Question about thump when at a stop and let off the brakes.

[wtf6316]

It does this every once in a while. When you are at a stop and let off the brakes slightly I feel a thump like someone hit me. I asked the orig owner and they took it in several times and the dealer said everything was normal. Its still under warranty so Im takeing it in. Any one else had this happen? Also It fells like it wants to go as soon as I let off the brakes like im on the gas slightly.

 

[CJ3Flyr]

It may have happened to one or two other members.:bash: This thread, which includes 630 posts, talks about it. Keep the driveshaft lubed and it'll be minimal but never go away.
http://www.toyota-4runner.org/showthread.php?t=975

 

[wtf6316]

Thanks for the link. Ill lube it as soon as possible.

 

[CJ3Flyr]

Thanks for the link. Ill lube it as soon as possible.

Take care to not 'over-grease' the rear slip yoke... It can cause damage as the grease can't compress.

 

[Frown]

I havent checked out the link for the thread, but just in case that doesn't help you, I have had a problem like this in the past with a Ford Explorer. It was a loose tranny mount. My sister recently had a problem like this and it was a motor mount on her Pontiac. Just my 2 cents. Good luck.

 

[sant6236]

In my opinion this is a result of stopping quicker than the transmission can shiftdown to its appropriate gear. Its actually a good thing. Imagine of the transmission shifted to a lower gear as quickly as we do stop. The tranny would be toast in a month.

 

[EEtM33t]

This happens quite often here and I find it thoroughly annoying... I ask that the drive shaft be lubricated each time I am at the dealership for an oil change and sometimes it makes a difference sometimes it does not...

 

[Zinarac]

In my opinion this is a result of stopping quicker than the transmission can shiftdown to its appropriate gear. Its actually a good thing. Imagine of the transmission shifted to a lower gear as quickly as we do stop. The tranny would be toast in a month.

That is the same observation I have made. My 4Runner feels the thump only when I have to stop quicker than normal. I don't think it is a big deal, but it can be annoying.

 

[woodyc]

Is this problem of clunking unique to only 4 wheel drive models or is it experienced on 2 WD models as well?

 

[SpaceNeedle]

this is totally normal and it happens so often to so many folks i dont' even care about it

greasing it every oil change is just a poor bandaid. there's no fix for this.

 

[TechWrench]

In my opinion this is a result of stopping quicker than the transmission can shiftdown to its appropriate gear. Its actually a good thing. Imagine of the transmission shifted to a lower gear as quickly as we do stop. The tranny would be toast in a month.

The driveshaft clunk has nothing to do with the transmission. It happens when you brake hard because you are causing a weight shift which makes the rear pitch forward and up. This motion results in what has been called axle wrap, and because of the design of the rear drive shaft slip joint on the 4wd models, the slip joint expands as the rear axle shifts. When you let off the brake and start to accelerate, the rear axle returns to its normal position, and the drive shaft slip joint has to compress. Because the tolerances in the slip joint are so tight, the joint resists the compression and then releases with the thump we all feel. If you have read any of the threads on this, the simple, temporary fix is to keep the drive shaft slip joint lubricated on a regular basis. Some have reported removing the drive shaft, disassembling the slip joint and cleaning all the old grease from the splines and applying new grease has worked for them. Others have had the dealerships replace the drive shaft, in some cases several times, with varying degrees of success. I choose to not let it bother me. I lubricate the slip joint as often as I think of it, and if it happens, I know it isn't dangerous or damaging, and live with it. My choice.............

 

[TechWrench]

Is this problem of clunking unique to only 4 wheel drive models or is it experienced on 2 WD models as well?

To the best of my knowledge, it only happens with the 4wd models. The drive shaft on the 2wd models is a different design, with no integral slip joint, so it doesn't have this problem.

 

[latreto]

I think the thump is more notorious when you have the air conditioner working, and is related with the start of the compressor. When the compressor starts it put weight to the motor and this increases the idle speed.

Rafael

 

[HOJeepster]

This happens to me as well. I think its a tranny deal.

 

[latreto]

it is a normal thing in this model. Do not waste your time taking it to service.
I already wasted mine, and Toyota said it is normal.
I have checked that it is related to the heater/cooling system, specifically when the compressor (air conditioner) connects and disconnects.

Rafael

 

[TechWrench]

it is a normal thing in this model. Do not waste your time taking it to service.
I already wasted mine, and Toyota said it is normal.
I have checked that it is related to the heater/cooling system, specifically when the compressor (air conditioner) connects and disconnects.

Rafael

This thread is discussing the thump/clunk in the drive train, specifically the drive shaft slip joint. It is in no way is related to, or caused by the heater/cooling system. The only result from the A/C compressor cycling on/off would be a slight change in the engine idle speed to compensate for the additional load the A/C compressor would exert on the engine at an idle. We have been discussing, at length, about how lubricating the slip joint in the rear drive shaft on 4wd models seems to alleviate the thump/clunk for a period of time. How would any A/C compressor related event effect the slip joint in the rear drive shaft?

:ybrick:

 

[latreto]

My apologize. I miss understood the point.

I thought this thread was about the little thump (like someone hit you slightly from the rear) that sometimes is felt when stopped in a traffic light or stop signal. This symptom is particular to this model and is normal.

Regards

Rafael

 

[jcxny]

Yup I have the same problem also, 4 WD , sports Edition

 

[Mtn.Rush]

Yup I have the same problem also, 4 WD , sports Edition

Yup me too, 4wd Limited.

 

[nefarious]

Appreciate the info. I've got the same thing in my 07 Limited 4wd v8 and was wondering about it.