Bet you can't answer this?

sant6236

sant6236

New member
Hi Everyone!

I wanted to promote a challenge in the sense I have just recently noticed a somewhat intermediate/periodic symptom on my 2001 T4R SR5.

The symptom:

Tachometer/RPM's go up and down in the range of 50-55 mph in Drive. It does not happen all the time, just sometimes, but have noticed it more and more.

This symptom is NOT experienced within the 20-35 range or the 60mph and over range.

Its as if the engine attempts to rev at this speed to go faster, but then drops off, in essnece switching back and forth and not being able to make its mind up. In turn, one can hear and see the tach/rpm's going up-then down rather quickly.

Keep in mind, these symptoms are experienced with a steady pedal or flow of gas when driving, making this puzzling.

In all reality, one would experience these symptoms if the exact opposite was occuring, that bieng pressign the gas and taking if off quickly, resulting in this tach/RPM switch back and forth.

Thanks for listening.
 
Register to hide this ad
Several questions:

Are you going over flat ground? Or are there slight inclines/drops in the road that would cause the truck to downshift/upshift from O-3?

Is the truck changing gears when this happens?

Have you messed with cruise control recently?
 
Yes, going over flat ground.

No inclines/drops in road.

I have not messed with cruise control lately, if you mean by tampering with the system. As for turnig it on and off and using cruise control. I rarely use it.

The truck I believe is in the process of changin gears when these symptoms occur and acts as if it cant make up its mind as to whether to upshift or remain where it was with regard to RPM.

MAke sense>?
 
"MAke sense>?"

It's not that I didn't understand your question, you simply did not include enough information in your initial post. The more info the better when you have problems. I'm no psychic, and neither is anyone else on this board... LOL.

Start with the simplest possible answer and go from there. Cruise control will make the truck shift in and out of over drive to maintain a specific speed - pertinent to the initial speed range you mentioned. Hence the question in my previous post.

Additional helpful questions:

What is the mileage on your vehicle?
When was the last time you changed your transmission fluid? When was the last time you checked the level of your trans fluid or the color for that matter? Check it in park while at idle. Could be due to low fluid pressure.
 
Most likely cause is the bad TPS (throttle position sensor)
 
Well it could be the Torque Converter. These autos have a lock up T/C, so once you hit O/D and are not working the truck too hard it will lock the T/C, basically making a direct connection between the motor and tranny, if it needs just a little more it will unlock the converter before downshifting to 3rd. This will be a small increase in RPM's, say a couple hundred. Going 50-55 you are in marginal O/D territory, so it may be unlocking the T/C more frequently than when you are travelling faster and running a higher RPM. When I first got my 02 and went to VT, I never owned an auto before, I thought the truck was downshifting for every hill and was disappointed, then I learned it was the T/C.

If it is the T/C you may want to hit O/D off in this situation, locking and unlocking the T/C too often leads to heating of the tranny fluid. If it is hunting between locked and unlocked or 4th and 3rd turining O/D off is the best thing to do.
 
My 2001 T4R has 114,000 miles on it.

I have recently changed the transmission fluid due to a ruptured transmission cooler line in the radiator.

Yes, it sent fluids both ways, but I have flushed and re-flushed the cooling system numerous times. coolant system is fine nor and hardly has any ATF in it anymorte.

As for the transmission flush it has been flushed professionally once and the color is TRUE red as it is supposed to be, instead of milk shake.

I am going to go check the fluid again to make sure though.

What kind of symptoms would a BAD TPS promote?
 
KellyJ said:
It sounds like you might be having a problem with your overdrive?
Click to expand...

Bingo!
Stepdad had the same problem and it got progressively worse, then he came to a hill and it ground away.

I believe I read somewhere that the 01&02 transmissions in the 4Runner have a weak OD planetary gear.
Stepdads went out at 124K.

did they mention anything about metal flakes the last time they changed the fluid?
 
The overdrive kicks in at about 48-50 MPH.

I have a little over 100,000 miles on my 4Runner does that mean that my O/D is going to be going out soon?
 
KellyJ said:
The overdrive kicks in at about 48-50 MPH.

I have a little over 100,000 miles on my 4Runner does that mean that my O/D is going to be going out soon?
Click to expand...

I can't tell you for sure.
Stepdads showed no sign till that weekend.
Its started off doing as stated above, then on the trip back it finally gave out.
So it can happen anytime.

