Hi mudders,
Little background first. I bought this HJ47 emergency service vehicle (outback paramedic truck) and imported it from Australia. I drove it some before I left the country for close to a year. It drove fine but would shake a lot (I'm not talking about baby steering wheel shake; this is big bad daddy shake where you wonder if the thing is going to hold together) at highway speed (read: 60 mph/90kmh) if the highway surface was cement type in sections. The separation of the sections would start the shake. if I slowed down to around 50mph/70kmh, it would settle down and later I'd speed up again. Other than that, no shaking. When I returned from my closet-to-year long absence and started driving it again, it started this violent shaking of the entire cab around 40mph/60kmh. It starts it when it hits uneven road surfaces. Sometimes it settles down when I slow down or speed up a little, but a lot of times it gets worse until I hit speeds of 50+mph/80-85 kmh. So it's doing it several times during a drive of maybe 5-7 miles. Never does it below 60kmh/40mph. I have a hard time believing it's wheel balance. It's got to be something bigger than that (and in fact, the only shaking the steering wheel does is the same movement as the whole cab. Never by itself).
I don't know if the fact that the cargo box behind the cab is physically separate has anything to do with it (only attached to the frame but not the cab--but maybe same thing for a ute tray; never seen one up close), but I get the impression the two (cargo box and cab aren't in synch and that might be part of the problem--but maybe not).
The two rear tires have the same tread and the two front the same tread; virtually identical tread all four (but two manufacturers). Tomorrow, just for the heck of it to eliminate the balance possibility, I'll take it in to check wheel balance. the cargo box is all aluminum; it has heavy duty springs in the rear (9 leafs) and 8 in front. New Old Man Emu shocks in the rear and probably originals in the front. Has 90,000 kms/60,000 miles total (definitely original; thing's in great shape for its age--except the shake
.
Any ideas would sure be appreciated. I've included pics so you can see the rig. Thanks.
Little background first. I bought this HJ47 emergency service vehicle (outback paramedic truck) and imported it from Australia. I drove it some before I left the country for close to a year. It drove fine but would shake a lot (I'm not talking about baby steering wheel shake; this is big bad daddy shake where you wonder if the thing is going to hold together) at highway speed (read: 60 mph/90kmh) if the highway surface was cement type in sections. The separation of the sections would start the shake. if I slowed down to around 50mph/70kmh, it would settle down and later I'd speed up again. Other than that, no shaking. When I returned from my closet-to-year long absence and started driving it again, it started this violent shaking of the entire cab around 40mph/60kmh. It starts it when it hits uneven road surfaces. Sometimes it settles down when I slow down or speed up a little, but a lot of times it gets worse until I hit speeds of 50+mph/80-85 kmh. So it's doing it several times during a drive of maybe 5-7 miles. Never does it below 60kmh/40mph. I have a hard time believing it's wheel balance. It's got to be something bigger than that (and in fact, the only shaking the steering wheel does is the same movement as the whole cab. Never by itself).
I don't know if the fact that the cargo box behind the cab is physically separate has anything to do with it (only attached to the frame but not the cab--but maybe same thing for a ute tray; never seen one up close), but I get the impression the two (cargo box and cab aren't in synch and that might be part of the problem--but maybe not).
The two rear tires have the same tread and the two front the same tread; virtually identical tread all four (but two manufacturers). Tomorrow, just for the heck of it to eliminate the balance possibility, I'll take it in to check wheel balance. the cargo box is all aluminum; it has heavy duty springs in the rear (9 leafs) and 8 in front. New Old Man Emu shocks in the rear and probably originals in the front. Has 90,000 kms/60,000 miles total (definitely original; thing's in great shape for its age--except the shake
.Any ideas would sure be appreciated. I've included pics so you can see the rig. Thanks.
