front end grind

[VXorado]

CVs usually pop/click and vibrate at speed when they wear out. Grinding is tough, it still could be the CVs but could be a lot of other things too.

I like the idea of finding some dirt and putting the VX in 4lo. I ran the VX with shot CVs and you'll definitely know they're bad when your in 4lo. If they don't pop/click, they're probably not the problem.

[tom4bren]

- tried the search on changing diff fluid but came up empty as far as how-tos go

The diff drop instructions just tell you to do it, not how to do it. Sorry.

It's pretty simple though. There will be a plug high on the differential & one low. The high one is the fill plug & the low one is the drain plug. Remove the fill plug first & then the lower one with a catch pan underneath. You may want to have a piece of cheese cloth to drain it through to catch any particles for later inspection. Remember, the hole can get clogged with gunk so you may have to poke at it to keep the oil draining. You'll need 2 bottles of 90 weight oil to put back in (IIRC it takes 1 1/2). You do NOT need the positrack additive for the front pumpkin but it won't hurt anything if that's all you can find.

Replace the drain plug. Start putting oil in the fill hole until it starts dribbling out. Replace the fill plug. Drive it for a day & then check to see if you need to add more.

EDIT:

The shop manual isn't much help either but you can find it here:

http://www.vehicross.info/modules.ph...warticle&id=20

Look on page 4A1-2 for diagnostics and 4A1-3 for a drawing of where the drain plug is.

[evillecutter]

you guys are awesome thanks a million gonna try to work on it tomorrow or wed and see what i can find -i'll let you know how it goes

[evillecutter]

had a buddy come over last night and drive it around while i stood outside and listened and its not coming from the front end it just sounds like it when you sit in the drivers seat - sounds like its coming from the drive shaft or u joints somewhere in the middle of the car - when i put it into 4wd low today it drove fine and didnt make the noise any worse like it did two says ago but still makes the same noise - like a popping sound - my buddy said it sounded like the cv's starting to go out but when i drove it and he stood outside and listened we both agreed its not coming from the front end but turning does seem to affect the intensity of the noise - any ideas?

[tom4bren]

If the sound intensifies while turning, then it's probably your outer CV. The sound can travel through the driveline and make it sound like it's coming from the driveshaft (hollow metal tubes are great for converting mechanical vibrations into sound waves).

That said though, it wouldn't hurt to hit your U-Joints with a grease gun before you tear into the CVs & see if that solves your problem.

Keep us posted.

[evillecutter]

greased all 3 nipples about 2 months ago - lifted front end and got pressure off wheels, tried to shake and no play (think bearings are good) - then tried to wiggle everything connected to anything in the front end that looks like it moves, including the cv joints and they are all stiff and feel good - is there anything in the drive shaft that could bind up or cause a grinding/popping noise? if just let the vx creep at idle speed you can hear it almost continous (ping ping pop ping pop) when you go faster it gets more intense and sounds like grinding

so the front cv joints could make a noise in the middle of the car? i hear nothing when i put my ear right up next to the front wheels when they are rolling...
are the joints that connect the shaft inbetween the front differential to the transfer case also called cv joints?
sorry to sound dumb but everyone i talk to calls all this crap something different

[tom4bren]

Well, it could still be CV because you're turning the wheel with the front end up so the CVs are riding in a different spot in the outer race.

It could be the front differential since it's function is to divide power between the two wheels even when they are spinning at different speeds (like in a turn). Does one wheel turn the opposite direction from the other when you spin it? Hold one wheel in place while spining the other & listen for odd noises in the differential.

I'd suggest draining the front pumpkin next and inspect what comes out to see if there are any metal flakes or even chunks of metal (that would not be good). If nothing else, it's a chance to change over to synthetic oil. One of the symptoms listed in the shop manual for low or dirty oil in the differential is a grinding noise ... so that's what we're all praying for.

BTW, there are even places you can send a sample of your oil off to & they can perform an analysis to determine if there is anything untoward happening in your diff.

BBTW, is your breather tube still attached to your axle tube? If that's missing, the oil could be contaminated with water.

[VXorado]

are the joints that connect the shaft inbetween the front differential to the transfer case also called cv joints?
sorry to sound dumb but everyone i talk to calls all this crap something different

Yes the front drive shaft uses rzeppa CV joints (same as halfshafts), the rear dirve shaft is u-joints.

When my CVs got really bad, the sound was more of a constant short, light clunk

clunk, clunk, clunk, clunk

I really don't know about:

ping ping pop ping pop

Definitely not what I heard with my CVs but that doesn't mean they're not the problem... in other words I have no idea.

On a side, this is why I got manual hubs. It really helps in troubleshooting & bypassing front end problems. With manual hubs, you could pull the front drive shaft and be completely rear wheel drive to help locate the sound. Alternatively, Jofotos has a method to disconnecting the front axles with a big sponge. Might be useful if you don't want the manual hubs but want to disconnect the half shafts for troubleshooting

[evillecutter]

the rear diff needs a special additive?

[tom4bren]

Yes. There is a special additive for Limited Slip Differentials. Most stores carry a selection of gear oil that already has it mixed in.

The jury is still out on whether it's needed if you are using synthetic but I've even seen the synthetic that already contains the additive.

[VX KAT]

Yes. There is a special additive for Limited Slip Differentials. Most stores carry a selection of gear oil that already has it mixed in.

The jury is still out on whether it's needed if you are using synthetic but I've even seen the synthetic that already contains the additive.

Yeah, I know Royal Purple has the additive and nothing had to be added when I had mine switched over to all synth. I'm not sure, but I think reading here somewhere that Amsoil does too...but would have to look into that.

[evillecutter]

finally decided its out of my rhelm of expertise/tools and took it to my guy - he is 75% sure its my front drive shaft and if its not that its prob something in the differential - he said if i find the drive shaft he will put it in for $60 which looks like its well worth it seeing as im pretty sure you need a special tool to compress the telescoping parts - i havent priced these yet seeing as i cannot find anyone that sells them... am i doomed?

[Scott Larson]

The "telescoping" part is just a slip-joint, it slides in and out to allow for length variations due to the articulation of the axles under compression and rebound. It is not spring loaded or under any pressure for or aft. It will take your mechanic about ten minutes to replace the driveshaft on a lift. Figure about twice that doing it in your driveway. No, you're not doomed. The front driveshaft can be rebuilt at any reputable driveline specialty shop for far less then a new Isuzu part. Just hit the yellow pages...Good luck!

[Triathlete]

Nope...shops will not rebuild our front shafts. Several have checked into it including myself. Has to do with the type of joint our shaft has. A used replacement from a recycler will run $50-250 depending on the place and mileage (i paid under $65the shipped for mine).
The job is very easy and straight forward...I believe there are 8 8mm allen head bolts on each of the flanges (front and rear). Might take a little force to get it out and then just slide the replacement in and put the bolts back in.

[Scott Larson]

Hmmm...the "Clutch And U-Joint" in Burnsville, MN. claim they've rebuilt Isuzu shafts (front and rear) with "off the shelf" parts, now I'm curious... If you can find 'em salvage in good condition for less then a hundred bucks, that's not a bad option!