I have a 2007 dodge ram 5.7 with 39,000miles. When engine and tranny are cold and I shift into reverse or drive there is a slight pause and jerk. Its nothing to bad or severe, yet anyway. I know the service on the tranny is not until 60k miles but you guys think that if I changed the trans fluid and filters it would help this. I am assuming that it is tranny because when the engine and tranny are warm it does not do it. I was thinking that if the trans fluid is a bit warn, it could lead to this. But there is a slight chance that a u-joint could be making it a bit worse ( I do realize that temperature does not have anything to do with the u-joints!!). That leads me to my next question, is there a specific time when you are suppose to change u-joints, or only when they fail.
thanks

 

i wouldnt see a problem in changing them out now .

 

i would say u joints for sure

i had a problem similiar to that on a occasion it would wat your describing when i shifted, but ussually when it was cold it would make a clicking noise sometimes a squeak but at first would only do it when it was cold or when i had a load. i replaced the u joints and problem solved

 

there is a TSB for the 05 and up rams, it deals with the spin on filter not flowing fluid well after it sits (truck is cold) and it hesitates with shifts. something to look into. ill see if i cant pull the info up on alldata for you real quick. but a fluid/filter change would def help if that were the problem. make sure your spin on filter part # doesnt end in AB

 

So I climbed under the truck to see if I could see any play in the u-joints only to find play in the rear end. When I twist the driveshaft the rear end rotates a bit. How much play is normal? I would guess it was 1/32 of a turn, not much but very noticeable.

 

If this only happens when the vehicle is cold and goes away when warm. I think the U-joints are ok. If you are not getting noise from the rearend then the play is also ok. I would check the rearend fluid level and or change it. And do a full trans service, changing filters and oil. Look at the removed oil for debris and see if that fixes your problem. Also there may not be any problem at all as the cold engine may well have an elevated idle causing the jerk when put into gear. Good luck..