Transmission clunk - NOT 4WD

[RickyCRX]

My '03 V8 4Runner has around 81k miles and in the last couple of weeks just started making the 'bump' feeling when coming to a stop, or immediately after taking your foot off the brakes at a stop. It doesn't always do it, it's seemingly random. At first I thought it would do it just after hard stops, but it has done it after normal gentle stops as well. Mine's a 2WD model, so there are no grease fittings. My transmission and rear diff are running Amsoil synthentics in them and the fluids each have ~30k miles on them. I was already planning to change the tranny and the rear diff fluids in the next week or two anyways since they have 30k miles on them... I know it's a bit early to change synthetics, but I want this vehicle to last a long time and I do a decent amount of towing with it...

Has anybody else with a two wheel drive 4Runner had this issue? It seems that all of the posts of people with the clunk are with 4WD models, not 2WD.

It just concerns me a little bit, as I don't want to start having problems with the drivetrain on this vehicle.

Ricky

 

[toto]

That sounds exactly like the driveshaft/slip yoke problem that's known as "the clunk". I doubt it's a trans problem, but I don't know much about the 2WD powertrain. It's still rear-wheel drive, isn't it? If so, then you've got to have a driveshaft running to the rear axle. But no grease fittings?

 

[RickyCRX]

That is correct.. The vehicle is RWD, driveshaft running to the rear differential/axle. On the 2WD models, there are no grease fittings.

Ricky

 

[rx900]

That is correct.. The vehicle is RWD, driveshaft running to the rear differential/axle. On the 2WD models, there are no grease fittings.

Ricky

That seems strange. Its not the AC kicking on or off is it?

 

[TechWrench]

That sounds exactly like the driveshaft/slip yoke problem that's known as "the clunk". I doubt it's a trans problem, but I don't know much about the 2WD powertrain. It's still rear-wheel drive, isn't it? If so, then you've got to have a driveshaft running to the rear axle. But no grease fittings?

The 4wd drive shafts have the slip yoke in the middle of the shaft to allow for compression and expansion of the shaft as the suspension moves up and down because the shaft is bolted to flanges on the transfer case and differentials. The 2wd drive shaft allows for the compression and expansion by using a splined yoke that slides over the transmission output shaft. It is constantly lubricated by the trans fluid, so though it could be possible for the 2wd shaft to bind on the output shaft and cause the same type of thump, I would tend to doubt it.

 

[RickyCRX]

That seems strange. Its not the AC kicking on or off is it?

Nope, not the A/C... I haven't been using it for the last couple of weeks.

Ricky

 

[RickyCRX]

The 4wd drive shafts have the slip yoke in the middle of the shaft to allow for compression and expansion of the shaft as the suspension moves up and down because the shaft is bolted to flanges on the transfer case and differentials. The 2wd drive shaft allows for the compression and expansion by using a splined yoke that slides over the transmission output shaft. It is constantly lubricated by the trans fluid, so though it could be possible for the 2wd shaft to bind on the output shaft and cause the same type of thump, I would tend to doubt it.

The thump/clunk I'm feeling (can't really hear it) definitely doesn't seem to be as harsh as some of the 4WD owners describe it. It's almost like that feeling when the weather is cold in the morning and you back out of your driveway and don't pause between reverse and drive and the transmission kinda gives a little 'bump' before fully going into gear. This was discussed quite a while back last winter when the weather was cold and apparently a lot of people had that issue. This is very similar to it, only it happens when the vehicle has been left in drive and you just come to a stop and start back up again (or sometimes if you just barely creep forward).

Maybe I'll go through with this transmission fluid change now that my new order of Amsoil has arrived... I doubt it'll do anything, as the transmission fluid always stays nice and pink and doesn't seem like there's anything wrong, but it doesn't hurt to change it anyways.

Ricky