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Please help to diagnose- asphalt/tar smell + Clunking


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OK- It is possible I have more than one issue going on...

 

I would have bet that these current noises were coming from the front- axle,suspension,or bearing related- but I am no "mechanical genius"...

 

Just seemed wierd, driving at a steady speed (like 60mph) let off the gas, sound diminished, put on the gas- (not enough to really accelerate) just "put it under load" (if that makes sense) tunk,tunk,tunk sound very pronounced.

 

Problem w/all the non-busy, roads around here, they are all done w/tar and pea gravel- hard to hear anything, but the crunchy gravel sound- but I'll try.

 

For the record, I do need rear brakes. Got the "warped rotor pulse" going on.

 

Which wheel has E-brake? (just one rear right?)

Would a bad bearing heat up the wheel? (fronts are not hot)

Edited by KaraK
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yes, a bad wheeling bearing will eventually cause the hub to get hot.

you say the fronts are not hot, how about the rears??

 

dragging brakes can also cause the wheels to feel hot

 

take it for a test drive, then check all 4 wheels for excess heat - if you find one that is warmer than the others, that is the one you need to be looking closely at.

 

hmmm, needs rear brakes? umm, mine makes a kind of grindy, thunky noise as it is in need of new pads on the back (have them, just need to get them on :o ) but with mine the noise is more pronounced at slow speeds - so...

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Jo- see PM.

Went for a drive today, (froze my a** off w/windows open) and think the noise starts around 45-50mph. hard to tell, on these rough roads. Was definately less pronounced, than 60mph on smooth highway.

 

Stuck calipers- been there, done that. I check wheel temps. just about every time I drive. Rears slightly warmer than fronts- but not hot, and nothing drastic. Am curious though, which has E-brake?

 

Really don't think this is the brakes, yes they have issues- but...

 

When I went onto that exit ramp, I was NOT braking at the time.

 

Just seemed wierd, driving at a steady speed (like 60mph) let off the gas, sound diminished, put on the gas- (not enough to really accelerate) just "put it under load" (if that makes sense) tunk,tunk,tunk sound very pronounced.

 

I am still unable to determine if it's engine or wheel speed related-sorry.

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...When I went onto that exit ramp, I was NOT braking at the time.

 

Just seemed wierd, driving at a steady speed (like 60mph) let off the gas, sound diminished, put on the gas- (not enough to really accelerate) just "put it under load" (if that makes sense yes it does) tunk,tunk,tunk sound very pronounced.

 

I am still unable to determine if it's engine or wheel speed related-sorry.

 

ok... not braking at the time...changes with very light load changes...i am beginning to lean toward something with the drivetrain (drive shaft/axle related) which could also be wheel bearings, altho - if you arent getting pronounced heat on one wheel - i kind of dont think it is wheel bearing...possibly U-joints??

 

oh, and on my car, the e-brake is both front wheels - yours may be different however...

Edited by heartless
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Just seemed wierd, driving at a steady speed (like 60mph) let off the gas, sound diminished, put on the gas- (not enough to really accelerate) just "put it under load" (if that makes sense) tunk,tunk,tunk sound very pronounced.

 

OK- I thought this comment^^^would've been a "smoking gun" for all of you that know more than I... But...

 

How's this for another piece of the puzzle...

 

Car pulls to the left upon acceleration...

 

Example...Driving along at 40 MPH. @ 1500 RPMs, step on it, to 2000ish RPMs, car pulls to the left, steering wheel pulls to the right...

 

Does any of this make any sense to anyone???

 

I am an ignorant F***, ready to take it somewhere, but don't want to be clueless as to the diagnosis... Thanks-K

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OK - I'm gonna suggest a differential stub has popped out partially and the seal is leaking too. Check the front diff oil level. Get under the car and examine the inner and outer boots and look for diff oil.

 

You know, it feels like something has "popped out" but I checked all fluids/boots a week or 2 ago, boots were dry, fluids OK. As I recall, diff oil was a little overfull when I bought it, and is now (as of 2 weeks ago)...

 

Pardon my ignorance, WTF is a "differential stub"???

 

I will go check anything right now, if it will help me finger this out...

 

Thanks!

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Thanks Dave- Both rears??? Haven't had them apart at all, yet... Anything special I need to be aware of- when I do them?

 

Got the fronts all fingered out. (Thanks to Tom...TheLoyale)

 

All I know is old GM's...

 

Yes, both rears. It's much like a GM drum brake inside the rotor.

 

Tough part is de-adjusting the Ebrake and the adjuster enough to get the shoes to clear the rust ridge.

