I started to notice vibration coming from the front of my expy between 30-40 mph or when the engine is under load going up medium inclines. The harder I accelerate the more pronounced the vibration feels. When I accelerate slowly I don't feel anything. Once i get up to speed on the highway it runs perfectly normal and smooth. I have been reading alot of posts on the internet ranging from front drive shaft to the Torque converter to a bad coil on plug. Where should I start looking? Your help is greatly appreciated....
1999 Expy AWD Vibration on medium/hard acceleration
- Thread starter jcrisman
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
FordandPolaris
Full Access Members
Start with the free tests. Pull the 4WD fuse under the hood and try to produce the symptom. If no beans, probably front drivetrain related. Does it feel like it is more in the engine or the suspension? Can you feel it through the pedal, in your seat?
Does it feel like the engine is skipping beats/down on power? Just trying to narrow down exactly what kind of vibration we are looking at.
Does it feel like the engine is skipping beats/down on power? Just trying to narrow down exactly what kind of vibration we are looking at.
Last edited:
It doesn't seem to me like its the suspension. Yes I can feel the vibration through the pedal on acceleration. I will pull the 4wd fuse tomorrow morning and check for the vibration. If that fixes the problem should I focus on the drive shaft?
FordandPolaris
Full Access Members
Well it could be something with the AWD as well. If it is through the pedal, my guess is either vacuum leak on the motor or bad coil. I am guessing you don't have a check engine light on?
Like I said though, do the free test. Still pull the fuse and report back what you get.
I'm not getting a CEL. I failed to mention that I have a rough idle at stop lights.. I will check the hoses to see if I have a vacuum leak. I will also check to see if i have a bad ignition coil or boots. I had the plugs replaced 6k miles ago. I really appreciate your input, will keep you posted on what I find.
Hello All
Sorry for the delay in replying back. I pulled the 4wd Fuse, and the vibration has gone away. So i am guessing it has something to do with that. Where do i go from here? Do you have any recommendations on where to start looking? Thanks so much
Sorry for the delay in replying back. I pulled the 4wd Fuse, and the vibration has gone away. So i am guessing it has something to do with that. Where do i go from here? Do you have any recommendations on where to start looking? Thanks so much
FordandPolaris
Full Access Members
Try and wiggle your front driveshaft, do you have any play in the U-joints?
I got under my expy and I was able to twist the front drive shaft back and fourth. Forgive me for my ignorance, should it be able to rotate clockwise/counter clockwise with Expy not started? I shook it at the front U joint, no wobble or play in u joint. The rear drive shaft was rock solid, no twist at all or loose u joint.
so I found out that the vibration/grinding noise is the tranny. one of the clutches in the tranny has gone bad. the front driveshaft would not be the problem as there is no power to it on dry pavement because it is automatic 4 wheel drive not all wheel drive. getting a tranny rebuild soon. that might also be the reason why my truck wants to stall when I first start it up and put it in drive without warming up as the plates would be engaged until they warm up and broke loose but I am also going to check the vacuum elbow just in case
