View Full Version : Rear main seal leak on 1996 Tahoe 5.7
My wife has a 1996 Chevy Tahoe and when I got up for work this morning I noticed the rear main leaking. Does anyone know of a good additive I can add? I do not want to take out the Engine or drop the pan to try and fix it. Thanks for your input.
Big Wall
10-20-2011, 14:05
I don't know of an additive, but if you are using synthetic oil it can make a car leak oil because it is so much more "slipery" than regular oil.
I don't know of an additive, but if you are using synthetic oil it can make a car leak oil because it is so much more "slipery" than regular oil. I have never used synthetic oil do to it being thinner thin conv oil. I dont even use it in my race Engines. I had a 1978 Grand Prix that would sling oil out of the timing cover all over the passenger side of the engine compartment, I used an additive and it stopped that very large leak. Now the the problem is I can not remember what I used.
SouthPaw
10-20-2011, 14:20
A rear main seal leak can really only be "slowed down." The only thing I have heard that actually works and some people swear by it is called "White Shepard." Advance Auto Parts on 10th street carries it and I think its around $50.
A rear main seal leak can really only be "slowed down." The only thing I have heard that actually works and some people swear by it is called "White Shepard." Advance on 10th street carries it and I think its around $50. If I could slow it down it would help just until I get healed enough to fix it the right way.
SouthPaw
10-20-2011, 14:25
try the white shepard
BPTactical
10-20-2011, 14:30
Pull the tranny, pull the flywheel, pull the seal retainer, replace seal.
Assembly is the reverse of the aforementioned.
Anything else is a waste of time and money.
try the white shepherd I found it online for 12.95 and I want to say I used bars leak the last time. I am not used to using stop leak to fix leaks, I like to do it the right way. I have had some recent accidents so it will be a bit until I can work on a car. Have you ever used Bars leak and if so how does it fair up to the White shep
herd?
mcantar18c
10-20-2011, 14:37
Please, don't use any stupid additives like "Stop Leak" (edit: Bars Leak, White Shepherd, etc. fall under the "stupid chit" category as well). It'll do more harm than good.
Do it the RIGHT way and replace the seal that's leaking. And before you write it off as your RMS, check everything to make sure it isn't something simpler like the oil pan gasket.
Pull the tranny, pull the flywheel, pull the seal retainer, replace seal.
Assembly is the reverse of the aforementioned.
Anything else is a waste of time and money. I will pull the engine before I do that just because I had my own business rebuilding the 700R4 200R4 4L60E and 4L80E transmissions. I used to do alot of those trucks and I hate laying on the ground and pulling the trans, and I am not in the physical condition to do it or I probably would go that rout one more time. I have it down to a science it only takes me a couple of hours to take it out and a couple hours to put it back in.
redneck122
10-20-2011, 14:49
While I agree, using a stop leak is never the best solution. But i've had customers who just couldnt afford to replace the seal.
Any auto parts store should have a few different brands. I've used one brand, i forget the name, but its an all white bottle that says "Rear main seal stop leak". It worked well for about two years, until the customer brought it back to replace the seal.
Please, don't use any stupid additives like "Stop Leak" (edit: Bars Leak, White Shepherd, etc. fall under the "stupid chit" category as well). It'll do more harm than good.
Do it the RIGHT way and replace the seal that's leaking. And before you write it off as your RMS, check everything to make sure it isn't something simpler like the oil pan gasket.I have seen enough rear seals leaks to know what the symtoms are. It is unlikely it is the oil pan gasket with it being the newer style. It will not hurt the engine to put in an additive that helps soften the seal. It is not like adding stop leak to the cooling system, which I just replaced the radiator cause I had a leak in it. I also have the rear differential leaking now, it sucks every time I fix a leak another one springs.
soldier-of-the-apocalypse
10-20-2011, 14:58
theres a reall good aditive i use it works EVERY TIME its called elbow grease its only .99 cents at the school of hard knocks
mcantar18c
10-20-2011, 14:59
I have seen enough rear seals leaks to know what the symtoms are. It is unlikely it is the oil pan gasget with it being the newer style. It will not hurt the engine to put in an additive that helps soften the seal.
LOL, a 1911 sniper and the Chuck Norris of the car world. Impressive.
What are the symptoms? Lemme guess... lots of oil leaking down the back of your engine, right? Could easily be an oil pan gasket, and you won't know unless you crawl under there and actually look at it.
And yes, more often than not putting a leak-stopping additive into a system on a car (be it the cooling system, the A/C system, power steering, engine oil, etc.) hurts more than it helps.
But hey, its your vehicle, do what you like.
It could also be the valve cover gaskets, the intake manifold, oil pan, oil pressure sending unit, or distributor gasket. Just to name a few. I'd bet it's the intake manifold gasket at the back of the engine leaking down onto the transmission or through the bell housing. Very rarely in my 7 years as a general technician specializing on GM trucks have I seen rear main seals leak. It does happen, but not too often.
Intake manifolds on 5.7 liter engines are notorious for leaking both coolant and oil. Also, cylinder head gaskets can leak oil. You would be wise to check thoroughly where the oil is coming from before wasting time and money getting it repaired.
