4Runner severe “shudder”

[DGMAX99]

New intermittent problem which started recently.

Have a 2003 4Runner V8 4/all wheel drive that had developed a severe (when it happens) “shudder”, kinda like running over the cut asphalt shoulder warning strips. It randomly happens when the vehicle is under power. I have not been able to tie it to any specific condition or time yet. All I can say is the best I can tell it appears to quit when the gas pedal is released. Checked the automatic transmission fluid and found it to me normal.

Has anyone else experienced anything like this?

Thanks!

[Brian R.]

Have you had any recent repairs done on the drivetrain?

Are the propellor shafts adequately greased? Have the differentials been serviced?

[DGMAX99]

No recent major repairs... Everything greased and levels checked last oil change (few months ago, I typically do my own maintenance) but this is something I can easily do again...

Any other ideas what it might be?

Thanks

[Brian R.]

Are all your tires exactly the same size and age? Have you retorqed the propellor shaft bolts? Original wheels? Have you checked the transfer case fluid? Replace the fluids in the transmission and transfer case and differentials?

Can you remove the front propellor shaft and run in just 2WD - see if the vibration is still there? Remove the rear propellor shaft? (Mark them to replace them in exactly the same position as original).

[DGMAX99]

Originally Posted by Brian R.

Are all your tires exactly the same size and age?

Yes

Have you retorqed the propellor shaft bolts?

Not recently but will when I recheck the fluid levels and re-grease.

Original wheels?

Yes

Have you checked the transfer case fluid?

Yes but will recheck

Replace the fluids in the transmission and transfer case and differentials?

Actually, yes but it’s been about a year and a half or more.

Can you remove the front propellor shaft and run in just 2WD - see if the vibration is still there? Remove the rear propellor shaft? (Mark them to replace them in exactly the same position as original).

Thats a possibility. If the issue gets more prevalent I will keep that in mind as a way to isolate it down.

[fourwd1]

Check the lower u-joint on the rear drv shft. May have to pull it off to check properly.

[DGMAX99]

I'll add that to the list, right now the vehicle is parked until I can find time to check it out (working a lot of overtime... )

[DGMAX99]

OK, getting this narrowed down a little more... Checked all the fluids, re-greased all zerks and checked everything accessible for tightness. Everything checked OK.

Since my wife is the one that pointed out this issue (it is a common occurrence for her but I have only heard/felt it once for about 2 seconds) I decided to drive the 4Runner to work a couple times (about 60 miles round trip with a variety of speed and road conditions).

I have determined that the condition appears to only occur when the RPMs are very low (below 1500rpm) and transmission is in 5th. The only way I could duplicate the occurrence is to let the vehicle accelerate as necessary to shift into 5th and then feather the throttle enough the bring the speed down to around 45mph. At this point the RPMs are slightly above 1000RPM. This is the point where the vehicle will “shudder” like the motor is “lugging”. I can keep the speed/throttle steady and manually shift to 4th and the shudder immediately stops.

While I can understand the motor lugging at this very low RPM range, it has not acted in this manner before. I suspect the transmission was previously shifting to 4th when it sensed the low speed condition. This all leads me to think the problem is tied to whatever senses the proper shift points.

I am not that familiar with Toyota automatics as this is the first one I have owned, I’ve always be partial to manually transmissions.

Does anyone have any knowledge of what would cause the change in shift patterns and/or what I need to check/replace?

Thanks!

[Brian R.]

That engine that year was coupled to a new transmission. Look to see if there are any TSBs for this condition. I am not very familiar with that transmission.

That particular combination of speeds causing the lugging indicates to me that the problem may lie in the torque converter lock-up mechanism is not disengaging. If the torque converter lock-up is not disengaging, it should also have this effect at any higher speed than you used to cause the lugging when you then slow down to 45 afterward.

As with all the Toyota transmissions, the coolant temperature sensor would influence shift patterns.

I don't understand why the engine should lug at 1000 rpm - this is after all a truck engine. Check the engine mounts. Plugs?

[badass335]

Just curious if you guys had any resolution to this issue? We are going through the exact same issue right now!

[DGMAX99]

Originally Posted by badass335

Just curious if you guys had any resolution to this issue? We are going through the exact same issue right now!

You'll get this in a PM also...but just in case...
Well, not really, it seemed to "go away" on its own. May have just been driven habit changes, not real sure. We ended up trading the vehicle anyway because we needed a little more tow capacity in addition to our mileage pushing 200K.

Sorry I could not help more.

[TiGG]

Resurrecting this one. I have the exact same issue as well. 03, v8 4wd 200k miles. Anyone solve the issue?

[Brian R.]

Go through the checks we suggested above. You may have a different cause or he may have missed something.

[SleepyHead98]

Sounds like a slipping transmission. As long as your transmission is not one of those specialty transmissions like Toyotas and Use world standard fluid, you should put Lucas transmission stop slip in it. Worth its weight in gold BTW.

In my car, 98 olds cutlass, It is notorious for having the second "piston" stick--so the second gear would shudder when going from first to second. I dont know if that is what your problem is, but this was a severe shudder, unlike anything else I have experienced. I put lucas in it 100k miles ago, and ithasnt slipped yet. Of course I did change the fluid twice in 100k miles. duh. Worth a shot.

[DGMAX99]

I actually think my original issue was something to do with the shift point modulator, or whatever controlled the shift points. I found the condition would only occur when I lightly feathered the throttle when bringing the vehicle up to speed, in other words, diving like my wife and accelerating very slowly. If I drove in a manner that was “normal” for me, it did not occur. It was like if I pampered it during acceleration, it would shift up no matter what the RPMs were, and in turn shifting into a higher ratio too high for the RPMs.

After challenging Toyota to resolve another issue I had with the check engine light being on for an extended period and my traction stuff being automatically disabled as a result of it (there was a TSB for replacement of the ECU for a limited timeframe that I was never informed of until it was closed) and them refusing to do anything about it...

.... I solved the problem... Traded it for a Nissan Armada...