The Car Says "Clunk"

Regarding the gentleman who called into the show today with the car that would go clunk after coming to a stop. (don’t recall the type of car he had) It sort of reminds me of what my car will do on occasion. Sometimes after coming to a stop for a few seconds my car’s A/C compressor will kick on, kicking up the idle speed of the engine. From time to time I can hear my rear brakes grabbing harder as the car attempts to move forward because of the idle speed increasing. Could be that’s what he’s hearing also.

Both My suburban and my gm chassis rv make the same clunk as your caller describes … it definitely comes from the fuel tank. An easy way to eliminate the trans as the problem is to place the shifter in neutral as you come to a stop … this will remove the tension from the entire drivetrain and I’ll bet the clunk continues.

Gentlemen (and I use the term loosely!), another possibility is the rear yoke on said Jeep. Chrysler has a problem with clunking rear yokes back when we all had more brain cells and I had my sanity. As I recall there was a t.s.b. on them and it involved grease, cussing and sometimes replacing the yoke assembly.
It’s a thought.
I have to go now, time for my medications…

Marshall should check to see if the jack in his Jeep’s spare tire well is rolling around. My Jeep recently had the exact same clunking sound after coming to a stop. I traced the sound to the jack that is stored in the spare tire well under the mat in the storage area. In my Jeep there is a full service spare and a small, short and very heavy jack; both the tire and the jack are supposed to be fixed by a screw to a central bracket in the well. Apparently after the last time the spare was used, the tire and jack were not properly stored in the bracket and were therefore free to move around in the well. The jack would roll around every time I would come to a stop, and sometimes also it would move a bit on starting up again, just as Marshall described. I would recommend that he check that his spare tire and the jack are both securely fixed in place. Since I have properly secured the jack and tire in my Jeep, the clunking sound has disappeared.

I have a 2001 Toyota Tundra and it makes a similar noise after it comes to a complete stop. My car has disc on the front and drums on the back. The drums are not self adjusting and when they have gotten out of adjustment the car makes this sound. Does a Grand Cherokee have rear drums. If so adjusting these may stop the clunk.

I agree with fleecerdog and the senator. I believe this car was a Jeep with the 3 second delay clunk and felt like he was bumped from behind.
If the drive shaft yoke splines are dry and rusty this could stick in place w holding the suspension slightly loaded after coming to a stop. When the weight of the vehicle finally overcoms the stuck splined it shifts (telescopes) and goes clunk.
I am not sure if this vehicle has a telescopic splined drive shaft or a splined yoke on the trans output shaft.
I would pull the drive shaft and, clean and grease the splines and recheck for clunk/bump.

My 1989 4runner did the same thing. The spare tire was suspended on a little chain elevator that took a long thin rod and the jack handle to raise and lower. The tire would loosen up every 10k miles or so and start clunking every stop and on fast starts. The fix was a few cranks on the elevator chain and all was well. Until it got stuck in 2nd gear forever around 300k miles.

I have a 1999 Suburban. Over the years I have had this exact problem 3 times. It only occurs at stopping; about 3 seconds after coming to a complete stop it sounds as if a small vehicle has tapped my bumper, more sound but a slight feel. The fix has been easy - they grease the CV joint. It fixes it every time and I am not even charged! (No I am not a leggy blonde!). Good luck!

I had a 93 grand cherokee and it had airbrakes that did all sorts of strange things I’d ask Marshall if his brake pedal depresses further or pushes back on his foot at same time as sound. I don’t remember mine doing exactly what he says but the air would pump back up in the line once you stopped and make a sound. I’d check the air brakes.

I’m with “abiding dude”. Everything fits (including the clunk when he suddenly moves forward) if he has a large rolling object in the trunk! We took a new car back to the dealer for a similar clunk (with a delay of about 1 second), which turned out to be a bottle of Snapple that we had left under the passenger seat the first time we drove it!

