Lately i have noticed that when I slow down but not stopped all the way then hit the accelarator to like pass or just to pick up speed, the truck slams into gear hard then goes. One time I thought I broke something it slammed so hard its more like the rear end slamming, but hard to say. Why would that be happening?

 

stupid question, but are you sure it's the tranny? mine felt like it would lunge every once in a while, i mean, when you would stop it felt like it had to catch up to you, and then when you took off it's like the rear end had to catch up. i took it to the dealer (when it was still in warranty), and they greased (i think they called it) the slip yoke?, but not sure. hadn't had any problems since then.

 

My truck did the same thing. I dropped the pan and changed the tranny filter. It was filled up with junk as well as the magnet. Added 5 qts and she shifts like new. This was at 65k. Now at 70k with no problems.

 

sometimes too i can get ahead of my trucks drive by wire system. there is no throttle cable in our trucks, just an electric current that operates a servo on the throttle body. if you give it a decent amount of throttle, sometimes it will lunge on me trying to catch up.

 

I had that problem about 8 months ago in my 2005 FX4, I thought it was the tranny but I took it to the dealer and they had to replace the driveshaft as there were metal shavings in the yoke. Luckily I had the extended warranty because it cost $1200.

 

My '04 did that when new. It did it mainly at lower speeds in the 1st-2nd gear range. It was very bad sometimes. Everyone that rode in my truck commented on the issue and asked me "whats wrong with your new truck"?

I took the truck back to the dealer 3 times to check it before the warranty ran out.
All three times they could not find anything wrong with it.

One day a crazy thing happened. I ended up fixing it myself by accident. I bought a Flashpaq tuner for the truck. When I loaded the performance tunes the tranny problems ended. I didn't buy it for that problem but got lucky.

I guess the more aggressive tranny settings in the tuner changed whatever bad shift habits that was tuned in it from the factory. I went as far as removing the performance tuner and reinstalling the factory tune. When I did that the problem reoccurred.

My findings? It was the tranny and it hasn't done it in nearly five years and 100k miles since I bought and added my tuner.

 

If it sounds like from rear the slip yoke is my first guess. Does it clunk from a stop? Then - do you have a tuner on it?

 

It does clunk from a stop, it just slams hard into gear each I try to slow down then take off again, it s kinda wierd. i will take a look at the slip yoke, it really seems like it is coming from the rear. Kinda good to hear from others having this same issue, hopefully I will fix it and once i do I will post results.

 

Check the U-joints. Mine was doing that and I changed out the rear one.

 

My sons Ranger did that, I went to dealer and got a tube of special slip yoke lube, Its teflon and its called PTFE. Drop the driveshaft after making position with chalk or crayon. Take clamps off rubber shroud that covers slip yoke. Degrease slip yoke, I used brake cleaner and old toothbrush. Let dry then apply the PTFE lube liberally. Put together the same way it came apart. I used nylon zip ties to attach rubber shroud. Put it back together being careful to align your marks and it should be as smooth as a baby's butt!

 

Might not have anything to do with your situation but mine did this REALLY bad when I'd slow down to 25mph. I cleaned the throttle body and it went away. I can't even feel it shift now. You could try it and if it doesn't help that problem it's a good thing to do.

 

my 2010 did that and they had to replace wires in the transmission. something about shift points also.

 

mine does it. i have to be real easy when i let of at cruising and get on it again or CLUNK! is it hard to grease the slip yoke? whats involved getting to it?

did mkinttrim explain what i need to do?

 

i still havent tried it yet, its so cold but i am going to try what mkintrim said.

 

Mine does the same thing. I have heard that in some cases it's the torque management in the computer. That why when you have it tuned and the torque management adjusted it fixes the problem. I will know if this is true in Jan when I get it tuned.