New tires and new vibration in 4wd going over 50mph

[SpidermanGeek]

I think you may have found the cause of the grinding issue.

Yeah, the "CAUTION! Never push the “4WD” button if wheels are slipping. Stop the slipping or spinning before shifting." warning is plastered multiple times all over every page of the manual in the 4WD section.

Maybe its trying to tell us something, lol.

 

[MtnT4R]

I'm still confused about this speed & road condition stuff. It was news to me until recently that there was a recommended "speed limit" for H4 usage.

I quickly peeked at my owner's manual and this is the info that is listed in mine:



I have yet to find somewhere in the Owner's manual that states it is not recommended to go over 55MPH in 4WD.

Hitting the 4WD button simply engages the half shaft from your tranny to the front differential and feeds power to your CV axles, so technically speaking the top 4HI speed is probably the same as 2HI(I dont think I would ever suggest testing that). Most of the drive components are spinning whether you are in 2WD or 4HI, so they are obviously built to handle highway speeds.

I've driven snow packed interstate on a nearly daily basis, six months a year, for 14 years now, nearly always in 4HI, usually between 50 and 60 mph when conditions allow. Both mechanics and dealers have told me that the 55mph speed cap on 4x4 is typically a good rule to follow with much older vehicles(think locking hubcaps) but not required on modern drivelines.

If anyone better versed in 3rd gen mech specifics could speak up to correct me I'd appreciate it, but I've had zero 4x4 issues after putting hundreds(thousands?) of miles on 4x4 at 'interstate' speeds.

Honestly I would recommend driving in 4HI more often than you might find necessary in the winter simply because rear wheel drive is a much more dangerous drive configuration than front wheel drive in ice and snow. Just like pickup trucks, there is hardly any weight over the rear axle so you are much more likely to accidentally goose the throttle and break the rear loose, fishtail and crash. Engage that front axle and just make your lives easier.



OP, if you are getting vibrations when you engage 4HI, its most likely a balance issue with your 4wd half shaft(maybe you nailed it on a rock summer wheeling?), or your CV axles. Cant speak to issues with front diff or transfer case, never had problems in my experience.

If your 4HI seems to lag a bit before engaging, check/replace fluids in your differentials and transfer case. I did that in my '04 and it engaged and disengaged much faster and smoother. Also, when turning 4HI on and off, its best to do so around 25mph if possible, and make sure your foot is off the gas. Sometimes tapping the break a couple times will do the trick as well.

 

[atalarico]

Good info, all. To clarify, I don't think I've engaged 4wd when I've been slipping. I usually engage it when I notice the conditions could be slick and slipping could occur.

I'll have to take a look at the 4wd shaft then. What am I looking for exactly, just bumps or dings? I don't wheel on anything that crazy at all, so I'd be surprised if it was that. I'm guessing it's more likely the fluid or the CVs.

 

[Rock_Rat]

I'm still confused about this speed & road condition stuff. It was news to me until recently that there was a recommended "speed limit" for H4 usage.

You gotta love this: But honey, I have to go off road, it's in the manual! "You should drive in four-wheel drive for atleast 16 km (10 miles) each month. This will assure that the front drive components are lubricated."

 

[atalarico]

You gotta love this: But honey, I have to go off road, it's in the manual! "You should drive in four-wheel drive for atleast 16 km (10 miles) each month. This will assure that the front drive components are lubricated."

You can tell her that the driver is an integral part of the drive component and that it should be well lubricated each month! Gutter.

 

[MtnT4R]

Good info, all. To clarify, I don't think I've engaged 4wd when I've been slipping. I usually engage it when I notice the conditions could be slick and slipping could occur.

I'll have to take a look at the 4wd shaft then. What am I looking for exactly, just bumps or dings? I don't wheel on anything that crazy at all, so I'd be surprised if it was that. I'm guessing it's more likely the fluid or the CVs.

I'm pretty sure if your half shaft got nailed hard enough to throw the balance off it would have been a big enough event that you would remember.

Rock Rat has the more likely explanation. If you rarely use 4WD theres a good chance not all of the components are properly lubricated. That could cause some vibrations at higher speeds. Any chance you can isolate the noise? driver/passenger side/center, farther forward, does it only happen/happen more when you are on a straightaway or turning right or left?

Did you check your CVs for leaky boots? I thought I read that you rebuilt or swapped those out recently. That could cause anything from vibrations to some really gnarly grinding depending on severity.

 

[atalarico]

I'm pretty sure if your half shaft got nailed hard enough to throw the balance off it would have been a big enough event that you would remember.

Rock Rat has the more likely explanation. If you rarely use 4WD theres a good chance not all of the components are properly lubricated. That could cause some vibrations at higher speeds. Any chance you can isolate the noise? driver/passenger side/center, farther forward, does it only happen/happen more when you are on a straightaway or turning right or left?

Did you check your CVs for leaky boots? I thought I read that you rebuilt or swapped those out recently. That could cause anything from vibrations to some really gnarly grinding depending on severity.

I was about 1/4 of a quart low on oil in my front diff, so I just I topped that off. I haven't had a chance to see if it worked, but I'm hoping that does the trick. I realized that when I replaced my CVs back in July, I never totally topped off my front diff after because I was out of gear oil. I ended up buying another quart a week or so later, but I didn't top it off because I just found that same quart still un-opened.

If the vibration is still there I'm going to try to see if I can isolate the vibration to one side or the other.

I replaced my CVs over the summer with reman'd CVJ axles (red silicone inner boot and neoprene outer). The last time I did anything with my CVs was after my lift about 5 years ago when me and another forum member rebuilt the original CVs with CVJ boots. I really do question whether these reman'd ones are long enough. Same lift as I've always had, but the angle on the boots looks a bit more iffy than the last ones. I've been meaning to just snip the boot clamps and pull them further down, but that shouldn't cause any vibrations. Short CVs might, but I'm feeling like I would have a lot of other issues if that were the case.

 

[D Farms]

so have you had the tires rebalanced yet? it is possible that only one of the front tires was out of balance. I would also check to see if the pressure is the same in all the tires, a difference in pressure can cause a difference in tire diameter.

another thing to consider is that the front end is not designed to pull the truck and maintain alignment. the front control arm bushings are soft and allow the arms to move quite a bit. under 2wd conditions there is not much force on the arms so the bushings are not flexed and the alignment is maintained. in 4wd the front pulls the truck and the bushings flex and mess up the alignment. in a few words the truck was not designed to run in 4wd all the time.

considering this you may want to look at your control arm bushings and then replace them, i will warn you that its almost impossible to visually check this without taking the control arms off. if your bushings are bad you will enjoy a massive improvement in ride quality and handling after you have them replaced.

 

[atalarico]

so have you had the tires rebalanced yet? it is possible that only one of the front tires was out of balance. I would also check to see if the pressure is the same in all the tires, a difference in pressure can cause a difference in tire diameter.

another thing to consider is that the front end is not designed to pull the truck and maintain alignment. the front control arm bushings are soft and allow the arms to move quite a bit. under 2wd conditions there is not much force on the arms so the bushings are not flexed and the alignment is maintained. in 4wd the front pulls the truck and the bushings flex and mess up the alignment. in a few words the truck was not designed to run in 4wd all the time.

considering this you may want to look at your control arm bushings and then replace them, i will warn you that its almost impossible to visually check this without taking the control arms off. if your bushings are bad you will enjoy a massive improvement in ride quality and handling after you have them replaced.

Yeah, I got them from Discount so they do that during install. Pressure is same between the two front tires.