I’m with “abidling dude” also… Marshall should check to see if the jack in his Jeep’s spare tire well is rolling around. Craig Hanson above has the best answer. Marshall didn’t give us the year of his Jeep so it might have side storage wells in the back that something is rolling around in. As a car dealer for 30 years you would be amazed to see what people have in their cars and leave in the car when they trade it in… SCARY trust me… :>)

Marshall, this is a well known Jeep problem. It is due to the insufficient lubrication of the splined shaft that goes from the transfer case to the yoke that is connected to the rear driveshaft. Normally, when the car accelerates from a stop, the rear wheels push forward, shortening the distance between the rear axle and the transfer case (which is fixed to the car frame). When braking to a stop, the rear brakes grab the wheels, and lengthens the distance between the rear axle and the transfer case. This back and forth motion is normally accomodated by the yoke and splined shaft as they slide back and forth over and into the other. When the lubrication is gone, the yoke will bind on the splined shaft, and there will be a delayed reaction of allowing the axle to find its equilibrium position. This delayed reaction is the clunk. Normally, the yoke/splined shaft will slide in and out as they are in rotation, but without sufficient lubrication, they cannot slip or slide when torque is transferred during acceleration and deceleration, which causes the binding. The cure is straightforward. The yoke/spline joint area is covered with a rubber boot with accordion pleats. The bands that hold the boot in place are removed, and the two U-joints on the rear driveshaft are taken apart so that the driveshaft can be removed. Be sure to match-mark both U-joints before disassembly so that they won’t be reinstalled out of phase. Clean, and then lubricate the splined shaft and yoke with automotive grease. Regular wheel bearing or chassis grease will wear out in 4 months with regular driving, and the problem will return. After much trial and error, I recommend only two greases, they are Lubriplate 3000 and/or Valvoline Palladium. These two are much more tenacious than regular grease and will tend to stay put and not be forced out so easily. Be super generous with the grease, and slather on as much as possible and still be able to put the boot back on.
Not only Jeeps, but some Ford and Toyota trucks also have this problem.

This kind of clunk could be caused by a lot of things, as mentioned above. Hopefully it will prove to be something simple to fix for the caller. But if not, here’s my 2 cents for what’s it’s worth:

I have a 1970’s Ford 4wd truck w/a similar clunk. I’m told it is a normal sound. It’s caused by the way the truck is designed, specifically by the limited slip rear differential slipping normally. Sometimes it doesn’t slip until a few seconds after the stop, when I notice a clunk and the car seems to move a bit. I sometimes notice a similar clunk on start up. And I notice an even more noticeable clunk when I put the truck in reverse. All this clunking is worse with an automatic transmission, and worse with higher idle speeds. If you notice this kind clunk and your vehicle has a limited slip differential, one thing you can do is make sure the idle speed(s) are set correctly.

If the clunking gets worse, that’s a sign – at least for my truck – that the one of the drive shaft u-joints may be failing (between the transfer case and the rear differential, usually it is one near the differential) . A mechanic can easily diagnose a failed u-joint, and they are fairly inexpensive to replace. Or it might be simply that the u-joint or the splined joint in the drive shaft needs a shot of grease. Oh, one more thing. If there’s been any work done one the differential, one other possibility is that the mechanic didn’t put in the req’d amount of friction modifier additive when they replaced the differential gear fluid.

“GeorgeSanJose” I guess great minds think alike. lol The thought of a u-joint also came to my mind when they were discussing this on the show.

I have another theory. I admit that it isn’t really likely, but it seems feasible to me. Consider it a plan D in case plans A, B, and C fail. I have a Saturn Vue that makes makes 3 putt noises from the tailpipe about 3 seconds after I come to a complete stop. What if the Jeep is making a single putt from the tailpipe after stopping? And what if part of the exhaust system was loose and banged against something else when this happened? Unlikely, but it could cause a clunk.

sounds like u-joint or needle bearing problem