2020 Tacoma driveline vibration

Bad batch from the supplier. They’ve made 20 million since they made yours.

 

not true, plus you need to show evidence they have changed the supplier just cant say its so and it is

 

Bad batch from the same supplier. You touched in the head or something? There’s 100 ways to get a bad batch. Bad steel, equipment out of calibration. Worn tooling. Shall I continue?

 

http://www.iron-foundry.com/brake-drum.html

 

I guess they had an unverified bad batch of drums for the 1st gen truck too, look same part # as 2nd and 3rd gen trucks, seems like only 3rd gens are warping out at 500-5000km miles
https://parts.conicellitoyotaofspri...RA-CAB-34L-V6-4x4-AT/63029039/4243104061.html

 

My 2001 tundra had a tsb to replace the rear drums. While i didn't notice them pulsing when applying the brake they changed them them anyways plus installed new shoe adjuster stars, and a serpentine belt at 14k miles.

 

welp, they changed the drums & the vibe stopped.

 

show us the work order, you wont cause there isn't one

 

MAKE ME

 

https://www.youtube.com/watch?v=4trn2lJxl00

 

Same for my 2020, it had pretty bad vibes when braking. The dealer replaced my rear drums at 3000 miles and its been perfect since. Im at 27K miles now.

 

My truck has this issue, it almost feels like there are some parts rotating that’s not 100% aligned. I few other from about 25-15mph.

Is that the “rumble strip” y’all are mentioning?

 

Mine didn’t happen when decelerating. Mine happened between 70-78mph. Went back to factory size tires and it’s gone now. I suspect the bigger tires changed the pinion angle just enough to cause a vibe.

Love the STFB. I have a few. Gold is okay, original is an amazing go-to.

 

what were the correct angles?
I have a 6 inch lift bds Fox dsc coilovers and old man emu coils in the rear with a 3 degree shim. Im experiencing vibes and I don't know what else to try.
I tried swapping tires and rims, spidertrax wheel spacers.
don't want to buy new tires to diagnose this.
I need help.

 

Ive been dealing with my vibes too and its driving me crazy, last 2.5 months nothing but bad vibes - no pun intended.

 

U mentioned decelerating..............

is that coasting down

or using brakes

 

My 2020 Pro MT just started doing this and it led me to this thread. Stick with me and I'll give my take on whats going on...

This is all driveline related and has nothing to do with the drums. The generically soft rear springs and the high gear ratios in these trucks is causing axle wrap (as mentioned above in this thread). By design, what helps these trucks move better is adding high gear ratio, but at the opposite side of the coin, on deceleration causes huge drag and mechanical friction during coasting. It takes a lot of effort from the ring gear to turn the pinion gear and driveshaft, transmission internals, and the engine against compression. (more noticeable in a manual trans because there is no slipping through the torque converter)

The ring gear is attached to the wheels. When you step on the gas, the pinion gear wants to climb up the teeth of the ring gear. The higher the ratio, (ex 4:30 4:88 5:29) the easier it is to do this... when this happens, because all the force is contained in a solid housing, it tries to spin the whole rear end inside the truck, and that is what makes the front of the truck "lift" when you step on the gas. the only thing that's keeping the diff from spinning is the U bolts that hold it in place to the leaf springs... Now, the same thing is happening when you take your foot off the gas, and coast, the ring gear is now trying to push down on the pinion, which makes the nose of the diff drop towards the road. it might only be able to move or flex the rear leafs so much, but be certain its changing the pinion angle enough that its causing some overbinding of the rear universal joint.

Pinion angle also changes when the truck has weight in the bed, and the axle basically lifts up deeper into the chassis (which will help the over bound rear U joint) and this is why when you carry a load you won't feel it as much. On the other end, when you apply the brakes, or lift the truck, you are raising the back end, (extending the diff out of the chassis) and making the pinion angle worse, and aggravating that rear U joint. Remember these trucks nose dive quite a bit when braking, which causes the rear to come up.

It only takes a few degrees to make quite a difference felt in the drive shaft angle, and by design, with the fixed position of the hanger bearing to support the 2 piece drive shaft, the distance is quite a bit shorter at which the driveshaft angle calculates from, because the hanger bearing doesn't move in the chassis.

The only ways to fix this is either change to a single piece driveshaft (reduces the ground clearance of the shaft), replace the driveshaft with a double cardan joint (uses 2 u joints to split the angle for each U joint in half), change the leaf springs with a different perch angle, or, a more rigid leaf pack to reduce the amount of wrap, shim the axle perch with an angle shim, or shim the hanger bearing down to better align the driveshaft angle with the pinion...

 

My 2020 shakes too!
Had the drums replaced dealer said they were warped first time they had seen it.
Put a set of rims with snows and different vibe now at highway speed, just put factory wheels on and going to test again before truck goes in on Saturday.
It’s like no other vibe I’ve experienced sometimes under braking but constant shake over 50.