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Trunk Monkey

Vibration in the Gas pedal at 35-40 MPH only

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Ok trying to trouble shoot this in my 2011 JKU;  I recently started feeling a vibration in the gas pedal starting at 35 mph and continues through 40mph and then stops.  I also notice a distinct "hum" at that time.  The ABS Light and Traction light just came on (steady) yesterday as well.  Doesn't seem to matter what RPM range I'm in at the time, it seems to be speed related.  I just rotated the tires today to rule that out and its still doing it.  I didn't drop the front driveshaft BUT It's an Adams that's less than a year old.  I replaced both hubs with Timken's when I did my RCV's and Reid knuckles etc at Brians a little over a year ago.  I'm thinking its not just the wheel speed sensor due to the vibration in the pedal?  Is it possible one of the hubs went bad already?  Haven't been in mud in years and no real hard wheeling since RTC? Thoughts

Thanks

Brian

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28 minutes ago, Trunk Monkey said:

Ok trying to trouble shoot this in my 2011 JKU;  I recently started feeling a vibration in the gas pedal starting at 35 mph and continues through 40mph and then stops.  I also notice a distinct "hum" at that time.  The ABS Light and Traction light just came on (steady) yesterday as well.  Doesn't seem to matter what RPM range I'm in at the time, it seems to be speed related.  I just rotated the tires today to rule that out and its still doing it.  I didn't drop the front driveshaft BUT It's an Adams that's less than a year old.  I replaced both hubs with Timken's when I did my RCV's and Reid knuckles etc at Brians a little over a year ago.  I'm thinking its not just the wheel speed sensor due to the vibration in the pedal?  Is it possible one of the hubs went bad already?  Haven't been in mud in years and no real hard wheeling since RTC? Thoughts

Thanks

Brian

Same symptoms and same speed range as I had, it was tire balance.

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Same symptoms and same speed range as I had, it was tire balance.

 

Wouldn't a tire rotation rule that out since the rears are now on the front? I did a 5 tire rotation today. 7bcf4d4df45499ed435923d3cc4a3071.jpg

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1 hour ago, Trunk Monkey said:

Ok trying to trouble shoot this in my 2011 JKU;  I recently started feeling a vibration in the gas pedal starting at 35 mph and continues through 40mph and then stops.  I also notice a distinct "hum" at that time.  The ABS Light and Traction light just came on (steady) yesterday as well.  Doesn't seem to matter what RPM range I'm in at the time, it seems to be speed related.  I just rotated the tires today to rule that out and its still doing it.  I didn't drop the front driveshaft BUT It's an Adams that's less than a year old.  I replaced both hubs with Timken's when I did my RCV's and Reid knuckles etc at Brians a little over a year ago.  I'm thinking its not just the wheel speed sensor due to the vibration in the pedal?  Is it possible one of the hubs went bad already?  Haven't been in mud in years and no real hard wheeling since RTC? Thoughts

Thanks

Brian

I know the 3.6L has a drive by wire throttle and I thought the 3.8 did as well.  So, not the gas pedal per se.  Did you see if the Adams shaft threw a weight?

Time for these:

BD_Wheel_HR.png?itok=ajDz-bzY

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Pull the drive shaft first and see what happens. While your at it check and see if the front pinion nut is loose.

Pissing off my wife since way back

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1 hour ago, Trunk Monkey said:

 

Wouldn't a tire rotation rule that out since the rears are now on the front? I did a 5 tire rotation today. 7bcf4d4df45499ed435923d3cc4a3071.jpg

Not if all 5 are out of balance.   Mine were all horrible after RTC

 

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Pull the drive shaft first and see what happens. While your at it check and see if the front pinion nut is loose.

Pissing off my wife since way back




I'll try that tomorrow

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If you put the Jeep in neutral while it's doing it does it go away?

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If you put the Jeep in neutral while it's doing it does it go away?

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Yup still there when in neutral and at those speeds

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Well unit bearing. I just went through diagnosing my F250 and just something so simple helped me narrow it down

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Well unit bearing. I just went through diagnosing my F250 and just something so simple helped me narrow it down

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Just checked, they're less than 6 months old?

