What the CLUNK is going on with my 2000 4x4 SR5?

[Jetcycles]

I've read just about every thread on the dreaded T4R clunk, yet I still can't track down the clunk/pop in my 2000 SR5 4x4 auto T4R. The noise started a few hundred miles ago as a slight ticking sound and has progressively gotten worse, to the point that I can now feel the knock/pop/clunk in the rig that increases/decreases with speed and I'm afraid to drive it much as I don't want to prevent further damage. The noise is present in forward/reverse, 2wd and 4wd, and does not increase/decrease in intensity while turning. The transmission shifts smoothly through all gears, and I can engage 4H and 4L with ease. Some background; Roughly 190,000 miles, Sonoran Steel 1.2 and new LBJ's installed at 185,000. Drive shaft zerks greased last week (haven't driven more than 1/4 mile due to wanting to prevent further damage from what feels like hard parts binding when I drive, do I need to drive it further?). Both inner CV boots were shot and the passenger side had a little bit of play so new CV axles went in both sides this weekend, diff drained and refilled with Lucas 75W90 synthetic, very little metal on magnetic drain plug, no change in sound. So far I have checked:
-lug nuts are tight, center caps are tight, and there are no rocks in the tires
-no noise while stopped so I don't think it's the flex plate
-Rear diff fluid drained and replaced with Lucas 75w90 synthetic (very little metal on mag drain plug and the fluid was still fairly translucent)
-Rear end placed on jack stands, wheels pulled (and brake hardware inspected) and I don't hear anything other than a bit of brake drag when I turn either wheel. No discernible up/down or left/right play on either side.
Front end placed on jack stands, wheels pulled (and brake hardware inspected) and I don't hear anything out of the ordinary when I turn either wheel. Almost no up/down or left/right play on either side.
-The differential mount bushings look shot, could this cause my issue, even on flat smooth roadway?

I still need to check:
-U joints with the drive shafts removed
-sway bar end links
-UBJ's
-Differential drop hardware
-Transmission and engine mounts
-How would I diagnose bad front or rear diff bearings?
-Steering is pretty tight for a vehicle this old, but I'll check the rack and end links

Would I hear a bad wheel bearing on jack stands at hand turned speeds, or do I need the wheel bearings to be under a load? Can I safely check these on jack stands? Can you add anything to my list of items for me to check off? Any insight and constructive criticism is greatly appreciated. Anyone on the Southeast side of Houston (La Porte) that knows these rigs better than me that I can reach out to? I'm not afraid to pay someone to make the necessary repairs if they are beyond my comfort zone...I just don't know what the heck is going on! Thanks in advance for even reading this, I want my rig back!

 

[Scramble]

I dont think it's your wheel bearings, they usually whine when going bad. I had a clunk a few years ago along with a drive shaft vibration. They both started at the same exact time when I got on the highway after a day of wheelin'. It ended up that my Double Cardan joint was going bad. It had no play while on the truck but had movement when removed.

 

[phattyduck]

Since it is there 2WD and 4WD, it is likely to be something with the rear drive components.

Take off the rear driveshaft and drive in 4WD (FWD with rear shaft removed) to see if the problem goes away. Also check those u-joints manually. Don't pull the driveshaft apart in the center unless you know how to re-align it when you put it back together.

-Charlie

 

[JGrauman]

Definitely sounds like bad ujoints. Grease them until you purge all the old grease out, if it decreases the clunk, still probably need to replace them.

 

[Jetcycles]

Thanks Scramble, I don't think it's wheel bearing either, but WTF do I know? I'll do some researching on pulling the driveshaft and inspecting the DC joint. In the meantime, if anyone knows of a good thread covering replacement parts I'd love to read it. Any idea if I can just lube it up and listen for a decrease in symptoms prior to pulling the drive shaft?

 

[phattyduck]

Thanks Scramble, I don't think it's wheel bearing either, but WTF do I know? I'll do some researching on pulling the driveshaft and inspecting the DC joint. In the meantime, if anyone knows of a good thread covering replacement parts I'd love to read it. Any idea if I can just lube it up and listen for a decrease in symptoms prior to pulling the drive shaft?

