Differential fluid leak

gr_diver · 06-12-2005

My mechanic when topping up the differential fluid, he opens the plug towards the rear of the car, and fills it until the fluid is level with the hole. He then lets any excess drain and then tightens the plug. Is this the correct method?

I am asking because everytime he tops it up, there is fluid leak when I park the car from the differential's breather-valve for a few days, then it stops. Now that summer approaches I notice that it started dripping a bit sometimes, but just a dab. Maybe the extra heat is responsible. But why is it dripping anyway? Could it be a faulty breather valve? Or just excess fluid? Is his procedure correct?

Thanks in advance!

greensmurf20 · 06-12-2005

that seems to be the general accepted way, and the way i also do it on my own cars, same with manual transmissions. not sure why your rear axle would keep pushing fluid out through the vent cap tho, its not making complete sense.

mblackprowler · 06-12-2005

Sounds like you need a new rear. I have one with only 30,000 miles on it ! Check ad posted this site

jeff denton · 06-12-2005

When he tops it off, how much lube is he adding, and is it leaking anywhere else also?
I vented my axle more like how it is done on off road equipment, by tapping the vent hole to 1/8" pipe, screwing in a nipple, and running a 5/16 hose up thru the floor, up as high as possible and securing it at shelf level.
It hasn't dripped a drop yet.
This would work on any differential or gearbox of any kind, pretty common on real hard working equipment especially those running in dirty and wet environments.
On Speedway GT the vent was moved from the right side to the left side simply because the right tube is sealed way in next to the carrier bearing, that way all the oil isn't pulled into the tube by the G-forces of constant hard left turns, thus the vent on the right side would not be working.
Venting is important, when one gets plugged up the pressure builds up and you'll have a seal leak for sure!

greensmurf20 · 06-12-2005

mblackprowler:

your rear axle wont fit into gr_drivers car. he's in greece and shipping would be much more expensive than rebuilding his, as he has a 78' opel, theres no way it can be a GT, and therefore wont work since GT axles are GT specific.

baz · 06-12-2005

Originally Posted by mblackprowler

Sounds like you need a new rear. I have one with only 30,000 miles on it ! Check ad posted this site

had a look and can not find your ad where did you post it ?

jordan · 06-12-2005

Can fancy synthetic differential oil be used? if so what weight?

aknassassin · 06-12-2005

Is it possible to clean the vent hole with the little wire in it? Is it worth drilling and tapping the axle housing on the left side just to have second vent for street use, i'd hate to have a vent not work and blow a seal if I can prevent it.

gr_diver · 06-12-2005

no it does not leak anywhere else (e.g. from gaskets), just "discharges" the an amount from the valve, and then stops leaking. It hadn't leaked since October when it was last topped-up, until now that temperature rised about 15 celcius, and will stop again in a few days (stabilize in summer temperature -> new oil volume), and will not leak until topped-up again... Since it leaks from the valve, I can say for sure that the valve isn't plugged with dust-road debris...

baz · 06-12-2005

it must be just a little too full when topped up and sorts itself out when you drive

kwilford · 06-12-2005

what is the car on when he checks the fluid level? Is the car level? Maybe it is "tipped" forward such that it takes a bit more fluid than it should if it were level, and spits the excess out the vent?

jeff denton · 06-12-2005

By all means use synthetic gear lube whenever possible! The truck manufacturers insist on it, there must be something to it...
As for venting, were you to "hose it" as I described your problem is solved, trust me!

RallyBob · 06-12-2005

Originally Posted by jeff denton

As for venting, were you to "hose it" as I described your problem is solved, trust me!

Jeff's right, we always ran hoses from our rear differential and transmission vents into an overflow can, since under racing duress and summer heat we always had a little bit of 'puking' of fluids from the vents.

Bob

gr_diver · 06-14-2005

He raises the car on the kind of machine that has four "arms", which are placed under the cars jacking points. Which means that the whole car is raised, not just an axle. He does it this way, so while the engine oil is draining he tops-up the gearbox, the rear axle, inspects fuel lines, brake lines, wheel bearings etc.

So I don't think that the chassis is not level. I will check out what viscosity he is using, maybe it is wrong, so under the heat the expansion might cause the discharge...

By the way, that vent valve, does it have any mechanical parts or is it just a tube with notches on the end's sides that leave the excess pressure discharge through the cap?

Turbo X · 07-02-2005

your putting to much oil in it... have him check the oil with his little finger and bend at first knuckle, the oil should be at his finger nail, thats about a 1/2 in low... thats anough until the next inspection... the gearing is picking up to much oil and its spitting it out the breather tube.. as long as he can touch the oil it is fine..

06-12-2005	#1 (permalink)
gr_diver Senior Contributor Join Date: Feb 2005 Location: Greece Posts: 540	Differential fluid leak My mechanic when topping up the differential fluid, he opens the plug towards the rear of the car, and fills it until the fluid is level with the hole. He then lets any excess drain and then tightens the plug. Is this the correct method? I am asking because everytime he tops it up, there is fluid leak when I park the car from the differential's breather-valve for a few days, then it stops. Now that summer approaches I notice that it started dripping a bit sometimes, but just a dab. Maybe the extra heat is responsible. But why is it dripping anyway? Could it be a faulty breather valve? Or just excess fluid? Is his procedure correct? Thanks in advance! __________________ '78 Opel Ascona B 1.6SR ______________R.I.P.____________

06-12-2005	#2 (permalink)
greensmurf20 OPEL-LESS!!! Join Date: Mar 2003 Location: Gobles michigan 49055 Posts: 2,112	that seems to be the general accepted way, and the way i also do it on my own cars, same with manual transmissions. not sure why your rear axle would keep pushing fluid out through the vent cap tho, its not making complete sense. __________________ previousely owned 8 GTs and 1 manta. currently own 92 25th anniversary Z28. Ttop, 350, T56 swap, many upgrades, basically a complete restore. 67 chevy sportvan deluxe....next in line.

