4WD issue

[Rede]

I bought an 82 chev 3/4ton 4x4 as a winter beater and have had the truck 4x4ing several time with no issues... until friday.

I was heading to work with the hubs locked and in 4hi becaue the roads in town were pretty slick.

Made it about 3 blocks away from home when I felt a jerk/clunk/bang, which I chalked upto the truck just being an old lumber waggon and kept going.
It happened again 1/2 a block later so I slowed down to 40km/h and geared down into third, slipped the tcase into 2WD, then back into 4WD to ensure I had it fully engaged. Another 1/2 a block later it did the same thing.

I pulled over, looked under the truck for anything noticeable but couldn't find anything, put the truck in 2WD (left hubs locked) and carried onto work with no issues.

After work I put the tcase back into 4WD and again, made it about a block before the same jerk/clunk/bang. By this time I noticed that the problem seemed worse or more violent the fast I was going.

I picked dad's brain and he said I should check to see if the front and rear diff are the same gear ratio in the event that someone had swapped the front diff out. He said the rear diff in the older trucks were usually 3.07 and 3.08 in the front meening the front would pull slightly more than the rear when in 4WD...

Any suggestions on how I can verify that these diffs are the same ratio without pulling them apart, or tell if the front diff is the factory one? (maybe via a part number or shape of the front diff cover...?)

However, if the transfer case was binding, wouldn't this load the motor up much more on pavement and bind up soon as I started moving instead of a block down the road?

Can anyone suggest anything else I can check? (with in reason for)

I know the front right tie rod and right lower balljoint are completely fragged as well... could this play a factor?

[68Timber]

I'm not sure what transfer case you might have, a quick seach says it's probably an NP208. The only reason I looked it up was because the noise sounded like a chain-driven transfer case binding up and releasing. And it could/would do that if the gear sets didn't match front and rear. To be safe, pull the front and rear diff covers and count the teeth on the ring and pinion and make sure everything matches up. Keep it in 2wd meanwhile.

EDIT: The tie rod and ball joint could have been the spot of least resistance where binding up was released, but it would have had to let that tire slip to unbind and I think you would have felt that in the steering wheel when you head the noise. Do you recall?

[Rede]

Thanks for the quick reply and your bang on with the transfer case being a 208.

I thought it was odd that the right tie rod wasn't mentioned during the inspection that was done last month. The lower balljoint was noted but I was told it was still drivable as long as I wasn't doing any hiway driving. (which I don't) unless your right about those two things being the week link and they took a beating...

I'll have to limp around for now with the open rear diff (yay!) untill this -30C cold stretch eases up.

Do you think the chain or sprockets in the transfer case would be damaged?

Funny how I never had any issues with the fourwheel drive till now...?

[68Timber]

The chain/gear sets aren't necessarily damaged. First, it drives fine in 2wd and second, it's only a long distance guess that's what made the noise. But I'd make sure those front and rear gears match by visual count before I used 4wd again.

[Rede]

Thanks I'll update this thread when I have more info

[2tons of fun]

do you have the crappy auto locking hubs? they will do that when you smoke one.

did you even check the hubs or axle shafts for damage? you said that you have been wheeling.

you could have broke a shaft and it is wading up, you could have brooke a hub a it is wadding up.

pulling the diff covers to verify your gear ratio will also show you if you busted the ring or the spiders and cross shaft.

the only time i have a had a binding like that is when i busted a stub shaft like a hotdog bun. the shards would wad up and it eventualy egged out the spindle and destroyed it.

[Rede]

The truck came with Warn 1/4 turn hubs and aside from a few scratches, the hubs appear to be free from damage on the outside...
The drivers hub seems to be loose but I was unable to remove it due to siezed screws.
It was loose when I first got the truck and I was told that it should be okay but may get snow inside.

Weather here went from -10C to -30C just over the weekend and I'm not that hardcore to spend all night wrenching in the cold after I get off work at midnight. :s

[Rede]

Update:

no issues with hubs unlocked while transfer case is in 4hi... Pooched hub??

[68Timber]

Putting it in 4-hi engages the front drivetrain from the transfer case, turning the front driveshaft, then the front ring and pinion, and thus the front axle-shafts. But if the hubs are unlocked, the front tires are 'freewheeling' and not locked to the axle shafts. So even though the shifter is in 4wd the front hubs aren't locked and you aren't actually in 4 wheel drive.

[72lb4x4]

How slippery is/was slippery?

A part time 4x4 system such as this should only be used in 4WD when on mud, snow, etc. so that the natural binding of the system is relieved by slipping of the tires on the ground.

