Another 3rd Gen torque converter issue?

ok...so you have 58K...has the fluid ever been changed?

 

It has not, which is my fault, should’ve had it done sooner I’m sure.

I am doing drain and fill, as well as having the general 4x4 service done next week

 

well...its way overdue...i would do as you mentoned..drain and fill it 3 or 4 times...it needs it anyway so that will rule the trans out if it doesnt fix it

 

Way overdue according to what?

 

well..if you go by what toyota says it never need changing...

 

Observations after getting the truck back.

- Rpm’s do not jump (exhibited traditionally when TC slips)

- Driving okay, for the most part.

Going to change my spark plugs, do the drain and fill, and inspect my motor mounts.

 

Change the pcv valve, they are only a few bucks and may help.

 

Drive in S4 around town and S5 at freeway speeds. RPM will stay higher, it will be producing more power and not bog.

 

@disel_V1 Check out the torque curve for the 3.5 on this video (skip to 6:00). https://youtu.be/qC7R8aGgZOI
I think the issue is that Toyota has the shift points set for maximum mpg, and it lets the engine lug similar to having a manual in too high of gear.
Based on the torque map, these engines should probably not be loaded below 1500rpm ever.
My dad and I have identical trucks, manufactured the same month/year. Mine does it, his doesn't. Not sure what determines when/why one does it vs. another.
I did try to ShiftSensePro from the video, but I just wasn't a fan of the shift points.

What i find interesting about yours is that is started at 58kmi... Most that have complained about it had low miles.

 

Weird question, but could you describe the exact feeling you get, and when exactly you get it?

 

Never had S, but I’m about to give it a shot

 

It exactly how you described:

"When the shudder occurs, I feel it right under the driver and passenger seat, and towards the front of the truck. It’s almost as if.. the rpm’s are too low, and it’s bogging down. I would say it’s not as intense as riding over speed strips, as some has compared it to, but instead a subtle choke for power.
Anyway, this issue is consistent, occurring 100% of each time the truck is driven"

My truck is super predictable also.
Only does it in the 40-50ish mph range.
Truck must have shifted into a gear that puts rpm below approx 1500rpm. Don't feel anything until lightly pressing gas pedal. If I push harder it downshifts and is fine.

 

Appreciate you! Lifted or anything by chance?

 

No. 100% Stock.
I did have TSB done for driveline vibrations, and although it did help the low speed vibes, it didn't affect the shudder feeling

 

Excellent, and to clarify, you don’t get the traditional “speed strip” sound and feel, right?

 

No sound. No rpm bounce. Just the "bumpy road feeling". It's not so pronounced that the truck is physically shaking or anything like that. It's just enough to be annoying.
Its easiest to feel on newly paved smooth roads. If the road is in poor shape and bumpy, sometimes it's hard to differentiate from the road.
@MarlonB54 had a 2020 that did it, sold it for a 2022, and it ended up with the same problem...
Like I mentioned though, ours did it right away.

 

My 19 sport double cab with stock/winter 265/65r17, and summer 265/70R17 wheels, with two inch lift, "chugs, shudders" while driving by foot, in D, between 40-60 mph when going up slight grades (think small rolling hills, or rises in the roadway). it is like the truck is in too high of a gear and just starts bucking, like a motorcycle in too high of a gear, until you give it enough accelerator to get it to shift down, raising the rpms. using cruise, or driving in D4, or D5, I do not have these "chugging" issues. this is a shift logic issue, and having 2 over drive gears, contributes to this. in reality, the truck should never reach 5th gear below 50mph, and never reach 6th unless over 65 mph. this is where I believe "our" issue is. too much gear, too high of trans gear needed for the speed, and load requested by the accelerator. Ski

 

Okay, most recent update

- Trans fluid clean, not burnt
- Shudder I experience, again more like a bumpy road, is observed on flat as well as going downhill
- Rpm’s not jumping, or moving slightly up and down like you’d typically see with transmission specific related issues

TSB update made no difference.

Called the service manager directly, I’m going to take the foreman on a ride tomorrow and we are going to use a computer and flag each instance it occurs. Will also be checking for dead misses, and anything else spark / coil related. This was not done yet.

I am incredibly disappointed it’s this much of a struggle to get this properly diagnosed, but I also understand it. Everyone and their mother would be trying to get a new transmission every other week.

That being said, I have 59,008 miles on the ODO. The brake / gas peddle test clearly demonstrates that unlocking the TC stops the vibration / bumpy road / shudder feeling.

I wish the rpm’s also did the traditional dance they do when transmissions act up. Could also make pinpointing more specifics easier.

However, I’ve noticed within the last two days.. even putting it into gear, it feels like it slips. Rpm’s shoot up (1-1200). However, that’s only happened twice. Something similar has happened when I come to a stop.

Anyway, I know im over thinking everything at this point… but im going to give this one last try with the dealer. They claim they’ll take the readings from the computer and call Toyota corporate. Then they’ll decide what to do with said data in real time.

Optimistic, but not getting my hopes up. I know if I swap my TV (for nearly 2,000$) the issue will be fixed. However, I shouldn’t have to pay for something Toyota is clearly neglecting.

What annoys me the most is the “this is a normal characteristic of this transmission”. For 57.5k miles it surly wasn’t. I can accept the shitty shift mapping, but I’m not accepting a slipping transmission.

 

You can avoid the flex lockup shudder by driving around in S4 around town and shift to S5 at highway speeds. Or add a tube or two of Lubeguard to smooth out the flex lockup.

At low speeds the truck will shift to the highest gear for fuel efficiency and then pulse the torque converter lock on and off. I’ll bet a dollar that’s what you are feeling.

Get a full fluid exchange and add lubeguard. Toyota isn’t going to do anything.

 

the slipping is almost definitely the torque converter slip-lock. which is normal .