Jrunner01

I've had my 01 4runner for about 4 months now and everything was running great, until a few days ago. V6 3.4l and it has 125k miles on it. 3 days ago my transmission started really hitting hard when it shifts into o.d. And when it's in o.d. There is a very faint hissing or metal on metal noise i can hear coming through the vents. this happens when it's both hot and cold at any speed. It shifts fine into reverse and drive. It runs normal in o.d. But it's just the noise and the really hard shift problem. Once i click the o.d. Off it down shifts nicely and the noise is gone instantly and runs perfectly through every gear. The fluid level is normal but it is almost a brown color so i'm going to change it and the filter. How worried should i be that it's the trans going out? Thanks guys

97ltd4x4

Sounds like a possible torque converter lock-up clutch problem.I would do a trans flush.It might get better...I have no idea about the noises you are hearing through your vents though...

Jrunner01

i forgot to mention i had a mechanic friend look at the drive line about a month ago because i was getting a vibration underneath the floor when i hit about 60 on the freeway. it would only do it when i was barely stepping on the gas peddle. he lifted the truck and had me accelerate up to 70 and down again. he said there was definitely a vibration transferring through the drive line but he couldn't pin point if it was from trans or from rear end. i just talked to him on the phone and he said sounds like the trans is starting to go out, but i'm not 100% convinced. he said if i change the filter and fluid it will probably get worse. does it sound like the hard shift and vibration are related?

97ltd4x4

Usually if the fluid is really burnt and stinks and then you flush it with new fluid you might make it worse.If the trans slips and you flush the fluid very likely it will get worse...

If the torque converter lock-up clutch starts to chatter and you flush it...It might get better,because of the higher psi capacity of new fluid is now going to put more pressure on the lock-up clutch which might make it not chatter.

One thing to add.If it was mine and there was a posibility that the lock-up clutch was going bad...I would flush the trans,just for the simple fact that if the trans is shifting up and down normally..Its telling me that the clutch packs are ok,also the valve body is working properly....so I would want to get the old fluid with all those particles from a failing clutch out of the trans..so it dosen't cause a problem with the valve body..and then the clutch packs smoke....

One way to tell for sure is to pull the pin out of the ECM that controls the lock-up converter clutch..drive it and if all is normal...That's your problem and you are looking at a torque converter.....and all will be fixed..........If you let the fluid burn up to the point of shifting problems..You are going to need an entire trans....Big $$

Jrunner01

you don't happen to know the location of that pin do you? i'm not really familiar with the electronics aspect of cars and trucks lol. thanks for your help by the way