2011 Auto Transmission shifting funny.

2011 TRD Sport. I've searched the forums and haven't seen anything that looks the same as my issue. I've noticed that when coming to a stop and sitting there briefly, the transmission seems to shift pretty hard into first. Possibly already in first and the transmission is just relieving pressure somewhere? The first time I noticed it, it wasn't very hard but I almost thought the person behind me had bumped into me lightly. It happens now and then, sometimes harder than others. Maybe it's normal? I've drained and filled the tranny once but it still does the exact same thing.

 

My 2006 does it too. Always has. I think it might be normal.

 

Your slip yoke may be dry.

 

Mine did this. Changed tranny fluid and it stopped. Not sure if it fixed it or if it's just coincidence but it's gone now.

 

I just had my tranny fluid changed yesterday. I will keep an eye on it and report back to see if it's still doing it.

 

Never would have thought of that.. But, it kinda of makes sense. Did you experience this?

 

Yes, braking to a stop rotates the rear axle forward extending the slip yoke, if the slip yoke is binding the energy is stored in the leaf springs at rest. When you accelerate the bind releases causing the bump sensation. Our 2nd gens do not come with a grease fitting on the yoke. You have to disconnect the shaft at the differential pinion, slide it apart, apply grease to the splines (clean up if dirty) the splines can only be re assembled one way but marking before disassembly helps take the guesswork out. Torque to spec, re-clamp boot. Mine started binding at around 70k Miles.

I still get surges from the ac compressor engaging at lights or stops but that's a totally different thing.

 

Yup...slip yoke binding caused by axle wrap. New better than stock rear springs will help.

 

That clears everything up! Thanks man. Totally makes sense. I haven't crawled under to look but can you re-use the clamp for the boot?

 

Best to get a new clamp although I have heard of people carefully relaxing the crimp on these clamps and re-crimping. I'm under my truck every 5k right now I just got a fat zip tie on It Worm gear type clamps may or may not cause vibration.

 

Zip tie works fine.

 

Thanks guys! I did the fix and haven't felt it again yet!

 

Old thread, but I finally got around to taking off the slip yoke and re-greasing it. What a difference. I used the Ford PTFE lube recommended by 'gearcruncher' on TW.
The factory "lifetime" lube was just about gone. After a clean up and re-lube, the truck is born again smooth going down the road.