Interesting trans issue.

This is for a RWD 2005 V6.

Been getting a shudder on light acceleration near 40mph when the engine is at operating temperature. Doesn't do it when cold. Turning overdrive off stops the shudder immediately. So I figured, bad torque converter. Brought it to a trans shop (local, great reviews, not a chain) so they could hook a scanner up to it.

The transmission never reached operating temperature, so the computer never sent a lockup command. Yet it still shuddered even though the torque converter should be uncoupled.

He wants to do further testing on it after the weather warms up - it's in the 30's here - and it's easier to get the trans up to temperature, but did notice that one of the 2 trans temp sensors was swinging 20-30 degrees any time he drove it around a corner. He put some friction modifier in the fluid for me to drive around and see if the shuddering goes away or at least gets better, and will have me bring it back when the weather is warmer.

This might be relevant - I have the common problem of OD switching itself on and off sometimes. I looked for a bare wire in the steering column but couldn't find it, so it still does it occasionally. It's not doing it when it shudders, though, or at least the light isn't indicating anything.

This trans guy seems to know his stuff, but I figured I'd ask people with a lot of direct Tundra experience:

What might cause 4th/5th gear shuddering that feels exactly like a bad torque converter if the TC isn't locking up?

I've already decided the temp sensors are getting replaced, but meanwhile, could that cause the issue?

 

Not an expert but that screams "low fluid level" to me.

 

Yeah, that would be a good thing to suspect. But I just had new fluid put in at the dealership late last fall, didn't drive it all winter, and the trans guy confirmed the fluid is fresh and full. Should have mentioned that in the OP, sorry.

 

It may circle back to transmission but do tires have crazy wear, possibly alignment issue. Drive train, ujoints good, no missing shaft weights. Don’t see many torque issues come thru here

 

Tires are almost new, what wear there is is even. The U joints look good to me, and the dealership confirmed that when they did the fluid (I asked them to look). Missing shaft weights, now that I'm not sure of, but I would think if it had a vibration at 40 from an imbalance somewhere it wouldn't go away instantly when I turn OD off.

 

Not trying to seem critical of that shop but it might be worth double checking their work. I think your sealed transmission has to be at a specific temperature when you check the fluid level and you already mentioned that it's so cold there that you are having trouble getting it up to temp.

Was the transmission acting up before you had it serviced last fall?

 

Yes. Dealership "couldn't replicate it," but I saw the mechanic accelerating hard, which never causes the shudder. Unfortunately we were in the middle of COVID stuff so I couldn't ride with him and get him to do it right. I had the fluid replaced anyway because I had bought it relatively recently and didn't know what fluid the last owner was using.