That means wet pavement is out...

Edit: I see you later said -30C, so my point may be meaningless in this case. Froze my ears a bit in that kind of cold once.

[Rede]

Originally Posted by 72lb4x4

How slippery is/was slippery?

A part time 4x4 system such as this should only be used in 4WD when on mud, snow, etc. so that the natural binding of the system is relieved by slipping of the tires on the ground.

That means wet pavement is out...

Edit: I see you later said -30C, so my point may be meaningless in this case. Froze my ears a bit in that kind of cold once.

:P

With an open diff and tired tires I can hold 1/2 throttle in third and leave a 10" wide glass like finish for over a block without breaking 40mph... it was pretty slippery


In another forum I was told that this truck likely has a 'corperate 10bolt' front diff...
Are there any ways of verifying this (besides opening the diff) so I can price out the proper replacement hubs?
I understand there was a 7.5" and 8.5" 10bolt made back in the day.


My plan is to try an easy-out and see if I can get the damn screws broke loose that hold the hubs together so I can inspect for damage and re-pack/re-grease everything liberally...

[2tons of fun]

7.5 10 bolt is a small truck rear diff.

your truck has a 8.5 10b front. it is smilar to the rear of a half ton but only the gears are interchangeable.

[Todersauce]

I bought a 67 a few years back for the same reasons. It would go like mad in a strait line in 4Hi but if you put an load on it (turning) or what have you the front diff would not work and make a horrible noise. I took the cover off counted the teeth and did an inspection and nothing ever seemed off, untill it just grenaded in there one day. I checked my carrier and it was broken enough not to hold a load but intact to hold it all together. It held together untill for a bit just something else to look at if you got the cover off!

[68Timber]

Rede, it still sounds like binding to me. I'd really like to know that the gear sets match before any further long distance diagnostics.

I live in Alabama and I hate to work in the cold and pretty much refuse to - and we don't have cold like you have cold.

Check it when you can and post back.

[Rede]

Thanks very much for the replies everyone.

This weather is driving me nuts. :s
Two weeks ago it was like -12C here, this week it's -28, this sunday they're calling for -34 for a HIGH and -42 for a low (that's -44F btw).... But Thursday has a low -32 and a high +2....!!
At least if the 14 day tread holds true, christmas eve should be around -2 for a high and -6 for a low.

Too bad my garage isn't heated and my car wasn't tucked in it... Then I'd say bring on the cold.

O whell.

I talked to a guy at a local shop about doing some on the side work like replacing a body mount, right ball joints and tie rod.
Meenwhile I'll see if I can peek in the diffs for a tooth cound and if I have time, pry into the hubs.
Warn stardard hubs are going to run me ~110 bucks but the 280 for premium hubs are out of my budget.

I've also been keeping my eyes open for a LSD for the 9.5" rear diff but there's lots of options and steep prices on some.

So much for just buying a low buck beater...?

Btw, you guys are a bad influence and my wife hates you all. Lol

[motornut]

if it helps i had some pics of my rear apart,note welds from previous owner....don't do it
note:used offset bearings to move wear area on axles

[raws67]

You could try locking one hub at a time while transfer case is still in 2 wheel drive. Maybee that would narrow down your problem. Just a thought.

[Russell]

Unfortunately it'll just send all the power to the wheel that isn't locked in...

Beautiful weather up here eh? -32 here in Edmonton this morning!

[Rede]

Originally Posted by motornut

if it helps i had some pics of my rear apart,note welds from previous owner....don't do it
note:used offset bearings to move wear area on axles

What all was wleded on in those pics?

Looks like something on the carrier, but maybe I'm not seeing it right...?

[Rede]

Originally Posted by Russell

Beautiful weather up here eh? -32 here in Edmonton this morning!

Well I don't know if I'd call it beautiful... lol
I was loving to single digit temps for sure and if it wasn't for the salt and sand on the roads, I contemplated putting the T/A back on the road.
i know.

I see that thursday has been upgraded to 0C to -1C with close to 1CM of freezing rain........


If the screws that hold the hub together are crusted in too bad and I just strip the heads, is there another way to extract the screws besides using an easy-out and maybe a hammer...? (I know two already are rounded pretty bad *whistles innocently* )

[Russell]

I purchased a set of reverse drill bits from Canadian Tire to get screws like that out. Most of the time the screw is more willing to come out than it is to be drilled out. If it does get drilled out, then you have a nice long stud to grab onto with some vice grips to remove them

[sierra4x4]

Not sure if this will help or not but my 86 3/4 ton 4x4 currently has 3.73 in the front and 4.10 in the rear. It is not noticable off road and in slick conditions but if I try to drive on pavement or a road with some traction the truck is almost imposible to keep on the road becouse the one front wheel withg the least traction always tries to spin. The thing pulls all over the road. If you have mismatched ratios you will know it.

