Rear Differential Oil

[Wrenchbender Ret]

The GL 5 is not the viscosity. It is a anti friction rating. You must use gl5 in differentials.
Practically all gear lubes are rated for GL 5. If your seals are old you might use 85w140 in the rear end unless you are using it in extreme cold.
If it is a Posi-trac you need to put an additive in it.
George

[ManNamedJed]

I put 'Lubelocker' gaskets on mine. No sealant needed and you can reuse them if you have to pull the cover again. No leaks ever.

[CS1972]

I used LubeLocker for both my front Dana 44 and the rear 12 bolt and NO LEAKS ! Quite honestly it's my first time not using the typical gasket / sealer and after doing so I don't know why anyone would mess with smearing it all on equally and dealing with the mess. Sure the Lubelockers are more, but remember you don't have to buy the sealer.

Take pics of your ring gear so you'll know what ratio you have FOR SURE.

I used Mobil1 75W-90 Synthetic Gear Lubricant LS which will work for BOTH limited slip and non limited slip rear ends.

[53burb]

I used the Right Stuff by Permatex on my rear diff on my Ram....no gasket...worked great!!
I learned about it from this site....surprised no one has mentioned it yet....

https://www.amazon.com/Permatex-3369...a-448741432246

[57taskforce]

Originally Posted by 53burb

I used the Right Stuff by Permatex on my rear diff on my Ram....no gasket...worked great!!
I learned about it from this site....surprised no one has mentioned it yet....

https://www.amazon.com/Permatex-3369...a-448741432246

Same here I get the big aerosol can of the right stuff for jobs like this. Never had a leak using it and it cleans up pretty easily when it’s time to change the oil again. In use 80w90 for oil.

[Bigdav160]

Originally Posted by Wrenchbender Ret

The GL 5 is not the viscosity. It is a anti friction rating. You must use gl5 in differentials.
Practically all gear lubes are rated for GL 5. If your seals are old you might use 85w140 in the rear end unless you are using it in extreme cold.
If it is a Posi-trac you need to put an additive in it.
George

Just for clarity, GL5 is a SAE test sequence that certifies a fluid to meet a standard.
It is normal for an older standard be replaced by a newer standard.

But there is nothing to prevent an oil blender from marketing an lubricant without pursuing the expense of certification.