Just my .02 cents as a former auto mechanic.
mcantar18c
10-20-2011, 15:25
It could be the intake manifold, heads, valve covers, etc., but the OP didn't mention coolant in his oil or oil dripping down under the transmission, as it would if the leak were above the trans and dripped down onto it and ran back down the housing.
It could also be the valve cover gaskets, the intake manifold, oil pan, oil pressure sending unit, or distributor gasket. Just to name a few. I'd bet it's the intake manifold gasket at the back of the engine leaking down onto the transmission or through the bell housing. Very rarely in my 7 years as a general technician specializing on GM trucks have I seen rear main seals leak. It does happen, but not too often.
Intake manifolds on 5.7 liter engines are notorious for leaking both coolant and oil. Also, cylinder head gaskets can leak oil. You would be wise to check thoroughly where the oil is coming from before wasting time and money getting it repaired.
Just my .02 cents as a former auto mechanic.I agree on the newer style small block it is very rare. I will check the possible leaks you have mentioned being that you are a Gm tech an know more about them then a pizza delivery boy. Thanks for your input I hope it is something else. I do not have much faith that it is anything else. It does only leak when it is running and oil is running out of the whole in the dust cover.
Coolant doesn't necessarily need to be in the oil for the intake to be leaking oil. The oil could be coming from the valley in between the cylinder heads. Also, oil will still drip straight down and through the bell housing and drain out of the drain hole in the flex plate cover. Got burned on that one once, had to do an intake for free.
You are right about oil running down the back of the trans too.
Coolant doesn't necessarily need to be in the oil for the intake to be leaking oil. The oil could be coming from the valley in between the cylinder heads. Also, oil will still drip straight down and through the bell housing and drain out of the drain hole in the flex plate cover. Got burned on that one once, had to do an intake for free.
You are right about oil running down the back of the trans too. It sounds to me that mcantar18c knows just enough to be dangerous.
Here is a quick rundown of how I do my transmissions just cause I am at work and bored. I start at the rear of the vehicle I first remove the 4 11mm bolts from the drive shaft, remove drive shaft. I then start on the front drive shaft, I remove the 4 11mm bolts holding it to the front diff and then the 4 16mm bolts holding it to the t-case. I then start on the T-case, I take the 6 15mm bolts off holding it to the rear of the transmission. I remove the 2 electrical connections that control speedo and 4wd, now I pull the t-case and let the fluid drain into a pan once it has stopped I slowly remove it lowering it onto my chest and then rolling onto the ground usually to the left of me and set it aside. Now I remove the 4 18mm bolts holding the cross member in and remove that as well. now I take a 8mm combo wrench and remove the 2 8mm bolts holding the wiring harness to the trans. I then dissconnect the electricle from the trans. Now I am ready for the 6 15mm bolts holding on the dust cover and the 3 bolts holding the torque converter to the flywheel. now I get a 4 foot extension with a 14mm deep well socket so I can get up to the the bell housing bolts and nuts holding the heat shield for the starter wires and the bracket for the 2 fuel lines and the dipstick. Now I remove the 6 14mm BH bolts, some times 7 on newer vehicles. I now jack the transmission up a bit to break it away from the dowel pins pull it back slightly and slowly lower the jack, pull jack out from under trans and drag trans to the custom made stand we have for rebuilding them. It has been awhile since I have done one so please feel free to tell me if I am forgeting something and if you want I can go into detail about how I build a racing transmission, or a trans built for big tires or pulling heavy cargo or what ever you want.
jerrymrc
10-20-2011, 16:36
I am going to reopen this but asking for help then going off on peoples answers is not the way to get anything done or the help one needs. Tired of this crap.
BPTactical
10-20-2011, 17:03
Its the blinker fluid reservoir.
GM products are notorious for it leaking[Tooth]
jerrymrc
10-20-2011, 17:10
Its the blinker fluid reservoir.
GM products are notorious for it leaking[Tooth]
I did my apprenticeship with a Corvair specialist back in the day. I know nothing of leaks.[Bang]
Its the blinker fluid reservoir.
GM products are notorious for it leaking[Tooth] Does that mean my muffler bearings are going out as well?
[ROFL2]
trlcavscout
10-20-2011, 17:11
You sure its the rear main and not the rear intake gasket leaking? Just asking. After working 9 years as a GM transmission then driveablilty tech the intakes are very common for leaking oil and antifreeze out the rear, especially if it has been replaced by a schmuck in the past who slid it on the silicone installing it.
I dont know about additives that work that good, I have never had any luck with them.
BPTactical
10-20-2011, 17:13
Does that mean my muffler bearings are going out as well?
[ROFL2]
I'm sorry, I don't give medical advice but a Proctologist should be able to assist you.
You sure its the rear main and not the rear intake gasket leaking? Just asking. After working 9 years as a GM transmission then driveablilty tech the intakes are very common for leaking oil and antifreeze out the rear, especially if it has been replaced by a schmuck in the past who slid it on the silicone installing it.
