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EDIT: Read post: http://ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/41968-86-volvo-740-turbo-vibration-and-noise-issues?start=70#83381
Greetings all the way from Norway!
I have an issue with my 1986 Volvo 740 Turbo Intercooler that I can’t find any solution to. When driving past 60 km/h the car start to vibrate. I have had my car to a couple of different workshops, but none have managed to get it fixed.
Thought I could mention some technical specs about the car.
Engine – B230ET (134kW, turbocharged)
Injection system – Bosch Motronic ML 1.0
Gearbox – M46 (manual 4-speed + electric activated overdrive)
Rear axle – 1031 (torsen differential)Here is a runthrough of what I’ve done so far:
* Replaced every bushing on the car.
* Replaced engine mounts and gearbox mount.
* Replaced bushing and bearing for the driveshaft.
* Replaced the gearbox with one driven approx. 100.000km
* Replaced the differential and had the rear axle at the Volvo dealer to check for slack. Found well within tolerance.
* New tyres and rebalanced them.
* Changed wheel bearings.
* Changed rubber coupling (hardy coupling) between the gearbox and driveshaft.There have been vibrations since I bought the car 10 months ago. It is a common problem that the bushing for the driveshaft goes bad (which causes vibrations), so I didn’t really see that as a problem. After changing it I also realized that the driveshaft had a loose piece inside it that were impossible to remove. I then bought a used driveshaft. The vibrations were now less intensive, but very noticeble. I then replaced much of the things mentioned above, without any luck. Had it at a workshop to get the issue sorted out, the driveshaft were then replaced again with another used one. Got the car back as “fixed”, but there were still vibrations. Turned out the workshop installed it wrong (splines mismatched the balance markings. I corrected that, now the vibrations are almost gone, but are still there. Doesn’t look like any workshop know how to fix a RWD car anymore. None have equipment to measure angles etc.
Any suggestions on what to do here? This have been bugging me for a long time and won’t give up until it is fixed!
– Frank
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when you say vibrate. where exactly do you feel the
vibration? steering wheel,seat drivers/passengers?
Found this link. see if it helps.You feel it in the whole car, but most noticed in the seats. I feel it coming from underneath the car. It does not feel like wheel imbalance. When driving at 80 km/h and over the vibrations are felt less or is gone. It is worst between 60 and 80 km/h. At 80 a faint humming/drumming sound can also be heard that follows the vibration.
I read through that link, but it did not say anything I haven’t tried. I have no tools to measure the precise angles for the rear axle pinion. Nor do any workshop have tools for this. I guess the only thing I can do is to fiddle with the driveshaft and try it spline for spline. Very annoying that the workshop had to mess that part up. I don’t know if it exist any workshop that can balance driveshafts either, none I’ve spoken with can do this.
I know that the holes for the bolts in the rear end of the driveshaft/rear axle are offset, so that it can be assembled only one way there.
I could also mention that the previous owner had welded together the differential. This were, as mentioned, replaced and checked. Might the axles inside the rear axle be warped a little bit as a result of the welded differential? If they at all are long enough to cause vibrations.
You may want to take it to a Volvo dealership. They would be more likely to have encountered this before.
There are machine shops that could balance the driveshaft.I spoke with the local Volvo dealer a couple of weeks ago, but they were hesitant to take the job. They have another customer with a Volvo 960 that also have vibration issues, that they haven’t been able to fix. They also told me that those who work there are young and not experienced with older Volvo cars.
Had a word with the Volvo dealer today. I were told it is a pain to get that fixed since it is much trail and error involved. Costs and time could not be guaranteed. They have time to look into it in January, hopefully they’ll get it fixed. I’ve done much of the work already, so anything now would be to measure angles or get the driveshaft balanced I think.
The vibrations are probably not healthy for the bearings in the gearbox nor the rear axle?
First, vibrations are caused by rotating assemblies NOT alignment angles. There seems to be a big misconception on that. Given that your vibration is speed related I would guess it to be in the driveline. I know you’ve done many things there to address it but have yet to find it. That said don’t rule out a tire or tire balance problem as well. In fact that should have been the first place to check in my opinion. Given it’s age it could also be an issue inside the transmission or differential. As the dealer pointed out it will be a process of elimination that may take some time to properly diagnose.
Keep us posted.
[quote=”thisisbuod” post=43083]I’m pretty sure if the alignment is off enough it can produce vibration at a high rate of speed.[/quote]
No, it won’t. Alignment angles are just that, angles. Vibrations are caused by rotating assemblies. Alignments are not where you look if you have a vibration issue, you look for rotating assembles that are out of balance.
I delivered my car to the local Volvo dealer for checking. They found out that one of the rear wheels where not in balance when rotated. I have now given them my summer wheel set to check if the problem persists. I also delivered a new set of axels for the rear axle, as they might be deformed. The differential have been welded on this car, so it might be a possibility. If this still does not fix the issue, they’re going to send the drive shaft away for balancing. They don’t know where to do this as the local shops are out of business now.
I were also told by the mechanic that there will always be some vibrations in rear wheel driven cars. The drive shaft will always shake a little bit. This sounds a bit odd to me.
Spoke with the workshop today. They tried the summer wheels, with no luck. They replaced the axles inside the rear axle, without luck. Their conclusion is that the problem is the drive shaft it self. They’ve now ordered a brand new one since it were more expensive to rebalance the one I have. Hopefully it will arrive in a few days time.
The differential looked something like this when I took off the lid:
Absolutely hideous to drive with, and not to mention illegal. I changed out the differential with one gone about 160.000km, and had the rear axle checked for any slack or bad bearings. Had the rear axle at the Volvo dealer in the summer, and found to be well within specifications. I didn’t change the axles going to the wheels from the differential (as they were not damaged from the welding). This is a solid rear axle, so they are on the inside. I were told later that these have a tendency to get deformed because of the unnatural stress inflicted from the 100% locked axle.
That was some butcher work there. The rear is back
the way it should be. when you swapped it.They welded
all the planetary gears. WOW :woohoo:Got a phone call today from the workshop. The new drive shaft were not complete, and a few other parts had to be ordered. They just wanted to let me know of the costs and my options. Since most of the parts have arrived already, I told them to get the rest. I’m tired of used parts which can’t be trusted, that’s why I buy everything new. With the extra parts it will be a little bit more expensive now than to re-balance my current drive shaft.
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