Okay, as some of you know, I just had gears installed in my truck a little over a month ago. Well, on Sat. I noticed my front left fenderwell looked wet after I parked. Didn't pay much attention to it. On Sun. after coming home from a short drive on the beltline, I noticed the fenderwell was now soaked and a puddle was starting to form on the ground. So I popped the hood and noticed a shitload of diff fluid had been leaking out the vent tube that was routed to the top front of the engine bay. It would only leak when I was driving.

In case you don't know, the truck is a silver '89 Chevy K1500 4x4 5.7 liter 350 CI Standard-Cab Fleetside Longbed with a grey cloth bench seat, grey dash, grey carpet, and the rear window is tinted 35%. I hope that is enough vehicle info

What in the hell would cause this? I haven't put it in 4WD since the gear install so the only thing that would be turning is the spider gears. I'm almost positive that the actuator isn't engaged due to the fact that it was replaced about a year ago and when it was bad, it caused the 4x4 indicator to illuminate. This is a new one on me.

9/12/2005 9:38:36 PM

if it had a blue interior, I could probably help you...

oh well

9/12/2005 9:48:50 PM

Who put the gears in it?? Hard to say shit without looking at it, somewhat similar symptoms on my car but it was from the CV joint seals being torn when taking the axles off for a clutch job

[Edited on September 12, 2005 at 9:50 PM. Reason : lalala]

9/12/2005 9:50:29 PM

sorry bud, i know jack about cars with 20%+ tint



i'll now leave this thread, so that people who might know what is wrong can talk

9/12/2005 9:51:48 PM

how much had it been driven since the gear install before you noticed it burping out the vent tube?

9/12/2005 9:58:56 PM

could it be as simple as the diff is overfull?

9/12/2005 10:02:37 PM

that was my first thought too, but if hes driven it much it would have shown up sooner than a month after

9/12/2005 10:04:27 PM

i put about 1500 miles on it since the gear install.

mike ellis (used to own carolina auto masters) did the gear install. i assure it was done correctly.

besides, how can you overfill a diff? you fill it up until it runs out.

9/12/2005 10:13:03 PM

well, it would have to be wayy overfilled too. i know mike does good work.

ok, anyway the first thing to do is pull the sight plug and see what happens. if its overfilled you have your awnser (or at least part of it) and if its low then you need to put some in anyway so you dont burn up your new gears on the way to durham to let mike check it over.

9/12/2005 10:23:55 PM

his house is in hillsborough I think...I only went out there once but its out that way

9/12/2005 10:27:37 PM

^it is, which is where my truck sits now. he told me to bring it to him yesterday after i noticed that. even he didn't have a clue as to what would cause that. he'll figure it out though. i just wanted to get some guesses.

9/12/2005 10:33:38 PM

I can think of a possible band-aid solution if nothing else helps; redline shock proof racing tranny/diff fluid (I'm not positive that they make diff fluid specifically). It has much higher surface tension than regular fluid, ie it doesn't get thrown off as easily. I've read about rally cars finishing stages with 0 fluid left in the transaxles having used this fluid. Nice piece of mind to have, though admittedly not exactly engineered for your application.
Ahmet

9/12/2005 10:42:27 PM

Here's something interesting...I had a Nissan Sentra many years ago. Kept popping out of fifth gear, so I pulled the tranny and put a new gear in it (and turned the syncro collar around). For a while after, I didn't really have any problems, but then it started blowing oil up the fucking speedo cable. Did it for a while, and then it quit. Fucking floor was WET with gear oil. I never did figure that one out.

You've got me curious now...

9/12/2005 10:45:00 PM

need more info. where's the vent come off? pumpkin or tube? what gears? same carrier/spider/side gears? if you actually used your 4wd, i'd first say water in the diff. but we all know that's not the case i've got a few other theories though depending on your answers...

9/12/2005 10:55:43 PM

you're driving a chevy.


bingo.

9/12/2005 10:57:18 PM

Ivan said what I might think: water in the diff.

Heats up, vaporizes, pressurizes axle, pushes oil out of tube.

I wonder if any worn bearing/out-of-balance shaft/cyclic action would pump air past a seal and pressurize the axle like that?

9/12/2005 11:17:23 PM

Quote :

"I can think of a possible band-aid solution if nothing else helps; redline shock proof racing tranny/diff fluid (I'm not positive that they make diff fluid specifically). It has much higher surface tension than regular fluid, ie it doesn't get thrown off as easily. I've read about rally cars finishing stages with 0 fluid left in the transaxles having used this fluid. Nice piece of mind to have, though admittedly not exactly engineered for your application. Ahmet"

$12 per quart at Autosport Gallery. They make a separate formulation for differentials. It's good stuff, I use it in my limited slip.

9/12/2005 11:26:40 PM

dont know about that water thing. or the bandaid thing. but one thing is for sure, if it isnt overfull, somethings getting in there.

[Edited on September 13, 2005 at 1:12 AM. Reason : or has gotten in there]

9/13/2005 1:12:23 AM

doubtful he has water in it. he doesn't take it 4 wheeling and it hasn't rained in what, 2-3 weeks? still waiting on his answer, there's a couple other things related to the gear swap it could be. oh, and the switching oil idea is terrible.

