diff oil specs??? oil question

C

craigfitzgerald

Member
hi there i was wondering if you can use gl5 80/90 in the rear diif.
i read some where a while back that you can only use gl4 80/90 the problem is i cant remember where. i was wondering if the reason for that was if the oil and original seals are incompatible?? or is the diff sensitive to the oil type used??

i am just wanting to know as i am about to refit my diff back to the car and was wanting to use the correct oil, after replacing the 5 seals.

thank in advance
craig
 
Hi Craig,

Yes, you can use GL5 80W90 without any compatibility problems.

Just ensure that the car is on level ground when you refill. If oil flows from the filler plug hole, allow it to cease flowing prior to refitting the plug.

Ron.
 
Does your differential have a breather on it. Early diffs did not, and as a result tended to have leakage problems. You can buy a kit from Wadhams to install a breather.

GL5 will be fine. GL5 can be a problem in gearboxes with yellow metal synchromesh. Some GL5's corrode the synchro rings. Consequently GL4 is specified instead, and is hard to find.

James.
 
Joop said:
Hello

Could anybody explain me wy there should be a breather on a differentiel?
Click to expand...

Because without one (or if the breather is blocked) the diff will leak because of the build up of pressure inside.
 
yup, an issue on Midget rear axles; diff heats up & oil expands, everything gets toasty and if the breather's blocked it forves it out of the hub seals and onto the rear drums...
 
craigfitzgerald said:
hi there i was wondering if you can use gl5 80/90 in the rear diif.
i read some where a while back that you can only use gl4 80/90 the problem is i cant remember where. i was wondering if the reason for that was if the oil and original seals are incompatible?? or is the diff sensitive to the oil type used??

i am just wanting to know as i am about to refit my diff back to the car and was wanting to use the correct oil, after replacing the 5 seals.

thank in advance
craig
Click to expand...

HI Craig, I'm confused too, there seems to be so many conflicting opinions on line.
Like you i have just replaced the outer oil seals and bearings but i am concerned that i have around 3mm rotational play on the out-put shafts and can hear a rattle noise when turning the drive shafts back and forth?
What oil did use end up using?
Regards
Dave
 
iwish wrote,...
i have just replaced the outer oil seals and bearings but i am concerned that i have around 3mm rotational play on the out-put shafts and can hear a rattle noise when turning the drive shafts back and forth?
What oil did use end up using?
Click to expand...

Hi Dave,

What you describe is the backlash between the gears, and that is completely normal. Use either a straight EP90 or an 80W90 gear oil.

The differential in my Rover behaves in exactly the same way, now with over 330,000 Miles (531,000km) and still going strong!

Ron.
 
SydneyRoverP6B said:
iwish wrote,...
i have just replaced the outer oil seals and bearings but i am concerned that i have around 3mm rotational play on the out-put shafts and can hear a rattle noise when turning the drive shafts back and forth?
What oil did use end up using?
Click to expand...

Hi Dave,

What you describe is the backlash between the gears, and that is completely normal. Use either a straight EP90 or an 80W90 gear oil.

The differential in my Rover behaves in exactly the same way, now with over 330,000 Miles (531,000km) and still going strong!

Ron.
Click to expand...

Thanks Ron,
That's just what i wanted to hear. :D
Dave
 
There are general concerns about gear oils degrading brass & bronze parts inside the gearbox or diff. This is more a problem with gearboxes and synchro rings that diffs, though. It has to do with the additives pack in the oil. GL4 is better in this regard than GL5.

Yours
Vern
 
Vern Klukas said:
There are general concerns about gear oils degrading brass & bronze parts inside the gearbox or diff. This is more a problem with gearboxes and synchro rings that diffs, though. It has to do with the additives pack in the oil. GL4 is better in this regard than GL5.

Yours
Vern
Click to expand...

For the Diff and eventually Power Steering Box I'm tempted to use the GL5 as its more readily available and i assume more developed?

As I'm not planning to dismantle the diff, does anyone know if there are any bronze or brass parts inside?

I assume the Alloy extension piece is OK?

Regards
Dave
 
iwish said:
Vern Klukas said:
There are general concerns about gear oils degrading brass & bronze parts inside the gearbox or diff. This is more a problem with gearboxes and synchro rings that diffs, though. It has to do with the additives pack in the oil. GL4 is better in this regard than GL5.

Yours
Vern
Click to expand...

For the Diff and eventually Power Steering Box I'm tempted to use the GL5 as its more readily available and i assume more developed?

As I'm not planning to dismantle the diff, does anyone know if there are any bronze or brass parts inside?

I assume the Alloy extension piece is OK?

Regards
Dave
Click to expand...

I wouldn't call it more developed, as in better. Just different. I think the only yellow metal in the diff are the thrust washers for the side gears as the spider gears thrusts are steel. Aluminum isn't affected. I don't think GL5 will be problem. Hope not anyway, as it's what I've been using for some time. As I mentioned earlier, it's gearboxes that are the primary concern.

Yours
Vern
 
harveyp6 said:
iwish said:
Vern Klukas said:
For the Diff and eventually Power Steering Box I'm tempted to use the GL5 as its more readily available and i assume more developed?
Click to expand...
Click to expand...

The Power assisted steering uses ATF, it's the manual box that uses EP90.
Click to expand...

Good job you corrected me on this, i got completely mixed up as the car is currently manual steering and i have bought the bits for a power steering conversion as part of my restoration. :oops:
 
Hmm I really should check the oil in my box and diff considering I have been driving it about with 30 year old oil!
 
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