Trans oil for limited slip diff

Drew20

Drew20

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Whilst I've got the car in the air, I should replace the diff oil as I've not replaced this in my ownership (3 years). I've read (on bigcoupe) that Castrol Syntrax limited slip 75W-140 is the stuff to use. I assume our earlier diffs are similar to the later E24 ones. Actually, come to think of it, post '82 E24s no longer used our side loader type of diff. But I think I used this syntrax oil in my '81 635, back in the day.

Are there any views on limited slip diff oil out there in the E9 collective?
 
Drew20 said:
Whilst I've got the car in the air, I should replace the diff oil as I've not replaced this in my ownership (3 years). I've read (on bigcoupe) that Castrol Syntrax limited slip 75W-140 is the stuff to use. I assume our earlier diffs are similar to the later E24 ones. Actually, come to think of it, post '82 E24s no longer used our side loader type of diff. But I think I used this syntrax oil in my '81 635, back in the day.

Are there any views on limited slip diff oil out there in the E9 collective?
Click to expand...


drew
as it is extremely simple do it, please
 
Hi Jesus, yes for sure the oil will be drained and replaced. The question in my post was more aimed at confirming the best oil to use for a LSD
:)
 
Drew20 said:
Hi Jesus, yes for sure the oil will be drained and replaced. The question in my post was more aimed at confirming the best oil to use for a LSD
:)
Click to expand...

oh, sorry, yes

i found two differente castrol products: syntrax / axle Z

the difference seems to be syntrax =hypoid, Axle Z = non hypoid

is your lsd hypoid or non hypoid,...that is the key

1609837894833.png




1609837938601.png
 
deQuincey said:
oh, sorry, yes

i found two differente castrol products: syntrax / axle Z

the difference seems to be syntrax =hypoid, Axle Z = non hypoid

is your lsd hypoid or non hypoid,...that is the key
Click to expand...

Thanks Jesus, I have no idea if a factory LSD is hypoid or not. Not even sure what hypoid means!! But I'm sure I can find out, will post back on my research.
 
Ok, hypoid means that the input and output axes do not intersect, i.e. they are offset. In my diff (all our diffs?) the prop enters the diff below the axis of the half shafts, so I'm hypoid!
 
Done, as Jesus says it's not a big job. I sourced the Castrol syntrax 75w-140 from Opie.
Dry fill for our diffs looks to be 1.5 litres (source E3 Haynes manual). I got about 1.2 litres in before it started running out the fill hole, which is less than I had anticipated.
I torqued fill and drain plugs to 55Nm (source E12 Haynes manual) with a fresh crush washer on each.

....and I didn't spill a drop, which is a real achievement for me!
 
Drew20 said:
Done, as Jesus says it's not a big job. I sourced the Castrol syntrax 75w-140 from Opie.
Dry fill for our diffs looks to be 1.5 litres (source E3 Haynes manual). I got about 1.2 litres in before it started running out the fill hole, which is less than I had anticipated.
I torqued fill and drain plugs to 55Nm (source E12 Haynes manual) with a fresh crush washer on each.

....and I didn't spill a drop, which is a real achievement for me!
Click to expand...

well done,

i am curious about how did you pour it into the filling hole,
it is a science and i am nit very happy with my own method

enlighten us, please
 
deQuincey said:
well done,

i am curious about how did you pour it into the filling hole,
it is a science and i am nit very happy with my own method

enlighten us, please
Click to expand...

After I cut the end off the conical 1 quart bottle cap I slip a short length of plastic tubing over it. I insert the other end of the tubing into the fill hole, elevate the bottle above the fill hole inverted and squeeze the contents out of the bottle into the housing.

15-05963.jpg
 
Mike Goble said:
After I cut the end off the conical 1 quart bottle cap I slip a short length of plastic tubing over it. I insert the other end of the tubing into the fill hole, elevate the bottle above the fill hole inverted and squeeze the contents out of the bottle into the housing.

15-05963.jpg
Click to expand...

than k you
that is the way i do it
not very comfortable but it works
any other way ? anyone ?
 
Other ways? Well Mike is using gravity as the force to push the fluid in.
Physics offers three other forces: electromagnetic, weak nuclear, and strong nuclear.
Electromagnetic could be to use an electric pump. I think weak and strong nuclear would be overkill and expensive.

Now, if you use a pedal air pump to push the fluid, guess which of the above four forces you are using.

PS: Resentment is technically not a force, just a powerful motivator.

deQuincey said:
than k you
that is the way i do it
not very comfortable but it works
any other way ? anyone ?
Click to expand...
 
The Castrol bottle has an extendable nozzle, which is slim enough to fit right inside the diff fill hole. So I just placed the nozzle in the hole, then pushed the bottle up between the half shaft and the suspension arm, and gave the bottle small squeezes. Not problematic at all. Each squeeze puts a gloop of oil in, and you can see an air bubble being pulled back into the bottle.
After the bottle was mostly empty I stuck a bit of wood between half shaft and bottle to tip it right up, and left it to fully drain into the diff.
With the second bottle, I had to stop just after I started.

Looking at the car, I think I maybe left some old oil in the diff, as the front of the car was very slightly lower. I thought I had the car exactly level, but if I did this again I would jack on the engine subframe to tilt the car back and forward a bit, and hopefully get absolutely all of the old oil out of the drain hole.
 
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