If you've got the grease gun, it takes <5 mins to grease the shaft. Go for that first. Then drop the shaft (assuming no major rust, about 10-15 mins) and manual check it and drive the truck in 4WD (errr... FWD) to see if the problem goes away. You can have your problem proven to be or not to be the rear driveshaft in half an hour.

-Charlie

 

[AntleredRuin]

+1 for bad u-joints. Even if you put new grease in, if they were already old and rusty and worn out, that won't matter.
I had a bad u-joint in my 2wd a few weeks ago, and it was absolutely disgusting trying to change it. The thing was so worn out and dry that it essentially collapsed in on itself when pressing it out. Of course, the 2wd is a sealed unit (no zerks) but still. It squeaked like crazy going in reverse and clunked whenever i would let off the gas at freeway speeds.

I'd say remove both driveshafts (honestly is not that much more work than greasing the zerks). See if they rotate nice and loose in your hands. No binding, etc.

Also, +1 for the punny thread title :bigok:

 

[Jetcycles]

You guys are quick! Thanks for the prompt replies. After I started researching this issue last week, I greased the rear drive shaft but had a zerk that didn't hold, so I'll crawl under there and replace that zerk and give them another shot of grease after I get the girls to bed this evening. I may not have the time to pull the rear shaft until Friday afternoon, but I'll get it out and go for a short spin to see if I hear the noise. It seems as if the double cardan joints are made mostly of unobtanium...and I doubt I have the time/patience/talent to rebuild that myself anyway. If I can get the rebuild parts, can any of you recommend a reputable shop in the Houston area to rebuild my drive shaft? If I wanted to pick up a used drive shaft, can any of you recommend a good local or online source? It looks like all 96-00 4x4 auto v6 drive shafts are the same, is this correct? Thanks again for your time and info.

 

[AntleredRuin]

Houston Area?
North Shepherd Drive has like 15 junk yards. I actually just grabbed a new (used) driveshaft after my u joint collapsed rather than fight with it more. Like $50 out the door.

To my knowledge, driveshafts match through the years. Just make sure 2wd, 4wd, engine/tranny combo

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[phattyduck]

If I wanted to pick up a used drive shaft, can any of you recommend a good local or online source? It looks like all 96-00 4x4 auto v6 drive shafts are the same, is this correct? Thanks again for your time and info.

Car-part.com is a good way to search junkyards for parts.

99-00 Limited driveshafts are not compatible with the base/SR5 V6 auto 4WD driveshafts. The '96-'98 Limited are compatible. The '99-'00 Limited driveshafts match the '01/'02 driveshafts (all have the multi-mode case).

-Charlie

 

[Jetcycles]

Rear drive shaft is out, yet the mystery clunk remains. What's next? Time to check motor mounts?

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[Scramble]

Rear drive shaft is out, yet the mystery clunk remains. What's next? Time to check motor mounts?

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I'd check the trans mount/bushing/isolator, not sure what it called but it's in between the trans & cross member. I've seen a few members here replace theirs because it was basically gone.

 

[Jetcycles]

Thanks Scramble. Does this look normal? Or is there a bushing missing? I do see a bit of a leak between the transmission and bell housing. If I insert a large screw driver under the bottom of that mount, I can lift the transmission with (relative) ease. I'll see if I can tighten that bolt.

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[Scramble]

I've never even looked at mine so I dont want to give you wrong info. I'm pretty sure [MENTION=116387]Unner[/MENTION] replaced his. Or you can check his build thread in case he doesn't see this for a day.

 

[Jetcycles]

I know that sound can be very subjective, but I feel as if my clunk was slightly less obvious without the rear drive shaft in place. In theory, at least to me, it seems as if that center bolt in the transmission mount could cause the sound that I hear if it is making contact with the rest of the mount due to worn bushings. I drove very slowly down the street and could hear a bit of brake drag and the occasional clunk as the road surface changed.

