48RE Shutter/vibration from take off

[Maddey]

This last weekend I towed the tractor to the deer lease to do some work. I noticed that each time I took off from a dead stop, I would feel a shutter/vibration, kind of like the transmission slipping. I have towed this tractor (~10,000lbs) once before with no problems. The shutter/vibration would continue until I reached about 8-10mph. I also noticed this same thing happening the last time I towed the 5th wheel about a month ago, but it only happened once. I've never owned an automatic before, just 5 speeds, so I wasn't sure if this was something to worry about. I beginning to wonder if I have a problem. Has anyone else experienced this?

 

[Steve M]

I feel it every time I take off with our 10,400 lb 5th wheel. It's launch shudder. The rear axle twists just enough to cause too much drive shaft angle at the pinion. It can be shimmed to correct it under load but then you might feel it with light load. It won't hurt anything. I've thought about some sort of traction bars to stop the axle twist (spring wrap-up) but mostly I just ignore it.

 

[DJaquez]

I have noticed the shutter when taking off (empty) and the wheels are turned. I am thinking about a trip to the shop for documentation if nothing else.

 

[jcarver]

The shudder you are feeling is most likely your anti-spin differential. The new mechanical units they are using are very tight - this has been discussed in other posts. The first time mine did it I immediately thought it was the transmission. It continues to happen at 12K miles so I dont think it is something that gets better over time/miles. I dont worry about it anymore.

 

[Maddey]

Well... . I don't know if that makes me feel better or not. Hopefully this is just normal. Thanks for the replies. I got one more question. When I am driving empty or towing, my transmission shifts into overdrive at about 52mph no matter if I am accelerating hard or not. It seems to just shift from 3rd to 4th right after each other. Is there a way to change the shift points?

 

[jcarver]

Next time you drive your truck, count the shifts when driving from a dead stop. What you are describing sounds like the 4th to t/c lockup "shift". Mine will lock up the t/c as early as 42 mph on light throttle acceleration. You will know when the t/c is locked if you go to press on the accelerator and the rpm's dont shoot up like they do when it is unlocked. When counting the shifts you will see that it feels like the trans shifts 4 times. The 47RE is a 4 speed auto so it only has 3 actual shifts. 1-2, 2-3, and 3-4. The 4th "shift" is the t/c locking.