1988 Dodge Ram B250 Van Vibrates when I accelerate and stops when I let off the gas.

Any advice?

I guess I should add that this occurs in gear only.

 

Sounds like a misfire.

 

how about crawling underneath and pulling hard on the drive line where the universal joints are.. any play in them will cause a vibration when driving only, and not when just reving the engine. A van that old may have never had the u-joints lubed, and they may need replacing. You can also try jacking up the rear wheels securely, blocking the front tires, or getting it to a garage on a lift, where you can run the van in gear, spinning the rear wheels and looking and listening for the vibration source from underneath.

 

I had a '95 B250 van that also vibrated ( I will call it chattered) while at freeway speeds. Not bad vibration, but a similar sensation as driving on the rumble strips on a highway... just not as pronounced, in fact it was barely noticeable by passengers unless I pointed it out. The chatter went away when I left off the acelerator, but would come back as I stepped on the gas. My transmission man suggested a can of a No-Slip additive in the tranny, and after about 100 miles the vibration stopped completely and never came back.

 

This has to be done with the parking brake set, the wheels chocked, and the tranny in neutral. If the tranny is is park there is stress on the driveline which will prevent any free play from showing up.

 

About jacking up the rear end...I saw a tire shop guy jack it up from the differential, is this a good idea? I was wondering if this activity might have been the cause/start of the vibration.

 

I have always done it that way and it should not cause any problems. Given suspension travel, raising the truck by the differential is really the only way unless you own a set of high lift jacks that can do 26" or 28".