Torque converter?

[gtyates]

I have a 2005 Sport Trac with 131k miles on it. It has been maintained very well, including transmission service every 50k. The truck has a Class III receiver as well as an external transmission cooler, but honestly it has not pulled much of anything during its life. Over the past few weeks I am noting an odd knocking noise when the truck is going into or coming out of overdrive. I notice it under light acceleration. I can hear the noise, but I do not feel any difference, no shudder, and nothing noticeable on the tach. I have scanned the system using Forscan and no codes are stored. Is this the beginnings of the torque converter failing? Transmission fluid looks great, pinkish/red, no burnt smell, and no particles noticeable when I pull the dipstick.

Any thoughts appreciated.

 

[sr139fox]

My transmission went out. No notice, pink fluid. Lost reverse and 1st. The overdrive shafts and everything on it was fused together. $2,000 for rebuild.

 

[gtyates]

A little more info. I ran another Forscan scan last night. The only trouble code I had was for the Oil Sendiing Unit, which the Forscan notes indicated is probably a false reading. It was not setting a CEL. I cleared the code. Next I set up the Forscan dashboard and let it measure a few things while driving. I had it measure transmission temp, and a couple of torque converter related items. I let it create a file and saved it at end of my drive. The only thing that I fully understand in my reading s is the transmission temp, which was hovering right around 150 degrees, with fluctuations of around 4 degrees either side of 150. So temp is good from everything I can find on this transmission. I also had it read a torque converter percentage level and another torque converter related number. Those readings mean nothing to me. I understand computers, not auto mechanics.. If anyone might be able to understand the readings I saw I will gladly send you the file.

This morning on my drive into work I rode in silence and listened for the knocking sound. There were plenty of opportunities for the converter to lock and unlock as travel speeds were in the 40-45 mph range most of the drive. I did not hear the knock sound one single time this morning. The transmission was definitely locking and unlocking as I could not only feel a difference but I could see the rpm's change on the tach as well.

 

[gtyates]

Well, I spoke too soon. Noise is back. I am finding that if I turn overdrive off there is no noise. Is this confirming torque converter is gong bad??

 

[imp]

Well, I spoke too soon. Noise is back. I am finding that if I turn overdrive off there is no noise. Is this confirming torque converter is gong bad??

@gtyates

No. imp

 

[BrooklynBay]

Are the shift points smooth or do you feel a sudden jerk every time it goes into a different gear? Have you tested the 4WD system? Do you hear a clicking noise while making a turn?

 

[gtyates]

Are the shift points smooth or do you feel a sudden jerk every time it goes into a different gear? Have you tested the 4WD system? Do you hear a clicking noise while making a turn?

It is 2 wheel drive vehicle. Shifts are actually smooth. There is the typical 2-3 flair, but it has done this since i bought the truck in 2010 with 50k miles and has not gotten any worse. This O/D knock noise is new. As a temporary measure I have put some Dr. Tranny Fix in it, the 2 ounce bottle. I know this is not a fix, but curious if this will temporarily quiet it down. To me it so odd that I only hear this when O/D is kicking in or out. So far I have not noticed a loss in fuel mileage and no other issues, just the noise.

 

[gtyates]

An update. I put the Dr. Tranny Shudder Fix in on Sunday. This is Tuesday evening. I have had about 8 drive cycles for around 100 miles total driving since Tuesday. So far the 2-3 shift flair is gone. Woohoo! An unexpected bonus! The torque converter knock is still happening on occasion, but it is not happening every time it locks like it was before and is happening less frequently every day. There is a hill near my house where I was hearing it knock ever time after I crested the hill and was headed down the other side of it. Today I did not hear a knock either time I drove that section of road as an example. What is this telling me? Probably the torque convertor is on the way out. Time will tell.. Transmission fluid still looks great and has no odd odors. It was serviced @ 100k and I now have 131k miles. Given that the fluid still looks great and has no burnt smell I am leaning towards this being mechanical in nature. Will update more later.