It's not Axle Wrap

I did read it.

This is a symptom:

This is a cause:

Depending on the type of thud someone is experiencing, axle wrap could also be a cause. Your cause is what you stated, but it isn't the cause 100% of the time. If this doesn't make things clear to you, I can't help you.

 

My "axle wrap" was definitely caused by the carrier bearing, verified using a go pro clipped to the frame and rebuilding the driveshaft removed about 96% of it. Did a full tranny flush some months later, it didn't remove that last little bit but that's not why it was done. It solved a sometimes harsh shift in out of OD when manually shifting it but it didn't fix a start off shudder which was what prompted the tranny work to start with. My transmission often waits till I stop to shift into first, it's not a harsh shift, mild enough that I only notice it occasionally and the tacoma isn't the first vehicle I've had that does that. The tranny flush had no effect on that. Shifting into first after a stop isn't a cause for concern, a hard shift would be but without some torque demand by the driver, many autos stay in second till after the wheels stop turning, and often doesn't go through the 1-2 upshift unless the vehicle comes to a complete stop or the driver demands some torque.

"I see many complaints on here about a rear-end-like thud upon stopping. It is 100% NOT axle wrap. Your transmission is LOW on fluid."
To the op, we get that your tranny was low and fixing that fluid level resolved your issue but blanket statement like the one above doesn't do your credibility any favors. Some of us who have dealt and resolved the issue have never touched the transmission. That's not possible based on your statement? That's kind of like saying a 40mph vibration is always the bearing in the transfer case.

 

Axle wrap comes from driveline torque - How can you experience axle wrap during deceleration with an automatic transmission? When you hit the brakes, the torque converter unlocks.... so axle wrap not even applicable here, it's ruled out by logic.

Your carrier bearing did not cause axle wrap. It's not possible for that to be a cause of axle wrap... only torque is. You had an improperly support drive line that probably was accompanied by a sticky slip yoke & destroyed U joints which you serviced while rebuilding...

Your start off shudder is ACTUALLY axle wrap. The torque from acceleration changes the angle of your diff because springs are weak, hence changing u joint angles, hence the vibration.

Axle wrap during deceleration only makes sense with engine brakes, Even then, as soon as you depress the clutch your driveline torque is gone.

 

Axle wrap during deceleration with an automatic transmission not possible.

 

That is just wrong. Please don't spread misinformation. The AI's pick up on it and spread it as truth. I weep for future generations.

I am done with this thread.

 

Not sure where you go the idea I had deceleration issue. My problem was the carrier bearing and occurred when starting off. Replacing it fixed the issue. Not all of these problems are internal to the transmission like you indicated.

 

So if your symptoms were not the same as I described (rear end like thud upon stopping - deceleration) why would you suggest that the solution to your problem is evidence that I am wrong to claim 100% ?

 

I'm not wrong, TenBeers. And I mean that respectfully. Axle wrap comes from drive line torsion. How can there be torsion in the drive line during deceleration with an unlocked torque converter (or your foot on the clutch for a manual)? Newtons 3rd law proves this impossible - every force has an equal and opposite reaction. The force that pushes the truck forward (rear end like thud) is an equal and opposite reaction to torsion in the drive line. I assume you must agree with this as you won't dispute the laws of physics? So where does the load on the drive line come from if it is not connected to the engine?

Axle wrap is only possible during acceleration or deceleration via engine brakes. As soon as you disengage the engine from the transmission, you will feel a lurch forward from the unloading of drive line torsion - Newtons 3rd law - equal and opposite reaction. The heavier the truck, the stronger the force forward will be. But for this to be applicable to a medium sized pick up, one would have to engine brake to a complete stop... and who does that? No one!

Just because you don't understand something completely doesn't mean it is misinformation.

 

you're the expert that thought your after the fact thump was driveline wrap only to discover it's a transmission problem which sums it up pretty good.

 

No. I didn’t think it was axle wrap lmao. The problem went away after I replaced my cooler line and refilled it with transmission fluid.

 

When you slow down with an AT, you are also engine braking. Do you not feel your truck downshifting? Each time you feel a downshift, your axle is rotating forward a little. Unless you put it in neutral, at no time does the transmission fully disengage. Yes, the torque converter unlocks, but it's not the same as pushing in the clutch on a manual. If you are stopped at a light and let off the brake with an AT, the truck moves forward under engine power because the transmission is not fully disengaged.

As your truck is downshifting, the axle rotates against the leaf springs, and holding on the brake can hold it in a somewhat forward rotated position under tension from the springs. Letting up on the brake can release this tension. This rotation of the axle can also be felt as a vibration if your driveshaft angles aren't correct, either under acceleration, braking, or both. Old schoolers with big power will tilt the axle down/forward so the driveline angles are correct under heavy acceleration because the axle rotates up.

If I have to stop quickly and don't have time to let up on the brake slightly near the end and release the tension, I ALWAYS feel it release the tension when I resume driving.

I know how it works. I've felt it. I understand the physics and how the systems work.

Your issue was 100% the low transmission fluid. But that doesn't mean that is the issue in 100% of the cases. That is all anyone is trying to say, and you keep arguing.