I have a 99 Ram 1500 5.2L 4x4 and when I hit around 45-52mph the 4x4 shifter vibrates extremely loud. Only does this when I'm on the gas accelerating and I've bungie it down to keep it quiet for now. Any suggestions on the root cause and potential fix? I've been underneath the truck poking and prodding and the the mounting brackets are secure but when I grab the transfer linkage tab from under the truck to the shifter, it wobbles a bit. I appreciate any comments or recommendations.

 

How many miles on the vehicle?

Something could be toasted inside the 'case itself but I'd first suspect rear u-joints or even rear end issues like pinion bearings.

Next I would definitely look at motor mounts. I service a '99 where the complaint was once that the shifter moved under acceleration, and indeed you could see it go left/right. The motor mounts were shot and it only had ~130k at the time. Just a 1500 with the 360.

OR, sometimes harmonics are fickle and nothing is wrong except slop in your shifter. I used to own an '02 Silverado and cured an annoying t-case shifter rattle with a generic rubber washer from the hardware store slid onto a pivot.

Still, the fact that you say you get it only under acceleration makes me think something more is going on.

 

The truck has 320k on it and I'm not getting jolting or vibration in steering wheel under heavy acceleration or hard braking. I'll definitely check the U-joints the first chance I get which I was starting to suspect. I do have a little little bit of play with the tab coming out of the bottom of the transfer shifter and wondered if my problem was with the linkage its self. Although you can see the shifter vibrating vigorously under acceleration/sustained speed of 45-52mph and it doesn't do this before or after these speeds. I do appreciate your insight and any further information you could provide given any more details I can provide.

 

It could be the transfer case linkage bushings. If you're getting a wobble out of those when touching/moving them manually, I'd seriously consider replacing them.

 

The steering wheel doesn't have much to do with your complaint other than to prove that your front tires are likely balanced and your front rotors are likely not warped.

You may be dealing with a power train issue, which is engine at the front sitting on two motor mounts, then transmission behind that which balances the motor with a single mount at the back (thus three point mounting: 2 motor mounts and one transmission mount), then the t-case hangs behind all that.

The power train could move considerably and you'd never know it through the steering wheel or brake pedal. On some cars with tight clearance the motor will eventually hit the steering shaft in the engine bay if it moves, but that's not really applicable to 2nd Gen Rams

KISS so the suggestion of shifter bushings is a good one. And checking u-joints is free save for 5 minutes of your time. You can also check motor mounts first visually and then have a trusted friend power brake while you watch from the side and toes clear of tires

 

Roger that, I appreciate the advice and points of concern to look for my problem. This is a bit unrelated but you fellas seem very knowledgeable and I've been doing my research so hear me out on this one. My engine temperature on my cluster always stays about 1/8 of the way away from median temperature and I'm thinking it's either the thermostat or engine temperature sensor because all my fluids are fresh and the engine appears to be operating within normal parameters. I'm going to get one of those blue tooth OBD2 sensors that give me the full run down to help better diagnose issues going forward. Thoughts?

 

Don't go looking for problems. If it's not overheating and the heater puts out adequate heat in the winter leave well enough alone. +/- 1/8 from vertical is nothing to worry about.

That said, investing in a basic reader that can give you live data is NEVER a bad idea!!