Chevy & GMC Vans

Hi guys, I've been getting a weird vibration at highway speeds. But it's not an "all the time" thing.

I'll be cruising at 105km/hr on my way to work, and suddenly, it's like I've hit the grooved pavement at the edge of the road. Souns like vrrrrrrump! only for a couple seconds, and then stops. Happens whiles cruise control is set or not, tow/haul on or not, never happens below 75km/hr. but not all the time, couple of seconds at a time. then it goes away, drive another kilometer, does it again, goes away

The other night it was worse. I thought the van was tripping over its own front wheels, but than yesterday, barely anything.

So here's the back-round info.
2003 awd lifted 215/85/16 tyres.
Just changed out the burnt gear oil in the front, swapped in 75/90 Lucas synthetic gl5. Though I don't thinks its fluid related as it happen before change.
New moog sway bar links and bushings

Any ideas?

Also, it reminds me of when a friend of mine sunk his 2011 jeep jk in 40 inches of water, the torque converter had water in it or something and he never changed the tranny fluid after. At highway speeds it did a very similar thing.

I'm gonna need to do a long haul soon, as my grandfather just passed away, so I have a 500km round trip coming up, and I don't want to break down halfway.

Thanks again.
Shane

Sounds like a possible stuck caliper up front. I had the passenger side stick and it acted just like that. At low speed it didn't overheat the disk but at 80 the front tire started to dance and lock up with the extra heat.

huh, could it be that easy?

Kidhauler wrote:Sounds like a possible stuck caliper up front. I had the passenger side stick and it acted just like that. At low speed it didn't overheat the disk but at 80 the front tire started to dance and lock up with the extra heat.

I doesn't feel likes its pulling, but the calipers are original (230,000km), new pads, and pins, and anti rattle gear about 3 months ago. but that being said, when I removed the caliper from the bracket, one of the OE slider pins, was seized to the bracket, and I broke the rusted nipple trying to bleed the system.

I check for heat spotting today.
(now that you mention it, I go to the river almost everyday for a drive, and there is a 100ft water crossing, A LOT of steam comes off the frt pass. wheel when I hit the water, but none noticeable from anything else could be water hitting the exhaust though, it is 20" deep.).......

Take it for a drive of about 10km and get some decent speed then stop and feel the rims of o e is hot and the other cold that's the problem. My passenger side was so hot I nearly burnt my hand when I grabbed the hub. Calipers are only about $20-25 if you had that much problems with rusty parts it sounds like good money spent to swap them out.

update.
haven't been driving my van above speeds of 70km/h for awhile now, two days a go, my abs light turned on. after researching causes, I decided to do the easy suggestion first.

check my brake fluid level.
my fliud was black, blacker than I ever seen, and right on the minimum bar. ( I look at my wifes matrix, hers was pristine pretty good for 100,000km.)
I have learned from working at a midas as a teenager, that brake fluid doesn't magically disappear from the syetem, it goes somewhere, so if there are no leaks, chances are your pads are done.

I knew the fronts were fine as they are 5months old, so I replaced the rears as they were toast.

brakes went really smooth, except that all of my bleeder screws are seized or broken, so I wasn't able to properly bleed the system.
rear pads were toast. especially the passenger side. got everything back together, and I have a hard peddle, before the peddle would move a good inch before it really felt like it was braking. now just a light tap slows me down. but...

The abs light is now out. I will be inspecting my front brakes when I do the u joints today, as well as a balljoint relocation, my "new" upper d/s has decided to split a boot, and every time I grease it just flows out eventually. ill actually have pics to post after im done today.

Since it is in the Weird vibration part subject, i was wondering if anyone can shine the light on my close to same issue.

I just bought a new Gmc Safari AWD van "1998".

A lot got done to it lately as i have read some of your postings and all and just recent;y replaced my front breaks to eliminate that weird vibration" new pads, new rotors and new Callipers". Sadly enough, it didn't solve the issue.

Here is a list of what i have done to the van since it hit my drive way.

New radiator, new motor oil, Flushed all the drivetrain, tranny has been serviced "it was black" and still have the hard shift from 1st to 2nd, both diff have been flushed and put in a new fluid, TC has been flushed and put in ATF fluid.

This is as far i went so far with it.

The vibration is similar to if you were driving on a grooved asphalt when i drive over 60KM/h

I checked the motor mount and it looks new.

I do have a spare tranny and TC for it. If anyone have some kind of an idea of what it might be, it will be a huge help.

Thank you

Pull the rear drive shaft and check the joints.

LiftedAWDAstro wrote:Pull the rear drive shaft and check the joints.

Never thought of that one, will definitely check it.
Thanks lifted

well did a lot to it and the vibration is still there

here is a little vid
https://www.youtube.com/watch?v=q2FaaHQ ... e=youtu.be

hopes this helps

Sometimes the exhaust pipes can move & amplify the normal vibrations of the V6.

Could a combination of a bad body mount and bad Motor mount cause a bad vibration? i will later on post here my under body shot of the van while driving "fucking cool by the way" as you will notice a huge body motion with a motor mount vibration later, could this be also my culprit for my bad Vibration between 60 to 100 KM hr hwy driving?. will post the vid once it is done, but i pretty much concur that is the problem in this situation.

i also notice later on that i also have a bad lower control arm bushing, upper would also be bad.

AquaAngel wrote:Could a combination of a bad body mount and bad Motor mount cause a bad vibration? i will later on post here my under body shot of the van while driving "fucking cool by the way" as you will notice a huge body motion with a motor mount vibration later, could this be also my culprit for my bad Vibration between 60 to 100 KM hr hwy driving?. will post the vid once it is done, but i pretty much concur that is the problem in this situation.

i also notice later on that i also have a bad lower control arm bushing, upper would also be bad.

Here it is
http://www.youtube.com/watch?v=7QNgL1Ze ... load_owner

you can see that the body have a lot of movement and also the motor and tranny have a lot of movement. wondering if that could be the issue, Mounts in general ...

just found out today that my CV shaft are loose, bought some new ones.
Anyone knows the proper procedures for replacement?

Thank you

Loosen the center nut (don't use an impact), jack up front, remove wheel, remove rotor and caliper (tie up out of way), disconnect the upper ball joint from steering knuckle (support lower control arm with jack), use a drift or block of wood to tap on the inner metal tripot housing (near diff) until cv pops out, remove from hub splines. Sometimes the shorter inner splined axle will stick in the cv when removing. That's the gist of it anyway.

The washers/nuts are one use only, consider replacing seals as well.

Thank you for the info, will work on it before the snow comes falling down, looks simple enough