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[Unner]

Thanks for actually posting what you've checked, and what you've done rather than just "truck is clunking help".

I'm not quite sure that I understand your clunk. Is it a cyclical noise that happens whenever the vehicle is moving and increases with speed? If so you might have better results with a different search term than clunk. Or is it a clunk that happens when you hit a bump or something like that?

If it is a noise that occurs whenever the vehicle is moving, I'd look at parts that rotate. If it is a noise that only occurs when you hit a bump or something like that I'd look at stuff like transmission mounts, rubber parts that fail.

Thanks Scramble. Does this look normal? Or is there a bushing missing? I do see a bit of a leak between the transmission and bell housing. If I insert a large screw driver under the bottom of that mount, I can lift the transmission with (relative) ease. I'll see if I can tighten that bolt.

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Yes, that is what they look like. You can't do anything with the big bolt in the middle. Best thing to do is check the torque on the 4 bolts that go into the transmission from the mount (48 ftlbs). And check the 4 bolts that mount the mount to the crossmember (13 ftlbs). Tacomas have the same mounting bracket, and I remember reading about people having bolts missing from theirs causing clunks.

To see if the mount itself is bad put a floorjack under the transmission and jack it up just a real little bit, and then look at the rubber on the transmission mount. If it is cracked very badly then it should be replaced.

For the diff mount bushings they cannot be replaced, you have to buy the entire arm. You can replace the stopped that goes on the top side of the bushing though. That stopper and bushing tend to get covered in oil on the driver side during oil changes which degrades the rubber.

I've never even looked at mine so I dont want to give you wrong info. I'm pretty sure [MENTION=116387]Unner[/MENTION] replaced his. Or you can check his build thread in case he doesn't see this for a day.

I need to figure out how to get my email notifications working again. I just happened to see this by chance...

 

[Jetcycles]

Thanks for the reply. I try to be thorough and methodical as that seems to net better results. The sound is not cyclical in my opinion, but it does (seem to) increase in intensity with speed and rougher road conditions...but that could just be wishful thinking. By feel alone, it seems as if there is only about 1/3" of clearance between that mount and the center fail safe bolt, and contact between hard parts seems plausible given the condition of those bushings. I'll post a better picture when I get home from the hardware store, might as well replace drive shaft hardware while I'm bolting the drive shaft back up. Thanks for the tip on the cross member and mount hardware, I'll check those and report back.

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[Jetcycles]

I'm not sure if these photos show much, but here they are. I couldn't find fresh drive shaft hardware at my favorite stop (only lock washers), I'll look them up online and try again. Didn't get to check any of the cross member or transmission mount hardware, a pipeline issue has me headed in to work. You guys rule, thanks so much for sharing your knowledge. Ignore those fluids...some of you boys could use the corrosion protection!

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[Jetcycles]

Although I'm not 100% positive that the transmission mount is the cause of all of my woes, I went ahead and ordered an OEM replacement from Camelback Toyota. For less than $100 shipped, it can't hurt to replace this part. Toyota actually refers to this as the rear engine mount (or insulator on some sites), part number 12371-62120 appears to fit 96-02 4x4's with auto transmissions. If this photo from the web is accurate, my mount looks pretty worn.

An added note: 4x Innovations sells a mount that looks like it will work for you manual transmission guys (it's technically for a tacoma, so don't buy it on my verbiage alone!) but nothing for us w/ autos. With a 2-4 week lead time and requiring paint upon arrival, I think the OEM toyota part is a better value.

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[mtbtim]

Check out this video [MENTION=102606]infamousRNR[/MENTION] and I made for replacing the trans mount and engine mounts. We show a technique of how to check if the trans mount is bad. You're basically looking for a separation of the rubber from the metal plates. The mount is two rubber blocks sandwiched between two metal plates. The rubber is affixed to the metal plates on opposing sides. Over time, the rubber can become separated from the metal and/or the rubber mount can just crack or tear.

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