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This vibration has been in the van since I bought it. It starts just before 60mph and continues on up to around 75mph where if it is there it is very slight. By 80mph there is no vibration other then tires.. The vibration is fairly rapid and constant. It is hard to tell if it is from the rear or center of the van. Since I am the only one driving it, people sitting in the back, some say it is in the middle and others from the rear.
Other facts.
Starts just before 60mph wither in D or OD.
More prominent when pressing the accelerator and slightly less then coasting in gear.
At 65MPH and shifting to N, the vibration is still there.
Had a slightly bent left axle shaft and replaced it.
Had 3.55 gears and just rebuilt the differential with all new parts.
Had the drive shaft balanced and it was slightly out of balance.
New U-joints
Had Good Year tires and now have Michelin
Tires have been balanced and rotated several times Road Force balanced.
Front end alightment 3 times.
The rear spring bushings are old but not falling apart and do not have excessive slack.
Rear springs are within 1/2 to 3/4“ of factory ride height.
All new shocks and front end parts.
When the transmission is in OD, there is a clunk like slack in the differential when you rapidly give it the gas and let off back and forth. It did this before and after axle rebuild. In 1st, 2nd, and drive, it is very slight if any.
The transmission clunks quite often when shifting to OD and down shifting back to D at low speeds.
There is a slight wine at idle that comes from under the center of the van since I bought the van. I believe is probably the transmission front pump. It goes away around 800 to 900 rpms.
No vibration when revving the engine in park or neutral
Rpm’s at time of vibration are between 1800 and 2200 to 2300.
I have not checked the pinion angle to the transmission yet because everything is factory and I don’t really think the bushings are the problem. Perhaps they could be old and dried out and carry the vibration more then if they were new?
Transmission?
Torque converter?
Had the brake drums off when rebuilding the differential and they looked fine and came right off without binding.
Its not the torque converter because AOD's don't have a clutch in the torque converter.
My bet is its the drive shaft. Have a drive shaft shop check it for balance and that the joints are good. Also, the slip yoke can wear and cause this. So you might want them to replace the yoke while they have it. Its not expensive.
Thanks for the tips Steve. The drive shaft shop I use installed the U-joints a couple of years ago. I pulled the shaft out took it to the shop because he installed both of them for just a few dollars more then it was going to cost me for just the joints. I finally took the van to him and 2 or 3 months ago and he checked it with the van up in the air and then pulled the shaft and balanced it. It was a little out of balance and he welded weights on it. I did not check the slip yoke and didn't notice if he did or not. he did tell me to bring the van back if that didn't fix it. Perhaps I will take it back and have him check the pinion angle and check the balance while it is on the van.
It's not the front pump. If it were it would vibrate in neutral and park. Is there any fluid leakage at the rear transmission seal ? How'd you get an aluminum driveshaft in a van ? If indeed that's what it is, I'd recheck to see that those weights added are still there. Aluminum is really hard to make small welds stick.
no leaking at the tail shaft.. There is a tsb about the aluminum drive shaft in the 88 E150. Complaint: click/pop. Action: replace drive shaft. Well it is a little past getting ford to do that. The yokes were crimped on and they would click or pop or ting when under pressure. Mine may have been replaced because it has 2 what look like brads, big rivets, or welded in pins on each end where the yokes are crimped on. The drive shaft shop said there is no way it can slip.
The weights were on there last Tuesday when we rebuilt the differential. Right after the drive shaft was balanced the vibration seemed to have changed just a little. Hard to describe. Maybe like a forth of the harshness of the vibration went away.
Was thinking about harmonic balancer and or engine miss but since it went away when I put it in neutral at 65mph and the vibration was still there, I don't think it has anything to do with the engine.
I haven't changed the transmission mount but again in neutral wouldn't the vibration change a little, same for the leaf spring bushings?
Those are the two simple things left (besides checking the pinion angle) to change before revisiting the drive shaft shop and having him connect the EVA strobe light to check the drive shaft vibration on the van.
Remember the video
After that the transmission is the last thing left. I dont like the OD clunk as it feels like it is going to break something in the differential when it clunks.
One more thing... When the drive shaft shop had it on their lift, had it in gear and ran it up to 65mph, there was no vibration ike i feel when going down the road.
Is there a harmonic balancer on the front yoke ? Some had them. As for the vibration, you have to visualize in your head if the frequency is the same as a tire rotating or is it faster like 4 times the rotation of the tires ? If it didn't do it on the lift, that could be because the pinion angle had changed due to the axle hanging down vs where it is with the weight of the vehicle compressing the springs, so it may be a pinion angle issue. If it clunks going in and out of OD, that's not normal, you should feel nothing there.
No harmonic balancer on the front yoke.
At least 4 times faster then tire rotation.
Good point about the pinion angle;e and being on a lift.
About the pinion angle.. I was going to replace the leaf spring bushings a couple of years ago and bought stock bushings, they were too small in diameter. I think the van was in an accident on the right rear long before I bought it. If the springs were changed at that time, that could have affected the pinion angle..
