'nother Question

[Lou85bronco]

85, 302 auto.. Drive shaft is new, rear end seems to look fine.. front end dis-engaged.. Im getting an odd vibrating feel when I'm running down the road 10+mph .. If I had my guess it would be the xfer case going out, or something along the lines..

Any suggestions? all ujoints are new.. just rebuilt the cvjoint in the drive,, needs ball joints up front.. but this feels like its coming from the mid/rear. If it is the xfer.. about how much do they run.. I'm guessing its a np208.. if so is there something better I could put in (besides an atlas) I dont have alot to spend but it may need a swap soon.. what other xfer cases will mount up right if any? and should I be looking to have mine rebuilt at a shop, or be easier just to go look for a junkyard or a rebuilt one?... thanks alot guys for the help so far... :blink:

 

[Seabronc]

By front end disengaged, I assume that you mean hubs unlocked and transfer case in 2WD.

Also, it sounds like you have replaced the frontend joints including the ones on the front drive shaft.

A vibration could be anything from slightly out of balance tires, a bad spot on a tire, bearings in the drive train, to the new driveshaft being slightly out.

For the drive shaft, You would need a runout gague or mount something that can hold a piece of chalk so that it is not quite toucning the shaft. Then lift your rear end up on jack stands and turn the wheels and see if the chalk puts a mark on any part of the shaft. That will tell you if there is a problem in that area of the drive train. I would do it at both ends of the shaft which should narrow down the possibilities.

The bottom line is that you could be spending a lot of money shotgunning the problem. So do some trouble shooting first.

Once you determine what it is, check with some reputable place like Jeff's Bronco Graveyard, LMC Truck for parts, or someone you know in your area that has a good reputation.

Good luck,

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[Lou85bronco]

A buddy of mine owns a very reputable machine shop here.. I know there is no problems with the front or rear shaft.. they have both been re-balanced twice for fault tolerance. Already had the tires shaved and balanced (cant add weight to my mag wheels) All u joints are new. As I said The rear end appears in fine working condition, but To save money I'm going to put a ner set of gears in them. If that doesn't do it.. looks like the transfer case is going to the paperweight category.... On the 85 302 auto, I've been told on the 8.8 rear end that it should have 3.08 gears in it.. what are the methods to finding this out?

 

[cryptonik420]

Does the rearend have a metal tag on it? clean it off and post up here what you find.

BTW, I can't see that the xfer case is gonna make those vibrations. You would hear more before you felt it in the driveline. Whining, chain slap or the like.

Xfercases are a joke to rebuild. You may just wanna do that instead. What kind of tires are you running that you had shaved? Just wondering because even if they get shaved and they are a big tire, then you are still gonna have vibrations. No tire is ever perfect. If the tire shop put the tire on the rim 180* backwards then it could have the effect of vibrations in the driveline. Like a guy stated before you can spend a lot of time can cashola troubleshooting these kinds of problems.

 

[Broncoholics]

I wouldn't think its the tires since it happens at 10mph. But how come the tire shop doesn't use stick on weights on the inside of the rim?

Is the vibration the same at speed or does it increase?

I had bad rear wheel bearings and rear pinion bearing in my 89 bronco. These both made a vibration but were easy enough to fix myself.

I don't think its the t-case at all, have you checked the fluid levels in everything?

Usually the pinion seal or t-case output shaft seal or yoke seal (depending on what you have)will leak if something is out of wack.

Do you have a lift and what size tires are these? I used to go thru u-joints every 3-6 months until I purchased some traction bars.

If the vibration goes away when hitting or letting off the gas its u-joints, light on the gas it vibrates. All the time its a bearing.

 

[Broncoholics]

Forgot to ask, did the splines on the drivelines get fixed or recoated? Check to see if there any movement by pushing on it where the shaft enters the driveline up and down or side to side? If there is movement in there it will vibrate.

 

[Lou85bronco]

The wheels can't be weighted because of the lip if they get a weight on there they leak so I had a 4x4 specialist shave the tires.. they are american racing 15x10 mag 4x4 rims 33 wrangler mt/r's

the vibration feels like a metal grinding vibration (similar to the cv joint on the shaft going bad).. but no noise and the shaft is in great shape.

I crawled under it today and saw that the case in front of the yolk entering the diff itself is damp, so i'm guessing its leaking at that seal.. If that be the case then the diff is probably dry and has been for a while.. looks like a rearend rebuild for me in the near future... :wacko:

 

[Seabronc]

The axle code is also listed on the truck safety compliance certificate on the driverside rear door post bottom line under "Axle". I believe that the 85 auto 8.8 only came with four possibilities;

18 = Regular 3750 pound capacity 3.08 ratio

19 = Regular 3750 pound capacity 3.55 ratio

H8 = Limited slip 3750 3.08

H9 = Limited slip 3750 3.55

If it is say 182, the 2 indicates limited slip front axle.

This assumes no one has changed the gears.

Good luck,

>-

 

[Lou85bronco]

Hey thanks alot.. Those codes will help with future refrence.. Only prob with this is the fact there is no sticker there lol.. thanks to the previous owners attempt at bondo (ALOT) and bodywork along with a cheap coverup paint job.. I dont have many stickers to work with.. Go NEWBIES! lol )

 

[Seabronc]

If there is no tag on the rear end, here is a way to find out.

Put the truck rear axle on jack stands.

Transmission in neutral.

Put a mark on the drive shaft at a point you can see it.

Turn both rear wheels at the same time and speed (need help for this, if you don't a non-locking differential will be doing its thing).

Count the number of revs on the driveshaft for one complete turn of the wheel.

If it turns just slightly over 3 turns, it is 3.08, If it turns slightly over 3 and 1/2 turns, it is a 3.55.

Good luck.

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