When running in with the torque converter locked up, both in 3rd and in O/D, I will get a vibration through the driveline. This occurs in the 40 - 55 mph range, under light throttle when going up a hill. Once I back off the throttle slightly, the vibration will go away, but will come back when I start pushing on the accelerator again. The problem has popped up in the past few months. I'm pretty sure this is tranny and/or driveline related. I am going to get the tranny serviced soon. A friend of mine will be putting a shift kit in the truck, so I'll also be doing a new filter, synthetic fluids, and hopefully get the bands adjusted. So I was wondering if anyone had ideas on the problem and how to solve it, especially since we'll be getting inside the tranny at the time. Also, I know the transmission was rebuilt probably within the last 30K miles by the previous owner.

 

Possible early failure of a ujoint as that would be noticeable in the conditions you are describing!!!

 

Some Ford trucks and SUV suffered the same problem. Its's called torque converter flutter. It's due to the fact the the oil is starting to brake down and needs to be changed. Transmissions are servicable we need to change filters and fluid every 30,000. When your buddy dose the shift kit upgrade don't use regular trany fluid spend the money for the synthetic stuff you need to drain the converter as well. Remember don't mix the two that could gum up the valve body in the trany and you don't want that.

I have the 47Re Trany in my ram and I do run the Synthetic oil and have had no problems. I also Drive it like I stole it! So It's Abused like a truck should be.

 

http://dodgeram.info/tsb/1998/18-49-98.htm

also

http://www.babcox.com/editorial/us/us20040.htm

http://www.babcox.com/editorial/us/us50014.htm

 

If harder acceleration reduces the vibration at those speeds, perhaps the engine has a miss in it?
Is the ignition system in good working order? (You know,plugs,wires,cap,rotor, esp. timing)

Just a thought.

An engine misfire can be exagerated by the lockup function (no more fluid to dampen).

 

My friend runs his own tranny shop and just got a tranny flush machine. I think I'll go that route and invest in enough oil to flush and refill the who thing. I want to go with the ATF+4, that way the whole truck will have synthetics, expect the transfer case. Also, since I don't know what type of oil was put in when it was rebuilt, I am leery of just adding enough to top off.

My friend and Mojo have the same opinion on the torque converter being the cause of the problem. I may also be getting some slippage when it locks up, something I learned from another post I just put out. My friend seemed to think the shift kit will help out the flutter. He has a lot of years experience working on trannies, but I can't always follow him when he describes how everything works inside them.

HankL, I'll try to get to your posts tomorrow, right now the dial up connection is terribly slow. If the first link is about checking the gears in the differential, I've breezed through that once. I sure hope that isn't the problem. From what I remember, it recommends putting in new gears. OUCH$$$.

As far as the engine, I'm pretty sure that isn't the problem in my case. I've given it a tune-up within the last 4K-5K miles and it has always run smooth. That's a good tip to think about though.

 

I'm a mechanic, and would have to suggest getting under your truck and trying to wiggle your rear driveshaft up and down, if there is any play at all in it you have either a bad u-joint, or your rear pinion bearing is going out. Just my 2cents worth, good luck.

 

This quote is from the TSB HankL referenced. This describes my vehicle and the conditions. But I'm not sure about the torque converter part. For my truck, the vibration occurs only when the torque converter is locked. When the "torque converter engages", does this mean the torque converter is locked or unlocked? If it means the converter is unlocked, I can rule out the differential as being the problem.

I'll check on the u-joints also. That's a simple enough check that I should have done earlier. Thanks.

 

If you are going to a Dodge dealership to get a technician
to use that EVA 'black box' to zero in on the source of the vibration
my experience is that you only have a 50/50 chance
of finding a technician who has had the training to use it.

As we all know
there is a turnover of good technicians from one DCx dealership
to another, and to other automaker's dealerships as well.

It might pay to find your regional DCx customer service representative
and ask them which dealership has a technician with both training and experience on the EVA.

I will make another post in the forum with an old list of DCx representatives by USA region
but I am sure it is partly out of date.

 

When you engage the clutch, you let it out ... the torque converter is locked.