How important is drive shaft installation? I've always just bolted it up and gone on my way, but I was reading the FSM and noticed it recommends that you mark the bolts and studs for exact re installation. I don't remember seeing any balance washers on any cars I've done work on either. Work as in engine/transmission swaps, clutch work etc.

Stupid question, but could this be the cause of a mild vibration between 55-65 MPH?

 

it is the rotating assembly, but to be quite honest with how old this car is well at least these second gens. everything rattles on these things. the balancing will not be much a deal at this age...

 

I checked torque on every bolt I could think of under the car. The drive shaft has no play on the car. I'm wondering about wheel bearings though as there is a very slight bit of play in the front. On a side note (possibly related) there is a grinding/squeaking noise from the rear of the car when reversing. I checked the brakes and they seem ok.

The vibration is only slight, and just causes the interior bits to buzz and rattle a little. Nothing major, but I would love to fix it if possible.

 

I've dropped my driveshaft multiple times without marking anything and I have never had any vibrations at speed.

 

Mazda does balance the drive shaft, but its good practice to put everything back where you found it. i have seen a couple of T2's with extra weights/washers on the d/s bolts.

anyways if you think its the drive shaft and not the tires, then pull it and have it balanced

 

Could it be wheel bearings? What could the noise while reversing be?

 

Reverse gear?

 

It's definitely not a gear. Sounds like a squeaky metallic noise from the rear. About like if your brakes have surface rust on them from sitting for awhile. I'll check the breaks again, but I'm thinking other than that it could be a wheel bearing. It only does it in reverse though. Maybe a caliper is slightly sticky?

 

I've never had an issue with not marking it. I've also swapped driveshafts without an issue.