Wonder what the engineer means by “driveshaft hammering”? **. Corrected: (crankshaft hammering). TY

Could be different case with the new bell housing and same/similar internals. It was mentioned that first and second where changed/modified. Typically in a high torque situation programmers and developers can limit power output based on gear selection along with a host of other sensors feed back from throttle position, rpm, engine temps, load, etc.

Perhaps with the manual some of this wasn't implemented and the easy thing was to reduce power. or they lowered power until it didn't break. Just spit balling. I'd be surprised that such a small reduction would make that much of a difference. I also wouldn't be shocked to learn that there is a 7% variance in peak power output between different trucks coming off the line together once things get rolling. Mini Cooper had much larger discrepancies with their supercharged and turbocharged engines.

Lots of speculation at this point but it is entertaining, though not as much as it will be once we get these out on the road and have feedback coming in.

 

What R U smokin?

 

As an inhabitant of cluster b personality type, I need no artifice to amuse myself. Nor any validation. But, others are free to carry on!

 

Same question lol

 

The Moron holding the camera wasn't helping either lol. Pointing at random shit and distracting Andre when we needed him to process and question what just came out of the engineer's mouth. STFU Roman!

 

He said different bell-housing, accumulator deleted, and one other thing that I can't currently recall.

 

He also mentioned a different gearset.. hallelujah!!!

 

https://www.youtube.com/watch?v=Fh-s9O3EgRs&t=1040s

@30:00 Mr. Brown states its the "existing 6MT" aka RC62 @MOC221_ and yes! new gearset! I wonder if they kept the 4.30 rear end or if that was changed too. I bet 5th & 6th are still OD gears.

 

If only the "journalists" and influencers would think to ask questions like that eh?
Tundra went from 4.30s to 3.31? (don't quote me on that). I suspect the 4G Taco will have different axle ratios from 3G as well.
I would bet on 5 and 6 both being OD, but IMO those two ratios should be a bit more spread out (ie taller 6th). With gobs more torque at sub 2k RPM, it should be entirely doable.

 

Long time reader and Toyota fan boy. Thank you all so much for those answers. I read and learned something new from every reply. I’ve owned at least 3 Tacomas , 2 4Rs and now my 06 Land cruiser and really want to get into a new Gen 4 with a manual transmission. I appreciate the camaraderie of this group, as I try to narrow down my next mid size pick up truck. Thank you all again!

 

Engineers do not make things up. We deal with marketing and sales.

 

OK.

So, any educated theories on WTF crankshaft hammering actually is?

 

You ever let the clutch out wrong (too fast or to slow) with maybe a little too much skinny pedal? If you get it wrong the vehicle bucks and chatters.
Some cars get a flex coupling between transmission and driveshaft to damp that bucking. Taco does not, and even my 09 manual can buck depending on inputs. This could be the hammering he's referencing. If the power on tap is high, this bucking can be quite severe. I'm guessing shaving a few ponies you get under some threshold where that bucking could cause damage.
With the 8spd auto, you have a fluid coupling isolating the crank from driveline shock.

Just a thought

edit: based on the flywheel weight discussion Sheldon talked through, they must have been hitting a resonant frequency/mode at peak power. They could have solved it with a lighter flywheel, but at a drive-ability debit.

 

That is not a common term. Since the crankshaft is the part that takes linear force from the piston and converts it into rotary force for propulsion, my guess is, in some conditions like letting the gearing decelerate the vehicle, there was enough retardant force going back through the crank that was causing an adverse interaction between the crank and pistons.

 

The actual gear ratios have been released, even Reverse is better.

 

Oh?!!

 

Peak torque is raised to 2800rpms on the 6MT?

 

If it's anything like what I've been around it is just torsional vibrations. These come from fundamental characteristics in the power unit design as well as how the power unit is operated and controlled especially with respect to blending the two power sources. With a manual transmission the solid flywheel to clutch interface doesn't play as well with the vibrations ('hammering'?) as an auto with a torque converter.

 

Sounds like an easy fix aftermarket with a better flywheel and a chip. But anyone else concerned about the 1-2 ratio difference?