[Rede]

Originally Posted by Russell

I purchased a set of reverse drill bits from Canadian Tire to get screws like that out. Most of the time the screw is more willing to come out than it is to be drilled out. If it does get drilled out, then you have a nice long stud to grab onto with some vice grips to remove them

Vera interesting... I've never heard of reverse drill bits, but it makes sence as the bit would bite into the screw, it would force it to back out. I know where I'm going tomorow.

i notice te lurching in 4wd while on slick pavement, going straight at a steady 50km/h (30mph). I don't recall the steering wheel pulling left or right... Just a lurch as if the was suddenly a moment of slack in the drive line and it was snapped back under load.
No issues keeping it straight at all.


Come to think of it... The first time I locked the hubs, I had a heck of a time getting the drivers side to turn and a buddy used his leatherman pliers to break it free. I'm really starting to think there's something wrong with that perticular one as the cap it loose as well.
Might be like my previous winter truck and full of sand. : \

[Rede]

Welllll....

I started the truck saturday to make sure it would start in this lovely -45F weather, which it did after a stalling twice.
I left the truck on a high idle of 1500rpm to warm up after a few minutes and went back inside to wait.

I peeked outside the window and notice no exhaust coming from the rear of the truck and stepped outside thinking it must have just stalled.

WRONG!

Lower rad hose split while running shooting rad fluid everywhere and after running for now more than 15minutes, then stalled.
I called a buddy for help and we replaced the blown hose and topped the rad up again.

Started the truck after he left and waited for the thermostat to open after warming up enough, but the rpms started dropping to around 500 or so and actually stalled once.
It fire up with no issues but the idle was really low and I still had no heat so I held it around 11-1200rpm for about 5 minutes and thought maybe it just needed to warm up more before maintaining a normal idle...

I noticed no change in engine temp AND my oil pressure was around 30psi at while somewhat idling instead of its normal 50-ish. Oil pressure was coming up when rpms picked up, so I thought maybe its just reading low for whatever reason and noticed that the gauge did climb when the rpms were brought up. Even took it for a test drive to warm things up and work any air bubbles out of the hoses and such.
Test drive went okay besides having to keep the rpms up at idle, but I did notice that it was pretty sluggish in third at lower rpms, but around 35mph/2000rpm it quit farting around and pulled pretty good once again.

I checked oil when I got home and noticed immediately that the recently golden brown oil was now BLACK and smelled like gear oil. So I'm guessing its really burnt...



I plan to change oil tomorow or friday after work and try it again to see how it runs now that the temps have warmed upto somewhere around 20F... maybe the carb was starting to ice up since it was so nipply and I didn't have any gas-line antifreeze in the tank at the time.


Anyone else had this kind of experience and can give me some sort of confirmation that its bad-bad, or tell me with some certainty that it'll be okay?


I started looking for used motors in the event this one is wounded and ran across a 99-ish chev 2500 van that has a 5.7L vortec and freshly rebuild 4L80E trans mission... He said the trany was completely rebuild, including stage 2 shift kit and brand new OEM converter for $3800 only 500kms before the van was replaced with a pickup.



Would the motor and/or trany be used in my 82 3/4 ton if I went with a carb style intake and looked into an auto conversion? (motor now, but would like an auto in the future)

Sorry for the long winded post and all the questions. = \

[Tony@AirRideTech]

Your front and rear gear ratios should be the same, another way to get ratio ( gets close ) is to put a chalk line on the pinion yoke to the diff housing. Then put a chalk line on the tire. Spin the tire 1 full revolution and then count the rotations of the driveshaft. If you do it front and rear, your yoke / diff chalk line should end up the exact same amount off. Keep in mind, this will only get you close but it will give you and idea of what you have.
Like I mentioned above, your front and rear axle ratios should be the same ratio. You should also be running the same identical tires front and rear. Even if you have a different manufacturer of tire front and rear but the same size, chances are they are a different O.D. which will cause binding at some point.
The next thing you need to check is the fluid level of your 208. It should be filled with fresh ATF to the second 30MM (?) plug. Some guys will convert this over and run a light 30 weight oil in them. I never have done this and i have changed my ATF about every 20-30K miles... and I have never had one issue with this gear box. 208's get hurt from low fluid. Any transfer case is going to get hurt from improper tire size or gearing ratios.