I know this was posted before, can't find it.
Once in blue moon, after sitting on red, or in stop and go traffic, when I let go off the brake pedal and try to accelerate, there is nothing happening, then with a loud bang and jerk, truck picks up and moves just like normal. It can do this once in 2 mths.
It feels like as if trannie locks into parking, while sitting at red light.
No error codes. Truck drives ok for 100K miles.

 

Mine does it when one of the back wheels looses traction. First time it happened felt and sounded like I was backing into a brick wall. Don't know if it is normal.

 

sounds likes its low on fluid

 

fluid is good. it does it only ever so often, more rarely than often. just like something locks trannie and lets go with a BANG!

 

Hello,

If the fluid level is good, then you have something sticking in the VB like the 1-2 shift valve, or maybe the pressure regulator valve in the pump. What ever it is, its a hydraulic or a mechanical issue. Not electrical. Basically when you come to a stop and it does this, the trans is going to a neutral state and when you rev it up to go it builds enough pressure to move or apply and bang, it hit hard into gear. Hope this helps.

 

that's exactly what it does! so, now that we know what to fix, how do we fix it? I am slowly replacing ATF with Royal Purple one, quart a month. what else? I'll try TransTune, except that you can't drive on it, and I can not remove the drain plug.

 

First, don't replace the tranny fluid one quart a month. How do you even do that? Change it once and change it all.

Second, use Lucas transmission fluid. The best stuff on the market.

 

very carefully. suck it out through the filler tube.

try removing drain plug or oil pan on my truck, then we'll talk about replacing it all at once.

 

LOL, the drain plugs on these trucks are about impossible to get out. They just round off most of the time, they really have no purpose.

 

A trans mechanic showed me how to remove the drain plug... Strike the plug a couple time with a hammer, and use a 6-point socket to reomove the drain plug. DO NOT use any type of powered tool (impact wrench) or it will round off (like mine did).

Success.