P37 Chevy Chassis Vibration

[m.elliott63]

I mave a 1998 NRV Sea Breeze on a Chevy P37 chassis. I am getting chassis vibration (not steerig wheel) at speeds above 50mph. I have had it into a truck alignment/repar shop for front end alignment, fron tire balance check. While doing the alignment, they said the bell cranks need adjusting and a driver's side tie rod was shot. All of that was repaired and they mentioned possible changing the fron tires from a drive style to a steer style as this may be causing some of it. On the short drive home it seemed like the vibration was maybe worse. Since these tires were this way we purchased, and we needed a spare, I had 2 new Sailun 637 HWY ssteer tires put on and balanced. Drove the coach like 75 miles and the vibration was still there. I took it back to the truck shop and they said that my suspicion of U-joints or drive shaft was causing the issue. Once the got it in the bay, they told me the u-joints were fine but someone had taken the drive shafts out and put them back out of line. I had the rear pinion seal replaced and the differential fluid changed and the drive shafts reoriented. Started to drive home from the shop and turned around and went back. They told me when I paid that the vibration was 90% gone and one of the shaft sections had a slight twistbut not bad. My test drive found that they were 100% wrong on the vibration being gone. I left it with them to go back over and correct. Any ideas you guys have would be greatly appreciated. If anyone here is located in Indiana and can recommend a good place to take it to that would be welcome as well.

[Lifemember]

I also have a P37 and have no idea about the vibration although reading about others with the problem have changed out the tires and solved the problem.

As for the bell crank it can be adjusted for up and down movement but not side to side. They wear out between 15K and 30 K miles.

https://youtu.be/66s2s72m32g

https://youtu.be/fD-bT3OLPxY

[m.elliott63]

Ok...after taking my rig right back to the shop, here is what happened. Last Friday they removed and broke down the rear tires to make sure there was nothing inside. Re-mounted and re-balanced. They sent the entire drive shaft assembly (4 pieces) to a drive shaft specitaly shop. I just heard back today and the drive shaft was out of balance. We are supposed to pick it up this evening and they tell me that there was some improvement. We shall see this weekend when we take a little trip for a day or 2. If this is not improved, the only things left I can com up with would be the auto park brake drum or warped rear rotors. I report back next week.