This sound sounds expensive...

[TORCH]

Today while deep in the backcountry after a steep hill climb and descent I started to notice a slaping/clapping/clunking sound that resembled the sound a large screw would make if lodged in a tire just much louder and there is nothing in my tires. It increases as speed increases and is definitely rotational in frequency. I was able to get back off the trail which required some heavy 4wheeling and was able to drive my truck home 20 minutes on the freeway. It sounds bad, it's loud and I cannot figure out the origin of the sound. I can tell you this: It gets louder when in Drive than in neutral when coasting down the road, it gets louder and increases in frequency with each rotation of the wheels. It happens in reverse, Low, 2nd, 3rd, 4th, 5th gears. All functions of the transmission and TC are working such as 4HI, 4 LO, center diff lock, and will shift through all gears. I checked my drive shafts and they seem fine. All wheels rotate without sound when jacked up and put in neutral. the sound continues with brake pedal pushed while accelerating. The sound does not happen in park, and not when moving. Not parts on the car are excessively hot, leaking fluid, smoking, or anything like that. I pulled all the wheels off, none of the calipers are loose, brake pads are all okay. I'm thinking It must be something in the driveline, transmission or transfer case. Does anyone have any ideas before I take this thing to the shop? I almost never let anyone work on my truck if I can do the work myself but I cant figure this one out. Thank you very much for any help you can offer.

 

[birdmann]

CV shaft is probably broken.

 

[Fern]

+1 for cv failure

 

[TORCH]

CV shaft is probably broken.

That would be unfortunate as I just replaced both of them in the last 6 months. Would my truck have been able to drive up and down some pretty steep terrain with a broken CV? It's possible I broke one because I had the truck jumping a bit using atrac to get up an obstacle but it wasn't anything that crazy. Anyways what is the best test to check for a broken CV? I've only replaced them when it was obvious- like a torn boot and a clearly broken shaft. Thanks!

 

[Fern]

I would start by jacking the front up and rotating the front tires.

 

[TORCH]

I would start by jacking the front up and rotating the front tires.

hey sorry you may not have read through my long initial post but I did jack up the front, put it in neutral and spun the tires on both sides as well as from the front drive shaft. Didn't notice anything out of the ordinary but I will try it again tomorrow and look more closely. One other thing it seems to be doing is a slight lunge forward, just slight, when in drive moving around 5 mph. this coincides with the clunking sound.

 

[NJshadow93]

If it was a broken CV shaft you wouldn't be able to drive it at all (ask me how I know). A strong possibility is that you got mud in the boot though and that's the source of the noise if it is CV related. Check the clamps on the boots to make sure they are there/tight/intact. I heard this same noise briefly (only for about a mile) after some heavy mudding and then I blew the half shaft on a trail a week later.

 

[Plumber]

Could be a CV problem like stated above or maybe a popped ring gear. Done it before in another vehicle and had the same symptoms.

 

[gm350reratliff]

Could be a CV problem like stated above or maybe a popped ring gear. Done it before in another vehicle and had the same symptoms.

I agree with this^^

Have you tried jack stands at all 4 corners and use the engine to take wheel speed up? Also, you can very lightly use the brakes to simulate road resistance. Be sure to disable VSC and traction control before hand.

 

[macgyver_ga]

Check your driveshaft U-joints again for slop. When my U-joint went bad on my old taco it started as a click/pop only at starting off from a stop, then gradually increased to constant noise within a day, then the following day I started getting bad driveline vibes.

Luckily a u-joint is a relatively cheap fix. $25 for the part and takes less an hour to fix.

 

[TORCH]

I agree with this^^

Have you tried jack stands at all 4 corners and use the engine to take wheel speed up? Also, you can very lightly use the brakes to simulate road resistance. Be sure to disable VSC and traction control before hand.

will using the center diff lock take care of VSC and trac control?

 

[NJshadow93]

will using the center diff lock take care of VSC and trac control?

Just pull the plug from the master cylinder. Locking the center diff will just disable VSC but not traction control.

 

[TORCH]

So I got it jacked up, let it go in drive and was able to localize the knocking to the rear differential. I put my hand on the differential and could feel the knock. The drive shaft and U-joints all looked okay and didnt have any play. So now the question is what could this be that would have allowed me to drive under serious load for miles and then drive for 20 miles on the highway? thanks for your help guys.

