Thumping feeling, tire? speed sensor? | Ford Explorer Forums - Serious Explorations

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Thumping feeling, tire? speed sensor?

jmwkdw07

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Joined
February 21, 2010
Messages
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City, State
Illinois
Year, Model & Trim Level
2002 XLT
I am new here and have read other posts and searched here and to no avail i cant seem to find an answer!
I have a 2002 xlt 4x4 explorer. On deceleration, I get a thumping sensation felt in the whole vehicle a grinding noise, actually sounds like a bunches of crickets chirpping! This all started after i had the front tires and hubs replaced! when i put in neutral it still does it until i turn off the ignition switch all the way and it coasts nice and smooth no noise or thumping no nothing?:mad:
 



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Wonder if it might be a motor mount if it is only doing it when the engine is running. Or one your idler pulleys binding on your belt. Does the thumping stop when you are at idle?
 






just at deceleration! It starts after I reach about 30mph and i let off the gas.
If i shift to nuetral and leave the ignition on it continues but if i turn off the ignition it stops and coasts fine, i can then start it back up and shift to drive and it drives fine until i decelerate again??
 






Hmmm. I'm a bit stumped on this.

So, if you accelerate up to 30, let off the gas it begins to thump, grind and chirp and only stops if you shut the engine off?

By default I would attribute the thump and noises to your driveline, but based on what you describe we can rule that out. But, silly question, your ABS light doesn't happen to be on? Only reason I ask is that you mention the bearings were recently replaced. If your ABS light is on it could be one of the new bearings or one of the sensors being faulty or not connected. Not completely sure on the '02 as my expertise is on the 2nd gens.

What happens if you decelerate completely to a stop without shutting the engine off, do the noises continue at a complete stop with the engine running? Is the thumping a noise or something you actually feel?

Also, have you tried turning your fan on and off on your heat/ a/c and also making sure the defroster is off so the a/c is not running? It may also be the blower motor.

Have you revved up the engine in park and let off the gas and see if you can duplicate the noise or is it only happening out on the road?

Off the cuff, I'm thinking it must be one of the pulleys on the a/c, waterpump, oil pump, power steering pump, or one of the tensioners, etc, or possibly the blower motor. Under acceleration, you may be placing enough tension on the belt and pulleys to stop the noise.

BTW, which engine and drive system do you have in your '02?
 






ok to start with, when i come to a complete stop or slow to under 20, it runs fine. the thumping I can actually feel, its sort of like a jerking or running over speed bumps, Its a 4.0 V6 with auto trans and 4x4. the only light is on is the check engine light which just came on a week ago, but the thumping has been happening since july! the 4 ford mechanics that has driven it are puzzled and it does not return any error codes. but a couple of them have tried to engage 4 wheel high and its starts making terrible grinding noises. i dont have the money to have them tear into it as they say they need to do. I dont think it is a mechanical issue since it quits when the ignition is turned off. I could be wrong!!?
 






ok, I'm not 100% sure this is your problem but.... Has anyone checked the wheel speed sensors? I had a front wheel bearing replaced once and suffered some strange jerking and rubbing/almost grinding noises. No check engine light to help me out. After poking around I found the wire for the wheel sensor came uncliped (or was never cliped) and was worn through by the tire. What was happening was the truck was getting intermittent signals from the sensor, sensing false wheel slip, and keep trying to engage 4wd. Had the sensor replaced and the problem went away. This could be your causing your noise. When you coast without the ignition on there's no signal from the wheels so no thumping. The terrible grinding may be damage to the transfer case.
You said your Check engine light came on - did you have the codes read?
 






Yes definitely follow the connectors in from the hubs and make sure the are in fact connected and/or not worn through.

Since your 4WD is automatically controlled, I am assuming you have the "auto 4 X 4" as the default switch and then your 4 High and 4 Low options, shutting the engine down may actually be deactivating both the speed sensors and hence the 4WD engagement.

Since you are experiencing drivetrain noises when the 4 X 4 is locked, it is either the tranfer case or front differential making the noise, or both.

Are all 4 of your tires a match, i.e. same size and brand and evenly worn? I think you mentioned you replaced two tires recently, not 4.

If you have the "auto" 4wd setting as your default and not a true 2wd setting, the new tires are most likely the cause of this problem. The auto mode detects wheel slip and engages even on dry pavement when needed to eliminate wheel spin. If you have unmatched tires, 2 are more worn than the other which is causing the AWD to kick on an off constantly because of the mismatch (different circumfrence of tire due to wear) and causing a lot of stress and wear on your drivetrain. Your tire shop should have warned you about this and recommended replacing all 4 tires.

My next recommendation is such, if you are the least bit mechanically inclined, try removing the front driveshaft and see if the noises stop. Makes sure you park on a level service with the parking brake on with the driveshaft out as the vehcile may slowly roll without the shaft in there. Also, check the fluid level and condition of both your front differential and transfer case. All you need is a 3/4 ratchet driver to remove. The diff fluid should tan/brownish in color and the transfer case should be pinkish red (auto trans fluid). Check both the fill caps for metallic flake on the backside, a little bit of very fine metal is normal, small chunks of metal are not (they are magnetized) and actually smell both fluids for a burnt smell. The diff fluid by default stinks to high heaven, but smell for a burnt odor.
 






I have an 03, 4.6L. My problem I "had" almost sounds similar. The place I could feel it most was probably under the driver seat. It seemed when I reached around 50mph, then decided to slow down then I could feel a clunking through the drivers seat. If I stayed under 50 or so the clunking would never appear. The end result was my tires. According to specs. there should not be more then 3/4" difference in circumference between any given tire. Luckily I was going to replace my tires anyway so I put (4) new tires on and the problem went away. Come to find out I had one tire that was over an inch different in circumference then the other three. The truck was that way when I bought it. You might have a tire issue. Just my 2 cents.
 






Sounds like Tire problem, especially if you only put 2 tires on. You must 4 equal circumference tires or you will wreak havoc on the driveline. It amazes me how many customers think its ok or try to save money by just replacing 1 or 2 tires. Ends up costing thousands in the end for driveshafts, trnsfercase and front diff replacements.
 






Sounds like Tire problem, especially if you only put 2 tires on. You must 4 equal circumference tires or you will wreak havoc on the driveline. It amazes me how many customers think its ok or try to save money by just replacing 1 or 2 tires. Ends up costing thousands in the end for driveshafts, trnsfercase and front diff replacements.

Reread the OP. The problem goes away with the ignition off and the truck still moving.
Still betting on a wheel sensor. No ignition = no electrical = no sensor involvement = no issue.
 






I am getting 4 new tires this friday, I hope that the problem!

the front tires were replaced the same time as the front hubs at my local ford dealer and they never said anything about the tire size thing! and niether did the other ford dealers!!? my local tire dealer informed me of the difference in tire sizes and what happens with auto 4x4's

let you know what i find out
 






Shoot. Missed the part about you having new tires the same time as the hubs.
 






I cant believe how the tires could have caused all the problems!!?? the tires fixed it all
 






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