Does anyone get a double shift when your automatic goes into overdrive? Mine seems to have like a soft then a hard shift almost simultaniously. It might just be fourth and overdrive shifting at almost the same time. It does this sometimes not all the time. Is this something others have encounterd? Is this a normal thing?

 

Had the same question on my 04.5 48RE and was told that it was the converter lockup happening. Guess I still can feel 6 shifts on my 4 speed automatic so have be agree it is the lockup and overdrive combination causing the feeling.

 

Yep - mine too. Makes you think somethings wrong every time then you realize that its the same old thing that always happens once in a while. I seem to notice it more when the transmission hasn't warmed up yet.

 

Here is what you are feeling.
I will give the information as accurate as I can remember it from Dave Goerend.
The 3 to 4 shiftr happens in two stages. The area of the 4th gear clutch is too big for all the pressure to be applied at once. It would be very harsh and hard on the parts. So here is what happens. In the valve body, there is a passage that creates the 3/4 shift. It is divided and has a spring and ball. When the truck starts its shift into 4th, only half of the passage gets fluid. As the pressure in the passage rises, it pushed the spring, which pushes the ball, which opens the other side to let fluid in. So when the truck shifts into 4th, it is applying the fluid to do so in two stages and that is why it feels the way it does. Also, different throttle positions and rpms effect how much you can feel it because of the difference in pressure. It feels weird, but is how it is designed and is completely normal.

 

omaharam, thanks for the detailed answer, I have the same exact feeling while shifting, usually does happen when the truck is not warmed.
thanks again

floridagc

 

Thanks very much for the information. I feel much better now.

 

I have an 06 ctd with edge/Att, drive on L3, read the thread above heres my symtoms just started last week happend 2-3 times since under normal driving ,push gas down, downshifts, upshifts, rpms go thru the roof then catches moniter shows no slip at all ???????? have trans feature on to defuel for slippage

 

I have had 2 of these 48re tranny's in 2 diff. trucks. I have spent alot of miles trying to figure out how these things shift. The one thing that I have learned is there are not 2 of them that shift the same. I used to worry about the way they shifted. Not anymore. They do not shift the same 2 times in a row. I have figured out what rpm works the best and is the smoothist for my truck. It does take some time to figure it out. Once you figure it out, you will learn to love the 48re. It is a very good tranny.