06-12-2005	#4 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	When he tops it off, how much lube is he adding, and is it leaking anywhere else also? I vented my axle more like how it is done on off road equipment, by tapping the vent hole to 1/8" pipe, screwing in a nipple, and running a 5/16 hose up thru the floor, up as high as possible and securing it at shelf level. It hasn't dripped a drop yet. This would work on any differential or gearbox of any kind, pretty common on real hard working equipment especially those running in dirty and wet environments. On Speedway GT the vent was moved from the right side to the left side simply because the right tube is sealed way in next to the carrier bearing, that way all the oil isn't pulled into the tube by the G-forces of constant hard left turns, thus the vent on the right side would not be working. Venting is important, when one gets plugged up the pressure builds up and you'll have a seal leak for sure! __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

06-12-2005	#5 (permalink)
greensmurf20 OPEL-LESS!!! Join Date: Mar 2003 Location: Gobles michigan 49055 Posts: 2,112	mblackprowler: your rear axle wont fit into gr_drivers car. he's in greece and shipping would be much more expensive than rebuilding his, as he has a 78' opel, theres no way it can be a GT, and therefore wont work since GT axles are GT specific. __________________ previousely owned 8 GTs and 1 manta. currently own 92 25th anniversary Z28. Ttop, 350, T56 swap, many upgrades, basically a complete restore. 67 chevy sportvan deluxe....next in line.

06-12-2005	#7 (permalink)
jordan Moderator Join Date: Mar 2003 Location: corning ny 14830 Posts: 2,182	Can fancy synthetic differential oil be used? if so what weight? __________________ 1970 Opel GT 1.9 1980 Moto Guzzi V50 2000 Saab 9-3 2.0 turbo 2000 KTM 200 exc STOLEN

06-12-2005	#3 (permalink)
mblackprowler Opeler Join Date: Feb 2004 Location: fairless hills,pennsylvania Posts: 1	Sounds like you need a new rear. I have one with only 30,000 miles on it ! Check ad posted this site

06-12-2005	#8 (permalink)
aknassassin Opeler Join Date: May 2005 Location: Tok, Alaska Posts: 28	Is it possible to clean the vent hole with the little wire in it? Is it worth drilling and tapping the axle housing on the left side just to have second vent for street use, i'd hate to have a vent not work and blow a seal if I can prevent it. __________________ '69 OPEL GT Rebuilt 1.9L w/ 5 Miles(rearend locked up on maiden voyage)

06-12-2005	#9 (permalink)
gr_diver Senior Contributor Join Date: Feb 2005 Location: Greece Posts: 540	no it does not leak anywhere else (e.g. from gaskets), just "discharges" the an amount from the valve, and then stops leaking. It hadn't leaked since October when it was last topped-up, until now that temperature rised about 15 celcius, and will stop again in a few days (stabilize in summer temperature -> new oil volume), and will not leak until topped-up again... Since it leaks from the valve, I can say for sure that the valve isn't plugged with dust-road debris... __________________ '78 Opel Ascona B 1.6SR ______________R.I.P.____________

06-12-2005	#10 (permalink)
baz opel free after 26 years Join Date: Jun 2002 Location: sunderland england Posts: 4,941 Real Name: barry williams	it must be just a little too full when topped up and sorts itself out when you drive __________________ Copyright © 2003-2009 barry williams All Rights Reserved save praying to God for sunday today we pray to Nike and run like hell

06-12-2005	#11 (permalink)
kwilford Über OpelGT.com Moderator Join Date: Mar 2002 Location: Calgary, Alberta, Canada Posts: 4,087 Real Name: Keith Wilford	what is the car on when he checks the fluid level? Is the car level? Maybe it is "tipped" forward such that it takes a bit more fluid than it should if it were level, and spits the excess out the vent? __________________ Keith Wilford working on my '71 GT and '75 SportWagon

06-12-2005	#12 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	By all means use synthetic gear lube whenever possible! The truck manufacturers insist on it, there must be something to it... As for venting, were you to "hose it" as I described your problem is solved, trust me! __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

06-14-2005	#14 (permalink)
gr_diver Senior Contributor Join Date: Feb 2005 Location: Greece Posts: 540	He raises the car on the kind of machine that has four "arms", which are placed under the cars jacking points. Which means that the whole car is raised, not just an axle. He does it this way, so while the engine oil is draining he tops-up the gearbox, the rear axle, inspects fuel lines, brake lines, wheel bearings etc. So I don't think that the chassis is not level. I will check out what viscosity he is using, maybe it is wrong, so under the heat the expansion might cause the discharge... By the way, that vent valve, does it have any mechanical parts or is it just a tube with notches on the end's sides that leave the excess pressure discharge through the cap? __________________ '78 Opel Ascona B 1.6SR ______________R.I.P.____________ Last edited by gr_diver; 06-14-2005 at 10:32 AM.

07-02-2005	#15 (permalink)
Turbo X Opeler Join Date: Jun 2005 Location: Plattsburgh, New York Posts: 91	your putting to much oil in it... have him check the oil with his little finger and bend at first knuckle, the oil should be at his finger nail, thats about a 1/2 in low... thats anough until the next inspection... the gearing is picking up to much oil and its spitting it out the breather tube.. as long as he can touch the oil it is fine..

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