Loud pop in transmission (i think)

[lewdog998]

General spec
2020 TRD pro with 33s, stock fox suspension with eibach springs...maybe 1/2 -1 inch taller than stock PRO. DK ucas. All suspension mods done over a year ago so i think that is not an issue. 60k miles

I have not exercised 4wd in several months. been busy.
I dont know if this has anything to with it...but timing is suspicious.
I exercise the 4wd about a week ago...worked fine.
A couple days later i hear a very distinct pop at low speed only when braking like coming into a parking space. Very slow braking there is no noise. But a quick jab will cause a pop that you feel in the break pedal. does it both in reverse and forward.

Parked it and went out of town for a week. Came back and the noise stopped. Went for a few days with no noise....

The noise came back ( i remember exercising the 4wd again, but cant remember if i did this before or after the noise came back). This seems to happen in 2WD Mostly.

Its a very distinct pop almost like a bad ball joint...
ALSO it happened when completely stopped and shifted from neutral to reverse.

Heres what i have done.
1. Checked the front end and greased all joints (no change)
2. Checked all joints front and rear driveline (no change)
3. Made sure front shaft was not engaged..spins freely in 2wd, yet still a pop. (no Change)
4. Removed full skids to make sure no interference (no change)
5. Trans fluid, cases and diffs all good level and changed at about 45k.

Have not made any mods to truck in over 6 months.

Have a dealer appointment tomorrow but wanted to be armed with ideas if anyone has any.

Any thoughts?

 

[02SE]

Have you checked the torque on all of the fasteners which were involved in the lift install?

There have been pics of broken Eibach springs here too, so check the coils closely.

 

[lewdog998]

Have you checked the torque on all of the fasteners which were involved in the lift install?

There have been pics of broken Eibach springs here too, so check the coils closely.

Checked all the fasteners...all good. I can stand on the frame sliders, grab the roof rack and rock the truck side to side as violently as possible...I weigh 220lbs and not get a single noise or creak.

i did not inspect the springs specifically. I will check those tonight.

 

[lewdog998]

Took it to the dealer...its still under warranty. They said they could not duplicate it, but that he has seen that issue before and that it is NORMAL to do this sometimes. Something about the gears getting out of sync sometimes. I inquired as to who checked it, and he said it was a "master tech" and he checked out everything..fluids etc...and mad NO recommendations which the rep said was a bit unusual.

It has never happened since new, and the only thing I can think is that 4wd has not been used much at all in the last year due to being so busy at work and driving my LC100 half the time. I will exercise the 4wd frequently in the ext few weeks and see if it clears up. I take a little comfort in knowing that we have now at least documented the issue at the dealer.

Have any of yall heard of this being normal?

 

[02SE]

I was a Master Tech at the Toyota dealer, and some independent shops back in the day. I built and rebuilt more than a few transmissions (mostly Fords). I have no idea what they are trying to say with "gears getting out of sync sometimes".

That sounds like a clueless service writer making up some BS explanation.

 

[NorthPark]

Can you duplicate the sound with the vehicle off?

Try to drive it over some speed bumps at different speeds and angles and see if you can hear it. Go slow but try to find different ways of actuating the suspension, do front and then rear as you go over them.

Get up on your sliders/steps if you have them, grab your roof rack and just rock it as hard as you can side to side

A notorious loud clunk is the rear upper control arm frame side after a lift. It's difficult to get up in there and torque those bolts properly. The few times I've ran into missing upper control arm bolts, the noise was heard while parking forward and reverse. The noise was not present with normal driving

Bushings can make a pop sound, but usually if it's a loud bat type of sound then a suspension component is loose

 

[lewdog998]

I was a Master Tech at the Toyota dealer, and some independent shops back in the day. I built and rebuilt more than a few transmissions (mostly Fords). I have no idea what they are trying to say with "gears getting out of sync sometimes".

That sounds like a clueless service writer making up some BS explanation.

That is exactly what I was thinking!
I can't see how thats possible....maybe there is a sticky actuator thats not fully disengaging.

 

[lewdog998]

Can you duplicate the sound with the vehicle off?

Try to drive it over some speed bumps at different speeds and angles and see if you can hear it. Go slow but try to find different ways of actuating the suspension, do front and then rear as you go over them.

Get up on your sliders/steps if you have them, grab your roof rack and just rock it as hard as you can side to side

A notorious loud clunk is the rear upper control arm frame side after a lift. It's difficult to get up in there and torque those bolts properly. The few times I've ran into missing upper control arm bolts, the noise was heard while parking forward and reverse. The noise was not present with normal driving

Bushings can make a pop sound, but usually if it's a loud bat type of sound then a suspension component is loose

Can't duplicate with off or neutral....I did try rocking it really hard...no noise.
I haven't heard it over speed bumps or driving speed when hitting bumps.

Just picked up and it has stopped. One of the serv "advisors" tried to rexplain the meshing bs again...but after I showed him the video and he heard it...he agreed that it was not normal.

It has stopped for now..but I am going to test it further to see if I can get it to come back.