Small clunk when releasing the brake in reverse

I get a small clunk after I release the brake when the truck is in reverse and just start to move the truck. Is this just the drive line, or the movement in the brake calipers and is it normal. I just notice it more in my garage in the mornings when backing out for work. I will have to try to get a recording of it to post here. As far as I can tell there is no movement in the drive shaft / u-joints or anywhere else I have looked. Thanks

Edit: I can only get it to do it the first time I go from park or reverse after sitting overnight.

Right at the 7 second mark.

https://www.youtube.com/shorts/q6YRm3akHOw

 

Is it repeatable besides that one time a day? Have someone stand by the truck when backing and see where it’s coming from. They should be able to tell if it’s a brake or the driveline.

 

Edit: It happens only the first time in reverse after it has been sitting for overnight.

 

Could be simply the parking pawl. Try putting your tunny in Park first which sets the pawl, then set the emergency brake, release the emergency brake, then go.... See if that works. Worth a shot.....

 

I dont follow, it happens when I go from park to reverse and let my foot off the brake and start to reverse.

 

Video added

 

The pawl is set when you put your truck in Park. The pawl prevents your truck from rolling forward or backwards when the emergency brake isn't engaged. It won't roll much. Maybe a couple inches, but you might get a clunk sound. That clunk sound just might be the slack. You always need to put it in Park first to set the pawl before setting the emergency brake to set the slack.

 

My Frontier just had the parking pawl replaced under recall. The OEM pawl apparently failed on some 2022 Frontiers. A safety issue. The pawl is ubiquitous on 1/2 ton trucks with automatic transmissions. Most folks don't know what a pawl is....

 

My transfer case had to be dropped to access the pawl assembly which is attached at the end of the transmission. Not a big deal. I didn't have to do it. Got a freebie Altima to drive around for a half day.

 

FYI...."Park" Pawls aren't used on 3/4 ton and up trucks with automatic transmissions. A pawl can't handle the stress load from the weight of the truck. A different mechanism is used.
@ColoradoTJ might expound on this further....

 

The proper way to park an auto tranny, per the car care nut is as follows:

Come to a complete stop and with your foot on the brake shift into neutral, set parking brake, take foot off brake and let the weight of the truck fall on the parking brake. Then put truck in park.

 

I don't believe so.

 

That's why I don't follow car care nut.

 

It could be your driveshaft (slip yoke) needs lubed.

As your rear axle moves up and down while driving, the driveshaft must move forwards and backwards a little bit (or rather, lengthen and shorten). The driveshaft is designed to slide on splines to accomplish this. Sometimes it gets a bit dry and makes a clunk, which is particularly notable when torque is applied or let off. You may also notice it if you get a small "thump" a few seconds after coming to a stop.

It won't hurt anything, but you can take the driveshaft out and grease the splines if you want it to go away (if this is your issue that is).

This also won't cause any play that is noticeable when looking. Its only something you'll be able to see when torque is applied.

 

I don't think my 2019 has any grease zikrs on the u-joints?

 

Sorry I meant greasing the slip yoke not the U joints. Had to google what its called.

Have someone else shift it into gear and then watch the slip yoke from the side of the truck when it makes the noise, you might see it move.

 

Thats how I park my truck. Not because I seen it on car care nut, just because thats actually how you're supposed to park a car. Anyone who drove stick knows this, just obviously with a stick that last sequence is put it in gear after it's resting on the brake.

 

Manual transmissions don't have a parking pawl. Learned to drive using a manual in 1965. The clunk can happen on an automatic transmission when releasing the park brake if the pawl wasn't set first. This is commonly known as "slack". Simply depends on how you want to set the Park brake sequence. There is no wrong way.

 

That's great! 30,000 lbs....dang

 

Alls I know is, if I park the truck like most normal people do by just slapping it in park right away, when I go to shift into gear to drive the next time, it's much harder to shift and there's a noticeable stress sound. With the proper park procedure, it shifts super easy and smooth and you can feel there's no unnecessary stress.

 

Agree, this is how I park with any kind of a slope in play.
It makes me cringe when people park on a hill and have to force the gear shifter out of park because the weight of the vehicle is fighting them.
Let the E-brake do the work.

 

I think mine is even harder than most with the column shifter.

 

Keep in mind that I'm only trying to explain a possible reason for the clunk sound that the OP is experiencing not proper parking etiquette. When the emergency/park brake is set first the weight of the truck is held by the brake assuming that the emergency/park brake is functioning properly. All fine and dandy. Park pawl is not bearing all the weight. All fine and dandy. But.....the pawl may not be completely set. So.......if not on a level surface and when the emergency/park brake is released the pawl will fully set and possibly clunk when all that weight is released...and make it possibly hard to shift out of park unless your foot is on the brake when the emergency/park brake is released.

 

Gotcha, 2.5 gen Tundras have the pawl? I haven't heard of it

 

Most if not all automatic transmissions have a pawl assembly. The pawl is engaged when you set the transmission into Park. This prevents your truck from rolling away if your emergency/park brake isn't set.

 

Interesting, parking on a hill my '17 feels like it rolls into the parking gear and is tough to free it with the weight of the truck on it (hard clunk).

 

Nice level garage where I pull in and put my foot on the brake and then put it into park.