When was the last time you had a fluid change or a flush done by the dealer?

IF you haven't gotten one check the fluid color, and if its till read get it changed and see if they find any metal fragments in it.
 
Well actually I just got a transmission fluid change and flush, as well as a differential change and flush. My mom did it for me before she drove it out here for me in about a few days. She said everything checked out well. Is shavings in the fluid one of the signs to O/D failure? My transmission still shifts almost as smoothly as it did when we first got it, so hopefully I won't have to deal with this in the car's lifetime. When the O/D goes out, does the car just not ever engage it? Do you just cruise at higher RPM's? Can you replace just the O/D gears? This info would probably be good to know for newer 3rd generation owners to know just in case.
 
KellyJ said:
Well actually I just got a transmission fluid change and flush, as well as a differential change and flush. My mom did it for me before she drove it out here for me in about a few days. She said everything checked out well. Is shavings in the fluid one of the signs to O/D failure? My transmission still shifts almost as smoothly as it did when we first got it, so hopefully I won't have to deal with this in the car's lifetime. When the O/D goes out, does the car just not ever engage it? Do you just cruise at higher RPM's? Can you replace just the O/D gears? This info would probably be good to know for newer 3rd generation owners to know just in case.
Click to expand...

Shavings in the tranny can be a sign of any transmission faliures to come in the future.

The car does not engage anymore.
And when you shift from park to drive it grinds through the gears.
Like I said step dad struggled to get it to the side.
The tow truck even had to tow the Runner by its rear (meaning the front tire where on the gound...)

So just keep a look out.
Toyota has never issues a Recall on it, but I have heard about it from other 01&02 owners.
 
So, what happens when one's OD planetary gear goes out.

What are one's alternatives or solution? New transmission?
 
Well I called John at IPT performance and told him everything I have been experiencing.

He said is sounds like a "lock up clutch in the torque converter."

He said my symptoms have nothing to do with the Od planetary gear and that if it was that, I would already be on the side of the road.
 
Well, I believe I have found the anser to my problem.

Here is the link

http://ezinearticles.com/?Torque-Converter-Lockup&id=113485



"If the TCC is bad one of three things will usually happen. First, the vehicle will tend to rev up and down as it engages and disengages, not being able to keep the converter clutch locked up. Second, the converter clutch will engage randomly in gears that it shouldn't even engage in usually. Third the clutch doesn't want to disengage. As you slow down the vehicle won't downshift and if you try to accelerate the RPM's will be so low that the vehicle will have difficulty moving quickly. In extreme cases the lockup converter will try to keep the vehicle moving as you try to stop at a stop light, or will stall out and die."
 
sant6236 said:
Well I called John at IPT performance and told him everything I have been experiencing.

He said is sounds like a "lock up clutch in the torque converter."

He said my symptoms have nothing to do with the Od planetary gear and that if it was that, I would already be on the side of the road.
Click to expand...

Well that's good news. Better then having to repair the entire tranny.
Stepdad made it about 300 miles after the first symptom started.
 
KellyJ said:
The overdrive kicks in at about 48-50 MPH.

I have a little over 100,000 miles on my 4Runner does that mean that my O/D is going to be going out soon?
Click to expand...

bump this...has anyone had any issues with their overdrive? My overdrive engages at about 50mph and 2000rpm, and shifts down to about 1500rpm, which feels too low when im driving (like if you were in too low of a gear with a stick, no power, etc). I used to get about 280 or so miles to the tank mixed driving, now I'm only pulling around 250-60. Thoughts?
 
sant6236 said:
My 2001 T4R has 114,000 miles on it.

I have recently changed the transmission fluid due to a ruptured transmission cooler line in the radiator.
Yes, it sent fluids both ways, but I have flushed and re-flushed the cooling system numerous times. coolant system is fine nor and hardly has any ATF in it anymorte.

As for the transmission flush it has been flushed professionally once and the color is TRUE red as it is supposed to be, instead of milk shake.

I am going to go check the fluid again to make sure though.

What kind of symptoms would a BAD TPS promote?
Click to expand...

In my opinion,
I'm going to say you hit the nail on the head here.
Sometimes you can go for a while after the pink milkshake, but it will catch up with you after a while.
I see a transmission in your future. Sorry.

I hope I am wrong.
 
You must log in or register to reply here.

Members online

Total: 252 (members: 1, guests: 251)

Forum statistics

Threads
278,309
Messages
3,554,071
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top