9/13/2005 1:24:12 AM

hydrogen bonding

9/13/2005 2:05:17 AM

wtf? You popped the hood? So this is your front axle vent? Why is your front axle turning? Do you have manual hubs and are they currently locked? Have you been driving down the freeway with your 4wd engaged? None of that shit should turn unless either the hubs are locked or the 4wd is engaged. My guess is that one of the hubs is hosed, and is staying locked, causing the gears to turn really fast, which is going to act like a pump if your diff is over full, and somehow push oil out of the vent? But 3 feet of oil head is a lot of pressure. So the next question, are you sure its your axle vent? not your transmission vent? or part of your pcv system?

9/13/2005 8:26:20 AM

does it have manual hubs?

[Edited on September 13, 2005 at 8:41 AM. Reason : ]

9/13/2005 8:39:59 AM

Older chevys front axles will turn all the time.

9/13/2005 11:37:59 AM

Your differential's NGR valve is either installed upside down or it is not closing properly and needs to be replaced.

9/13/2005 11:39:36 AM

his truck is a full time shift on the fly system. the side and spider gears will always turn.

9/13/2005 12:01:05 PM

on that model, the only thing that doesnt turn in 2wd is the front driveshaft and transfer case gears, but it still spins a little going down the road from friction even if its not engaged. and it sounds like to me the oil is getting super hot and foaming up, changing to a synthetic oil would cure the symptoms, but your front axle is still running too hot. even if it was correctly installed, there is always the chance of a defective bearing or gear tooth wearing or coming apart. when i built the ford 9" for my mustang, i had a similar problem, one of the carrier bearing races peeled apart in layers until it got so hot it welded itself together, with less then 500 miles on it. i could smell the oil burning, but it was redline so it didnt foam up. it shouldnt be hard to spot the problem, whatever is running hot enough to cause that will be discolored blue, and maybe even have oil burnt on it

9/13/2005 12:17:50 PM

Ahhh...that makes some sense right there...maybe too much preload?

9/13/2005 12:19:51 PM

so this things wheels are locked to the front axle full time, and the front drive shaft spins all the time? or the front drive shaft doesnt spin all the time and it has lockable hubs? If the front hubs are permanently locked and spinning the spider gear and front drive shaft the entire time its on the road, that seems odd. I can unlock the front drive train on my 40 yr old truck, did chevy move backwards in the 80's? Regardless, ~3 feet of head to over come, in a small line, is a shit load of expansion/bubbles. Not to mention all the volume within the axle. I call bs on the boiling oil theory. the pump theory is a bit far fetched. Seems like there is a lot of conflicting info here.

9/14/2005 12:14:42 AM

The deal is this: there is a dog clutch on the long side of the axle, actuated by a vacuum servo. When the xfer case lever is placed in 4wd, a vacuum switch activates the servo, which then engages the dog clutch.

In 2wd, the dog clutch is disengaged, and only one axle shaft spins in the diff. Only the spider gears turn. The diff, and therefore the driveshaft, remain motionless except for maybe some friction induced rotation.

They basically did it to allow shift-on-the-fly, as even auto-locking hubs ratchet in and out when engaged/disengaged or changing direction.

9/14/2005 12:19:50 AM

^zxappeal is correct again.

Quote :

"doubtful he has water in it. he doesn't take it 4 wheeling"

water is not in it. i can't take it 4wheeling. i can't keep stuff from breaking just from driving it down the road.

Quote :

"are you sure its your axle vent? not your transmission vent? or part of your pcv system?"

yes. i know the difference between 10W-30, 80W-90, and ATF.

Quote :

"does it have manual hubs?"

no, see zxappeal's answer in above post.



here is a pic i took sun. night of the mess it left on my driveway so you can get an idea of how much had leaked/sprayed out of the vent tube into the engine bay. again, it didn't leak when i parked. this is just run-off. this was after an appox. 10 mile ride.

9/14/2005 5:58:56 PM

have you checked the level yet? hot and cold? or felt it after driving to see if it is too hot?

9/14/2005 7:10:38 PM

the guy who did the install has it. i ain't fuckin with it.

9/14/2005 7:13:38 PM

still haven't answered my original questions yo...

9/14/2005 7:28:38 PM

you referring to these?

Quote :

"where's the vent come off? pumpkin or tube? what gears? same carrier/spider/side gears?"

the vent is off the top of the centersection or pumpkin, if you want to call it that. remember, i have IFS.
Yukon Gears, 4.10.
Stock Open Diff in front.

9/14/2005 7:35:52 PM

so the problem turned out to be the diaphram that the vent tube connects to was slightly turned. don't know how, don't know why. it was turned so it was perfectly lined up with the spider gears so they threw the fluid up the vent hole and out the top.

no, this wasn't an installer error or it would have happened right after the gear install. no, the diff wasn't overfilled, either. this is just one of those things. more proof of my bad luck is what it is. at least it didn't cost me anything.

9/24/2005 9:28:12 AM

thats not really bad luck

9/24/2005 11:29:16 AM

well ya gotta point there.

9/24/2005 3:16:56 PM

Well I'll be shitted like an elephant turd.

9/24/2005 10:09:02 PM