Rumble Strip Vibes

Hi everyone,

Have gone through the exhaustive posts addressing this issue but was looking for a little more clarity on this.

For reference, truck is a 2015 with 100k miles on it, 4x4 full cab long box automatic.

It has a 2" spacer lift installed currently that provides some other (tolerable) vibrations as i don't believe the previous owner installed the cb drop or diff drop - reducing the lift with new bilsteins to 1" rear , 2" front soon.

Anyways, after driving for an extend period of time, very infrequently, at about 1100 rpm (i have only felt this in 2/3 gear) and very light throttle, the truck has a rumble strip sensation until the revs are increased or i manually put the truck into 4 from Drive. I think applying the brakes also fixes the sensation.

Based on my reading, this is the torque converter locking up and justifying some type of repair.

Now, my question is i guess pretty straight forward. Do i need to replace the TC? Flush the trans and add lubeguard FM, or is it an actuator / pump within the trans?

I am certain the transmission is the source of this issue based on the aforementioned techniques to fix the issue when it arises.

Thanks in advance!

 

Can you describe the “rumble strip” sensation more?

Are you feeling it in the steering wheel? (Front of truck) or your seat? (Rear of truck).

how did you determine the transmission was the culprit?

 

The whole truck shakes like driving over a rumblestrip, i haven't noticed it through the wheel

Based on the symptoms, and compared to what i've read / what causes the issue the go away, i'm fairly confident it's the trans. For example 250 rpms more and it's no longer vibrating, or manually switching to 4th gear

Let's say i drive for 15 mins or so and an instance arises where i'm going along a flat / downhill road and i give the truck a touch of gas (rpms around 1k-1100) it instantly will shudder until i give it more gas or flip it to 4th (longest instance of shuddering has been about 3 seconds)

 

Do you notice if it happens at specific speeds? Many of the 2nd Gen trucks have driveline vibrations at specific speeds. Mine does it from like 35-45mph sometimes.

 

It sounds just like torque converter shutter. You have nothing to loose by draining the fluid and adding LubeGuard.

 

I replaced carrier bearings around 100k-ish miles on my gen 2. Might be worth looking at. Maybe check the driveshaft. Mine only did it in certain circumstances (speed/throttle/rpms) and that was the culprit. It was an easy fix.

 

sounds like a torque converter shudder issue. you can try to a transmission service and see if that helps the issue at all there are additives out there that are supposed to correct TC shudders that you can add. I had a vehicle that had a pretty bad shudder from the TC and after doing a service on the transmission it was much improved

 

Probably just going to replace this anyways but not confident it would be the cause.

For sure, might as well start with a full flush and lubeguard - shouldn't be too much

 

Last Time I had dealership do my transmission fluid was like $330.