 

Dave

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You know, it feels like something has "popped out" but I checked all fluids/boots a week or 2 ago, boots were dry, fluids OK. As I recall, diff oil was a little overfull when I bought it, and is now (as of 2 weeks ago)...

 

Pardon my ignorance, WTF is a "differential stub"???

 

I will go check anything right now, if it will help me finger this out...

 

Thanks!

 

 

 

 

I think your car is built like my wife's which has splined stubs sticking out from the front diff. The big axle cups are splined internally and slip over the stubs and are held in place by a spring pin. However, the stubs are held into the diff by a 'circlip' (w'ever) a circle of springwire in a groove. (IIRC)

 

Some of your initial symptoms seem to fit a scenario in which a 'hard' turn (to the lock) could have pulled on the stub enough to pop it loose - enough to compromise the diff seal - cause leakage of the fluid (which might blow back onto the exhaust) and maybe cause the smell (diff oil smells bad anyway - so it may smell different than engine oil if it got on hot exhaust) thuinking and other odd driveline sensations you report.

 

Doesn't mean any of that is correct, but it's something different to look for. (could be the previous owner got an axle that was too short - or, the stub was pulled out of it's groove just slightly when the old axle was pulled out, but your hard turn when reversing pulled it more, comprimised the seal, it bound-up and is now so far out of place is intermittently engaging internally)

Edited by 1 Lucky Texan
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Thank You to "I Lucky Texan"!! What car does your Wife drive?

Stuff you say makes sense to me... (Correct or not)

All of this started when Spouse used the car for pizza deliveries...

(Of course... all was fine...) I cannot say what may have occured...

Does this diagnosis depend on a visible leak of gear lube? I will continue to monitor levels- but see no "visual evidence" at this time...

I do know, that both front CV axles are Napa aftermarket replacements, which no-one on here likes...

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Yes, You may ask...

The previous owner installed them in Oct.2009 w/103,827 miles on the clock... He was a traveling salesman- they were installed in Alabama... He and I, both live in Wisconsin- within 20 miles of each other...

I know enough to research my purchases-(care about my car) apparently he did not...

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Thank You to "I Lucky Texan"!! What car does your Wife drive?

Stuff you say makes sense to me... (Correct or not)

All of this started when Spouse used the car for pizza deliveries...

(Of course... all was fine...) I cannot say what may have occured...

Does this diagnosis depend on a visible leak of gear lube? I will continue to monitor levels- but see no "visual evidence" at this time...

I do know, that both front CV axles are Napa aftermarket replacements, which no-one on here likes...

 

 

Yeah, sry, my wife drives an 03 H6 Outback wagon. I recently did some work on it and one repair was an axle replacement due to split inner boot.

 

My car is an 06 WRX wagon.

 

If the smell comes and goes, it might mean that sometimes the seal on the front diff is leaking and sometimes not. If possible, lift he front of the car, secure on jacks, and turn the wheel all the way left, then check the left inner axle joint. the (probably green) 'cup' part should stay in the same position and not shift in-out more than , maybe, a 2-3 mm. maybe someone else here can confirm that. Then, check the right side after turning the wheel all the way to the right.

 

I should also mention that, it's possible grease could be pushed out either end of a rubber boot. Particularly on a rebuilt axle. If it was over-greased or the bands are not tight, etc. That also might happen during or after extreme turning of the wheels when the boots are stretched/compressed a lot. They wouldn't have to be split to deposit some grease onto the exhaust. The 'split boot problem' just happens frequently because the inner boots are exposed to so much heat from the exhaust pipe.

Edited by 1 Lucky Texan
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  • 2 weeks later...

Thank You again, to "1 Lucky Texan"- I wasn't able to get back on here for a while...(wow it looks different)

 

I haven't -smelled the smell- since "the spouse" used my car to deliver pizzas. The other symptoms are getting worse/more noticable though...I'm hearing the tunk tunking at lower speeds, and I now feel pulling at every shift (change of RPM).

 

I haven't been under the car for a week or two- but, didn't see any residue that would have led me to a clue as to leakage...

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Thank You again, to "1 Lucky Texan"- I wasn't able to get back on here for a while...(wow it looks different)

 

I haven't -smelled the smell- since "the spouse" used my car to deliver pizzas. The other symptoms are getting worse/more noticable though...I'm hearing the tunk tunking at lower speeds, and I now feel pulling at every shift (change of RPM).

 

I haven't been under the car for a week or two- but, didn't see any residue that would have led me to a clue as to leakage...

 

 

Check the level in the front diff - the stick on the other side from the transmission dipstick. It's short, down low, and often covered in 'muck'.

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  • 3 weeks later...

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