I dont know about additives that work that good, I have never had any luck with them. I know the Vortecs are prone to having intake leaks and I should use the updated intake gaskets. I did not really get a good look as I was wearing white pants and knealing down on a 300.00 wilson leather jacket, but I did see it leaking from the hole in the dust cover, and it only seems to leak when running. I had my wife take it in for an oil change and my friend who I used to work with works at grease monkey and he said it looked like the rear seal as well.
BPTactical
10-20-2011, 17:18
I know nothing of leaks.[Bang]
But as you age you are learning about them[Muaha]
Bailey Guns
10-20-2011, 17:27
Tried to resist....couldn't. Thread needed a little levity anyway.
UO9A4p1Qsvk
trlcavscout
10-20-2011, 17:29
Tried to resist....couldn't. Thread needed a little levity anyway.
UO9A4p1Qsvk
Now that is funny!!!
Tweety Bird
10-20-2011, 17:40
Quick thing to look at before you put any snake oyl in the motor, or yank some major parts out. Make sure your crankcase ventilation is OK. I had a 302 Ford once that leaked oil and it turned out the ventilation hoses were clogged; the pressure in the crankcase was pushing oil past the seals.
Not sayin' this is your trouble but it's cheap to check (that is, FREE) and also cheap to fix if necessary.
ChunkyMonkey
10-20-2011, 17:42
Duct tape.. nothing can't be solved by duct tape.
I did my apprenticeship with a Corvair specialist back in the day. I know nothing of leaks.[Bang]
The guy in the space next to my shop is THE Corvair specialist, been working on them since they were new. We may have a common acquaintance.
The guy in the space next to my shop is THE Corvair specialist, been working on them since they were new. We may have a common acquaintance.Why were those cars so dangerous? how did they get the reputation?
jerrymrc
10-20-2011, 18:20
Why were those cars so dangerous? how did they get the reputation?
They were not. The early 60-63 had one of those "if you do this and then do this the result MAY be this" 64's put a band-aid on it and the 65-69's were a dream. Ralph Nader wrote a book "Unsafe at any speed" along the lines of Al Gores "an inconvenient truth" We did not have the net to kill such rubbish back then. 60-64 were swing axle. 65-69 were a full IRS setup.
Kind of like some of the Jeep reports. If you go 70 MPH with low tire pressure and crank the wheel like this it may flip over.
I will say that a 65-69 Corvair with just a few tweaks would run circles around almost any American made car well into the 80's. There is a reason that they owned D-prod for 30 years and were the low-buck special at autocross events. My last one was a 66 with a crown kit. More race car than street but god was it fun to drive.
Put about 1 cup of sawdust in the oil filler tube. I assure it will fix the problem but you probably want to drive it straight to the dealer for a trade-off.
[ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1][ROFL1]
They were not. The early 60-63 had one of those "if you do this and then do this the result MAY be this" 64's put a band-aid on it and the 65-69's were a dream. Ralph Nader wrote a book "Unsafe at any speed" along the lines of Al Gores "an inconvenient truth" We did not have the net to kill such rubbish back then. 60-64 were swing axle. 65-69 were a full IRS setup.
Kind of like some of the Jeep reports. If you go 70 MPH with low tire pressure and crank the wheel like this it may flip over.
I will say that a 65-69 Corvair with just a few tweaks would run circles around almost any American made car well into the 80's. There is a reason that they owned D-prod for 30 years and were the low-buck special at autocross events. My last one was a 66 with a crown kit. More race car than street but god was it fun to drive. I always wondered if you could make them fast. How were they from the factory?
jerrymrc
10-22-2011, 15:59
I always wondered if you could make them fast. How were they from the factory?
Not bad but do remember that just a simple wheel and tire upgrade along with a st of shocks does wonders. A pic of one of the crown cars. Mine rode on 15X8 and 15X9 rally rims with the fenders rolled. Big bars and Koni shocks.
http://i884.photobucket.com/albums/ac44/jerrymrc/cars/001Medium.jpg
THe Yetti
10-22-2011, 19:39
For what it's worth brake fluid will swell rubber seals up and stop leaks sometimes. I have no Idea how it affects the engine oil, but it does swell seals and stop leaks. It has worked for me, but I've never tried it on anything I cared about.
Not bad but do remember that just a simple wheel and tire upgrade along with a st of shocks does wonders. A pic of one of the crown cars. Mine rode on 15X8 and 15X9 rally rims with the fenders rolled. Big bars and Koni shocks.
http://i884.photobucket.com/albums/ac44/jerrymrc/cars/001Medium.jpg That is beautiful
jerrymrc
10-23-2011, 06:16
That is beautiful
Back in 69-70 hot rod got a stock corvair (140-4 speed) to run low 14's with just some bolt on's. One thing people forget is they did not need a bunch of horsepower. they only weighed 2500 lbs in coupe form.
Even after adding the V8 in the back seat my crown car was only 2700 because we took out weight elsewhere. BTW the car in the pic has over 500 HP.
For what it's worth brake fluid will swell rubber seals up and stop leaks sometimes. I have no Idea how it affects the engine oil, but it does swell seals and stop leaks. It has worked for me, but I've never tried it on anything I cared about.
Brake fluid won't just swell seals, it will balloon them until they are absolutely useless.
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