severe front-end vibration

[james kremer]

93 transport with 3800. my van is an se model with automatic trans.has 310,000 kms. when my van hits about 70 km hour,the front end starts to shake violently. my tires and wheels are fine. i dont have alot of money to spend on it, so if someone knows whats wrong and knows of a cheap fix, i would be very grateful. thanx.

[thadpole]

Even newer tires can have broken cords which are not visible by inspection. I had a tire with only 5000 miles on it. Without notice, it started to shake like crazy at a certain speed.
You should also check for play in the ball joints, tie rod ends, and rack and pinion. Do this by jacking up the car under the suspension arms, NOT under the frame, to keep the suspension compressed. See if the wheel has any loose play either side to side or up and down.
I assume you check the obvious, such as a chunk of mud or a rock stuck in the rim.

[GTP Dad]

It sounds like you may have a bad CV joint on the axle shaft. Does it smooth out when the speed increases to about 90KPH. If so I would believe that is where your problem lies.

[james kremer]

Originally Posted by GTP Dad

It sounds like you may have a bad CV joint on the axle shaft. Does it smooth out when the speed increases to about 90KPH. If so I would believe that is where your problem lies.

i don't know if it smooths out over 90 kph. the shake is so violent that i'm afraid of losing control, or the van falling apart.

[LMP]

I agree with GTPdad...just move under and try shaking the half shafts....one will probably exhibit much more slack than the other. These shafts complete with both cv joints are not very expensive as rebuilt and the mileage you have fully justifies this as the probably cause of such vibration. Damage to rubber bellows could let water in which would destroy the cv joint in a short time.