Also, to be move descriptive it sounds like someone knocking on a piece of wood with their knuckle coming from the rear diff.

 

[gm350reratliff]

Sounds like the ring gear is missing some teeth. Pull the fill plug, maybe you can see it with a pen light (or boroscope if you have one). Could also be a broke spider gear as well. Now is good time to re-gear.

 

[KidVermicious]

You're right, it's gonna be expensive . Sounds like you broke a tooth. Pulling the third yourself is pretty easy stuff, and will tell you exactly what's wrong.

 

[TORCH]

If it does turn out to be the ring gear how difficult of a fix is it? I've never done much with gears. Should I put a better ring and pinion in so this doesn't happen again? I'm really not sure what caused it as I wasn't doing anything abnormally crazy when it happened but I did have it in 4LO in Low gear going up the hill. Something weird I did notice was a few weeks ago the rear diff seemed to be leaking slightly at the housing facing the drive shaft. I thought it was a clogged breather so I cleaned it and then never had a problem until this. Do you think this could be related?

 

[gm350reratliff]

If it does turn out to be the ring gear how difficult of a fix is it? I've never done much with gears. Should I put a better ring and pinion in so this doesn't happen again? I'm really not sure what caused it as I wasn't doing anything abnormally crazy when it happened but I did have it in 4LO in Low gear going up the hill. Something weird I did notice was a few weeks ago the rear diff seemed to be leaking slightly at the housing facing the drive shaft. I thought it was a clogged breather so I cleaned it and then never had a problem until this. Do you think this could be related?

Probably not related. Could be stress from a prior event that may just fractured it until now. I would pull the fill plug to see if you can pin-point the problem by spinning the ring gear. If not, drain the gear oil and look for metal chunks.

I've exploded a rear diff (chevy 10 bolt) just taking off normally from a stop light. Of course, the weekend before I was making my way down a very muddy rocky trail, loaded with fire wood. I probably hurt it that weekend but it didn't show its ugly head for a week.

 

[TORCH]

Probably not related. Could be stress from a prior event that may just fractured it until now. I would pull the fill plug to see if you can pin-point the problem by spinning the ring gear. If not, drain the gear oil and look for metal chunks.

I've exploded a rear diff (chevy 10 bolt) just taking off normally from a stop light. Of course, the weekend before I was making my way down a very muddy rocky trail, loaded with fire wood. I probably hurt it that weekend but it didn't show its ugly head for a week.

if it is the ring gear what would you expect for cost of repair? $800? Also, besides potentially re-gearing is there any difference in what ring and pinion I have put in for replacement? I'd like to avoid this again if possible.

As far as regearing goes...can you regear the rear without regearing the front? and if I plan to run 285s in the future but drive a lot on the highway should I stick with 3.73s or move up? Thanks!

 

[Kayden]

I had a similar sound the other day and couldn't figure out what was wrong but finally my brain kicked in and it turns out to be I left my e brake on. Yeah, stupid and silly me - I blame Toyota and I totally hate the e brake location and would prefer a lever style hand brake. While driving it sounded horrible and I pulled over several times to check for mud and/or rocks in my tires but nothing but finally stupid e brake came to mind.

This might not be your issue but I had a horrible similar sound that occurred and turned out it was my e brake being left on. This may not be your issue or anything similar but just in case I thought I'd throw it out because after 3 years I'm still not use to the stupid e brake location. Lol

 

[gm350reratliff]

if it is the ring gear what would you expect for cost of repair? $800? Also, besides potentially re-gearing is there any difference in what ring and pinion I have put in for replacement? I'd like to avoid this again if possible.

As far as regearing goes...can you regear the rear without regearing the front? and if I plan to run 285s in the future but drive a lot on the highway should I stick with 3.73s or move up? Thanks!

If you DIY, $800 may cover it. I would recommend you talk to these guys to find out more regarding options: East Coast Gear Supply

You could regear just the rear but you would have to remove the front drive shaft. If you were to use 4x4 with different front and rear ratios, it would bind up like crazy and probably break something. To do it right, you have to regear the front and the rear together.