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Just checked, they're less than 6 months old?

I don't think it would be your driveshaft or power train related since it happens even in neutral.
If the unit bearings are okay and you did a tire rotation and have brand new RCV's could it be any of the joints. I know unfortunately that's a decent amount to check but even though it's not death wobble I'd say treat it like it is and just check joint for S's and G's.

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I don't think it would be your driveshaft or power train related since it happens even in neutral.
If the unit bearings are okay and you did a tire rotation and have brand new RCV's could it be any of the joints. I know unfortunately that's a decent amount to check but even though it's not death wobble I'd say treat it like it is and just check joint for S's and G's.

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Stuff is still spinning.

Pissing off my wife since way back

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Stuff is still spinning.

Pissing off my wife since way back


Stress is placed on the joints while accelerating and free spins when there is no acceleration with minimal stress. And generally bad driveshafts with U joints make a clunk at first when you accelerate.

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Stress is placed on the joints while accelerating and free spins when there is no acceleration with minimal stress. And generally bad driveshafts with U joints make a clunk at first when you accelerate.

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I'm going to have to disagree with you. Every front drive shaft that I had go out of balance was do to a worn slip yoke. The drive shaft needs to be pulled and we'll go from there.

Pissing off my wife since way back

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I'm going to have to disagree with you. Every front drive shaft that I had go out of balance was do to a worn slip yoke. The drive shaft needs to be pulled and we'll go from there.

Pissing off my wife since way back


That's cool. And I very well maybe be wrong and might learn something. No biggie. All here to help.

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15 hours ago, jkbroc said:


Stress is placed on the joints while accelerating and free spins when there is no acceleration with minimal stress. And generally bad driveshafts with U joints make a clunk at first when you accelerate.

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I agree with this.

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Stuff is still spinning.

Pissing off my wife since way back




S's and G's?? When we redid the front end 6 months ago, I did a new synergy drag link and trackbar along with the sector shaft brace and track bar brace, and even new dynatrac BJ's. The only existing part that went back in was the synergy TieRod?????

I'm going to drop the driveshaft tomorrow and check the pinion nut like rich said just to absolutely rule that out.

If it still happens, Then I may head over to Tire Tech to have the tire balances checked.

After that, I'm going to assume I got a lemon of a unit bearing from Timken and Rick auto.

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17 minutes ago, rich6700 said:

Drive it with the drive shaft out.

Pissing off my wife since way back
 

yeah that's the plan, that's how I found out that the dealer killed my stock one when they replaced the torque converter.  

 

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I'm thinking it's gonna be Tire balance. It was less noticeable almost nonexistent in the pedal today and slightly quieter hum between 35/40 since I did the tire rotation.

I dropped the front ds just to be sure and it didn't change at all. Torqued the pinion nut again as a precaution. Going to have the tires checked and rebalanced if necessary tomorrow.

I think the ABS and Traction control lights are just a coincidence and unrelated. I think I stretched the front p/s wheel speed sensor at RTC. It was tight AF when I checked it and the retaining bracket was bent. I have a spare I'll throw on tomorrow and see.

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Just as I thought, replaced the front passenger side wheel speed sensor with an old (but good) one that I had hanging in the garage and before I drove 50 feet the lights went out.  The hum and vibration are still there at 35-40 but slightly, I'm going to let Gina drive it to work all next week and see if wearing in the tires after the tire rotation that I did a few days ago (about 7,000 miles since the last rotation) makes a difference before I take it in to have the tires rebalanced.

 

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You can't let your tires go that long without rotating them. I find that the tires start to get a little choppy when you go that long. I rotate mine at every oil change ( 5000 miles).

Pissing off my wife since way back

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You can't let your tires go that long without rotating them. I find that the tires start to get a little choppy when you go that long. I rotate mine at every oil change ( 5000 miles).

 

Pissing off my wife since way back

 

 

 

 

Think the noise will go away once the fronts are worn down some???

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