Gbox oil

[Lincs Mav]

Ok I've searched the forum but can't really find the answer. What gearbox oil should be used in an R20 gearbox. Local car shop has it listed as EP 80/90 mineral GL5 reading up its saying don't use gl5. What should I be using please.

 

[solarman216]

Ok I've searched the forum but can't really find the answer. What gearbox oil should be used in an R20 gearbox. Local car shop has it listed as EP 80/90 mineral GL5 reading up its saying don't use gl5. What should I be using please.

GL4 for the box, Rick

 

[Lincs Mav]

Cheers Rick so 80/90 mineral gl4 will be ok?

 

[firebobby]

As above, GL5 will eat your gearbox innards. MUST be GL4 :thumb2

 

[Lincs Mav]

Cheers chappies I've got some gl4 semi synthetic on the way

 

[firebobby]

Cheers chappies I've got some gl4 semi synthetic on the way

Top man :thumbs:thumbs

 

[glanrichbex]

After years of being told GL4 is the only oil that can be used -I have now this explained to me by an expert in transmission rebuilding.

The bearings in the gearbox are phosphor bronze and these bearings are self lubricating.

Phosphor bronze slowly absorbs oil ( that is why they are self lubricating ) but only oil of a specific type. If you use the wrong oil with a larger molecule ( not related to thicker oils ) then the pores in the structure of the metal will not absorb oil and therefore cannot contain oil and the bearing runs dry - even if the bearing is submerged in it!!.

GL5 will not be absorbed into the phosphor bronze and therefore the bearings will not be lubricated and disintegrate.

 

[Banshee]

After years of being told GL4 is the only oil that can be used -I have now this explained to me by an expert in transmission rebuilding.

The bearings in the gearbox are phosphor bronze and these bearings are self lubricating.

Phosphor bronze slowly absorbs oil ( that is why they are self lubricating ) but only oil of a specific type. If you use the wrong oil with a larger molecule ( not related to thicker oils ) then the pores in the structure of the metal will not absorb oil and therefore cannot contain oil and the bearing runs dry - even if the bearing is submerged in it!!.

GL5 will not be absorbed into the phosphor bronze and therefore the bearings will not be lubricated and disintegrate.

Boom!!!! :thumb2

 

[Gazza]

After years of being told GL4 is the only oil that can be used -I have now this explained to me by an expert in transmission rebuilding.

The bearings in the gearbox are phosphor bronze and these bearings are self lubricating.

Phosphor bronze slowly absorbs oil ( that is why they are self lubricating ) but only oil of a specific type. If you use the wrong oil with a larger molecule ( not related to thicker oils ) then the pores in the structure of the metal will not absorb oil and therefore cannot contain oil and the bearing runs dry - even if the bearing is submerged in it!!.

GL5 will not be absorbed into the phosphor bronze and therefore the bearings will not be lubricated and disintegrate.

Thats a good explanation but having recently stripped and rebuilt my gearbox I didn't notice any bronze bushes. The bearings on the shafts and gears were either ball, roller or needle roller. I thought the oil type may be due to the baulk rings which are made from brass (but I think they are brass in all gearboxes) The only other place bronze bushes may be fitted is in the shift forks where they slide along the rods.

 

[glanrichbex]

That's a good point about the bearings being roller or ball race - I do remember once stripping an outboard gearbox and one of the old bearings that came out was a full compliment roller bearing which fell apart on the bench. I picked up a magnet and they stayed on the bench????

I had a look to see if the rollers were stainless but they didn't look like stainless and wonder to this day if they are bronze.

 

[glanrichbex]

That's a good point about the bearings being roller or ball race - I do remember once stripping an outboard gearbox and one of the old bearings that came out was a full compliment needle roller bearing which fell apart on the bench. I picked up a magnet and they stayed on the bench????

I had a look to see if the needle rollers were stainless but they didn't look like stainless and wonder to this day if they are bronze.

 

[Gazza]

That's a good point about the bearings being roller or ball race - I do remember once stripping an outboard gearbox and one of the old bearings that came out was a full compliment needle roller bearing which fell apart on the bench. I picked up a magnet and they stayed on the bench????

I had a look to see if the needle rollers were stainless but they didn't look like stainless and wonder to this day if they are bronze.

Bronze is too soft for rollers or balls in a bearing. Ball & roller bearings are made from hardened chrome steel.