A thread here that says adjusting the tv cable may fix the problem. If I put a pressure gauge on the tv port and lower the pressure then it will shift into OD around 35mph when just rolling down the road and that is not correct either. Most people say it is better to have too high of a TV pressure then too low.
I have been planing on changing out the transmission but just don't want to let go of the money! I did get a good quote of $2,041.00 for a jasper transmission installed and that included replacing the rear engine seal since they would be right there.
That mechanic drove the van and said to just drive it till it quits but I want the van to be up to long trips around the country....
No harmonic balancer on the front yoke.
At least 4 times faster then tire rotation.
Good point about the pinion angle;e and being on a lift.
About the pinion angle.. I was going to replace the leaf spring bushings a couple of years ago and bought stock bushings, they were too small in diameter. I think the van was in an accident on the right rear long before I bought it. If the springs were changed at that time, that could have affected the pinion angle..
A thread here that says adjusting the tv cable may fix the problem. If I put a pressure gauge on the tv port and lower the pressure then it will shift into OD around 35mph when just rolling down the road and that is not correct either. Most people say it is better to have too high of a TV pressure then too low.
I have been planing on changing out the transmission but just don't want to let go of the money! I did get a good quote of $2,041.00 for a jasper transmission installed and that included replacing the rear engine seal since they would be right there.
That mechanic drove the van and said to just drive it till it quits but I want the van to be up to long trips around the country....
I think I have a spare AOD yoke with a balancer, I'll send it to you if you want it. That may get rid of the vibes. I bought a driveshaft for a 2004 Mustang GT that was a factory leftover and it had one on it. I think I still have it, the only thing is you need to measure the O.D of your yoke's front portion, I've run across 28 spline yokes with different diameters, some are the same OD as a 31 spline yoke. The one I have is the larger 28 spline
Yes, some AODs and AODEs had balancers on the front yoke.
If it didn't do it on the lift then you changed two conditions: 1) there is no load through the driveline. As noted above, if the axle is at full droop then the pinion angle is different. Also, you have no load through the driveline. The rear axle tries to rotate with torque so it will change the pinion angle slightly just from trying to push the fan forward. If the leaf spring bushings are shot that will change the pinion angle excessively.
Also, a torque load compresses engine and transmission mounts which can amplify a driveline vibration.
And of course an ignition miss from things like bad plug wires or cap/rotor will first show up in Overdrive under load. And an ignition miss can certainly mimic a driveline vibration. Engine misses have fooled lots of transmission technicians who replaced torque converters only to find out it was a bad plug wire.
Ok, my mistake, the front shaft yoke does have a balancer.
The drive shaft shop locked the drive shaft in the balancing machine with both yokes on it, spun it, identified where the weight needed to be and welded the weight on. They spun it again to check it then installed it back on the van. HE said if it still vibrates, to bring it back and he will look deeper..
There is a damper on the axle housing that looks like this and appears to be in good shape..
As to the torque load engine and transmission mounts,,, along with engine miss vibration,,, Wouldn't those have been eliminated when I shifted to Neutral at 65mph on the interstate and the vibration was still there? Seems like in neutral, the torque load on the rear axle would have been eliminated also?
If the transmission mount was worn badly perhaps there could be dome vibration on coast? W lifted up and side to side on the tail shaft and nothing seemed to move on the mount.
Perhaps I should go a head and replace the shackles, spring bushings, rear transmission mount, and check the pinion angle next.
Since the converter bolts to the flywheel, its rotation speed is directly related to the engine speed.
I'll let you know about the yoke Baddad. I think I will make another appointment at the drive shaft shop first and see what he comes up with. Drive shafts is all they do besides springs... They have a machine for re-arching springs..
Ok, my mistake, the front shaft yoke does have a balancer.
The drive shaft shop locked the drive shaft in the balancing machine with both yokes on it, spun it, identified where the weight needed to be and welded the weight on. They spun it again to check it then installed it back on the van. HE said if it still vibrates, to bring it back and he will look deeper..
There is a damper on the axle housing that looks like this and appears to be in good shape..
As to the torque load engine and transmission mounts,,, along with engine miss vibration,,, Wouldn't those have been eliminated when I shifted to Neutral at 65mph on the interstate and the vibration was still there? Seems like in neutral, the torque load on the rear axle would have been eliminated also?
If the transmission mount was worn badly perhaps there could be dome vibration on coast? W lifted up and side to side on the tail shaft and nothing seemed to move on the mount.
Perhaps I should go a head and replace the shackles, spring bushings, rear transmission mount, and check the pinion angle next.
Since the converter bolts to the flywheel, its rotation speed is directly related to the engine speed.
I'll let you know about the yoke Baddad. I think I will make another appointment at the drive shaft shop first and see what he comes up with. Drive shafts is all they do besides springs... They have a machine for re-arching springs..
Yes, the vibration would change pitch if you shifted to neutral at speed, if it was engine related. And that should eliminate the torque load from the driveline. It was unclear in your previous post if it changed or not when shifting to neutral.
I am still betting its the driveshaft, possibly worn yoke splines. That looks like the OE yoke so its had plenty of time to wear.
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