My truck has been making a grinding noise for a while now (about a month). I have taken it to 2 shops and a dealer and its still not fixed, but we are narrowing in. Looking for some extra insight. Let me list the characteristics.

- Only on power
- Present across the RPM and Speed bands, but more distinct 25-40, likely due to engine noise covering it up, and tire noise at speeds above 55mpg.
- Not always present, even on power
- When it does bare its teeth, it seems to always follow a transmission shift
- You can almost "cause" it by shifting into a gear, easily, then just lightly accelerating.
- It can be felt lightly in the floor/pedal.
- Sounds like a roar, grind, or rumble. Sounds always stays the same.

Its been to 2 transmission shops, one said they couldnt hear it, one said it sounded like a bearing, and a dealer kept if for 3 days and said it might be the flex plate. This actually makes sense, as once I took off the inspection plate, and a god awful noise emanated from the flex plate area, but my untrained eyes saw no obvious damage.

Now, before you bash me for going to Ford, I went to a local trans shop, AAMCO, and then Ford. Ford was cool, they kept it for 3 days, and charged me with nothing. I asked them for an update today when I went to pick it up to get to work this weekend and they told me the diesel guy and trans guy are going to sit down and talk about it/look at it, because they dont want to throw parts at it guessing, and want to get it right. I was impressed by that.

Any input from you guys?

 

How's your carrier look?

Pop

 

I'm clueless in that black box between drivelines and the engine, but I am fully versed in frustrating symptoms. I'm here with pom-poms in place of a wrench.


My flexplate did not have a noise when I pulled the inspection plate, for comparison.

 

What would I be looking for. When I grab the drove shaft I can move it to and fro just a bit, sounds like a rubber bushing moving around.

 

The stock rubber bushing surrounding the carrier allows for a bit of "play", the aftermarket urethane ones do not.

Maybe time to hook up a GoPro under there to see what's going on.

Just a thought..........

Pop

 

Can you duplicate (re-create) the noise when the truck is stopped either in neutral or in gear at a stop light? What happens if you powerbrake the truck in gear with the brake pedal mashed and not allowing the truck to creep or move?

We are starting to see these Flexplates cracking and the cracks can't be seen until the trans comes out as they are cracking in the center where they bolt to the crank.

However, Torque Converters can make noise too regardless of mileage, etc.

 

I am not hearing the same noise when idling in park, or while power braking. Although I'm at work and not keen to power braking in the parking lot for very long so I'll try it again at home later. However I passed through the typical rpm range it occurs, stopping at 2k rpm

 

I have identified that it ONLY occurs in gears 3 and 4.

Shifts remain firm and smooth, with no signs of what I would identify as slipping.

 

I'd look at your torque converter slip with AE - it locks only in 3rd and 4th gear. Even if there's no slip, it can tell you if the noise coincides with TCLU.

 

Good idea Rich. I forgot that that is a reported PID. No AE but Torque tacked the job.

I took the truck out of the tune and into stock for logging.

I learned a few things.
- Going back to stock changed shift points and revealed new facts

- In stock, the noise appears in 2nd gear as well

- Watching the TC Slip graph and digital gear indicator allows me to feel when the TC locks up, and know what gear I'm in also. This revealed that the noise does not seem to corelate to TCLU

 

Ah... progress. I wonder if it could it be transmission fluid temperature or pressure related.

 

TFT has been normal according to aftermarket gauge.

 

Trey, that sounds like exactly what my carrier bearing was doing. Had a couple u-joints going on their way out too, but right down to the speeds, your description matches what my symptoms were.

 

My carrier bearing seems okay, but I don't really know what to look for, I just kinda wiggled it.y u joints were replaced NY the PO and have been greased regularly, but I'll have the shop look at that too. Would there be excess play in the drive line if those were suspect?

 

I'm no expert, Trey. Honestly I couldn't really tell the difference in the carrier bearings from old to new beyond looks. All I know is changing it out fixed the issue. Only way I've ever been able to properly ID bad u-joints was to remove the shaft. With the shaft in place.... they looked fine. Pulling the shaft off...I could tell they were bad.

I did cheat and have my mechanic do them for me last go around. The damn nut was stripped on the carrier bearing and I didn't want to remove the tank to get to the damn nut, so I just had my mechanic cut it off and replace it.