hauling heavy loads of apple wood from Palisade. It's now more expensive smoking wood and firewood. [Roll1]

Let us know when you do decide to let that '85 go please.

Fetzer valve.. or maybe the ball bearings..

https://www.youtube.com/watch?v=ok8ba-DsRhE

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Originally Posted by Irving

Let us know when you do decide to let that '85 go please.

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Rusty like all early toy trucks but it's a gem. I paid $750 for it, added extra leaf springs and a Meyers snowplow. It was the last year of the solid front axle which is ideal for a strong plow rig, and the first year of the electronic fuel ignition. 278K miles on the original engine and it starts right up. Even the cruise control, electric windows and air conditioner still work (alhough they're of marginal value with the little 4 cylinder engine). The little Toyotas make for super snow plow rigs, fast, efficient and reliable.