I have a 99 pathfinder 2wd. What happens is after about 15 min. on the highway the vehicle shakes really bad. I pull over wait a minute or two and start down the highway again without a problem for about 10 to 15 min. It's not overheating, the tires are brand new with alignment, and it doesnt stop shaking until you pull over to a complete stop and wait and then proceed again. So I know it's not the high speed balance,becuse it does this at what ever speed you are at. I runs really well low speed or high(65 to 75 is what I drive on h-way) It will do that everytime after 10 to 15 min. on the highway. On regular streets there is no problems.

do you have also a feeling like your rear wants to wobble left and right ??

Hard to say because it seems like the whole damn vehicle wants to fall apart. But if I had to say yes or no I would say no. The source seems to be coming from the front

ok then... If it really takes 10-15 minutes before it starts, it could be your torque converter.

Try going on the highway while having your overdrive off. A yellow light on the dash should confirm you that the overdrive is off. see if it does it still.

If it does not, then you know the problem comes from there...then we can continue funneling it down further...

Thanx, I'll try that.My wife should be leaving work in 2 more hrs. I will tell her to disengage the OD. Cross my fingers,because not knowing is the worst. I'll keep you posted.

Well we drove it with the OD off and it still did the same thing as before. I even talked with a mechanic I know and he seems stumped. Any ideas ?

Now we know it's not your overdrive, but it can still be your torque converter lockup solenoid. What it does, is when the trans oil and engine coolant temperature are hot enough, it will send a signal to the tcm (transmission control module) to say to the TCC solenoid to activate. This will lock the transmission in gear . What you are experiencing , in my opinion, is called torque converter shudder.

This is to save gas and wear on the trans. Now confirm if i'm right, when this happens and you press on the gas (in order to force a downshift), the shudder will go away, right ? Then when you release the gas, it will start again..?

Also, it should not be doing it right after you start( because the oil and engine coolant are still cold, therefore not sending the signal)..

There is one easy thing that you can do to see if it is. It will require you or your mechanic to disconnect the TCC Solenoid valve connector. Unfortunately, this connector is under the transmission oil pan. So you will need to , drain the trans oil, remove the 10 or so bolts holding it, then disconect the tcc valve connector and re-assemble everything and put new oil.

It may seem hard , but really it is not.

download here the transmission repair manual for your pathy, that I have put here for you : http://www.4shared.com/file/242412000/e ... nline.html and look at the page AT-257 to get a look of what the TCC valve looks like.

When you are going to remove the trans cover, you will see two connectors, one for the TCC and the other for the oil temp sensor. Using AT-257, find and disconnect the TCC connector.

Put back the cover and oil and run like this for a day or 2 ... you'll know for sure after that. You see, the TCC receives the signal from the TCM and this thing receives signal from the vehicle speed sensor and throttle position sensor... Having the TCC disconnect will not change anything to your normal driving . It will only cost a tad more in gas... but it's for a day or 2 so , it should not be dramatic.

hang in there, we'll find it...

Wouldn't that trip a code and make the check engine light come on ?

The fact of disconnecting the tcc might trigger a p0746 i think which is TCC problem. but it will not make your trans go into limp mode.

It will either confirm the problem or rule it out... I have been reading alot also about probable cause of the tcc locking and unlocking right away and a few mention that a lack of oil might also be the issue. So that there is just enough oil in the trans to permit the lock of the tcc but not enough to sustain it...so it unlocks right away...

Check you trans oil level and make sure it is nice red...not black or brown...make sure it does not smell burned also....

S.

I'll do it. A mechanic I know thinks it might be the torque converter.He said to drop the trans pan, if I see small metal shavings its the torque converter.If I see big pieces its the planetary assembly. What do you think ?

I'm doing this with you so that you do not get riped off by a mechanic... Usually, if it were your torque converter and that there is a lot of metal shaving (or clutch plate material), your transmission would seems like it is slipping at every gear. If you floor it, do you feel power (torque), or do you feel it sluggish , like the engine is revving but the truck is just not pulling like it should ??

How much mileage is your 99 ?

A change of the torque converter is the last resort...

Like I said, check you oil level (Start the truck, wait until the idle is normal (low) about 5 minutes, and check the level while the truck is running.. There is a reading for the hot level.

Have a good look and smell at the oil. The symptom you have described to me seems to be a problem only when the lockup is trying to do it's job ... it does not seems like a full torque converter failure... There is a lot of stories like you that people had there trans rebuilt for good money only to see the problem come back a few months later....

Start with the easy first... disconnect the tcc it will take you about 1 hour to do and you'll see the result right away... Then I agree, if it still does it, then something is up.... If you read a bit the document i made available for you, you will see that the tcc valve has a small filter at the tip of it. It only needs to be small particle in there for the tcc to fail without it being faulty...s simple cleanup of it could fix it... You would be amazed how many people get themselves convince by a garage to change there transmision because it is so called <finished>, only to have the garage, rebuild it for a few dollars and re-sell it...

Believe me Im trying everything you tell me.You seem to know about these vehicles.I was only telling you what was told to me by others. I appreciate all of your help in this matter. I plan to drop the trans pan in the next day or two. I will disconnect the tcc and we'll go from there. Thanx again and I will keep you posted.

Step 8 of AT-240 shows you the connectors of the temp sensor and tcc.
You want to unplug the one that is going to the tcc that looks like this :

One more thing...when you disconnect the tcc, take 2 minutes to verify the resistance on it and the operation. Put a voltmeter to it following the procedure at the end of page AT-135. Also If you have access to a 12V battery, apply voltage to it by following procedure on at-136... if you can here it going on and off, then you just found your problem...

Good luck ... I'll be waiting for your report...

any news ?

What's up ??? Either you're dead or you won't bother giving a feed back..