Gear oil - GL-4 & LSD

[AvivB]

Hi everyone,

I'm adding Cusco LSD to my FWD gearbox and I'm looking for a gear oil that will play nice both with the gear synchros and the LSD.
From previous experience I know the GL-5 oils (or at least 4 out of 4 I tested) didn't play nice.
But now I cannot find a good gear oil which is both GL-4 and contain the extra ingredients for LSD.
Any recommendations?

 

[underscore]

Could you use GL-4 plus an additive for the LSD? I know Chrysler makes an additive for the clutch packs in my Jeep diffs so I assume there are aftermarket options.

 

[93celicaconv]

Some have used a Red-Line product that they say works good with combination manual trannys w/synchro's and with hypoid gears. Otherwise, Toyota used to carry GL-5 Gear Oil Super (08885-02106), which was originally put into ST165's & 185's for hypoid & synchromesh transmissions - sold in 1 liter cans (at about $20/liter).

 

[sefiroxx]

Been running redline mt-90 for years with never a clunk and smooth sailing on my FwD.

Can't speak to the LSD impact though

 

[Magroo]

I've been using red line 75w90ns. A lot of subaru guys use the same and throw a bottle of red line lightweight shockproof and a bottle of synthetic gear lube for lsd.

Obviously the best choice is going to be the oem gl5 super but its expensive as frick. I think around $40 per quart.

 

[Menoxz]

Hi everyone,

I'm adding Cusco LSD to my FWD gearbox and I'm looking for a gear oil that will play nice both with the gear synchros and the LSD.
From previous experience I know the GL-5 oils (or at least 4 out of 4 I tested) didn't play nice.
But now I cannot find a good gear oil which is both GL-4 and contain the extra ingredients for LSD.
Any recommendations?

Hello. Holy revival here
In the GT4 transmission where the transaxle needs Gl-5 and the gearbox need GL-4,
Castrol Syntrax 75-90w is both GL4 and GL5 compliant. Works for me and removed synchro issues

 

[AvivB]

Hi everyone,

I'm adding Cusco LSD to my FWD gearbox and I'm looking for a gear oil that will play nice both with the gear synchros and the LSD.
From previous experience I know the GL-5 oils (or at least 4 out of 4 I tested) didn't play nice.
But now I cannot find a good gear oil which is both GL-4 and contain the extra ingredients for LSD.
Any recommendations?

Hello. Holy revival here
In the GT4 transmission where the transaxle needs Gl-5 and the gearbox need GL-4,
Castrol Syntrax 75-90w is both GL4 and GL5 compliant. Works for me and removed synchro issues

Castril Syntrax is s series, but I guess you refer to "Castrol Syntrax Limited Slip 75W-90'.
From what I can see, this one is GL5.
https://msdspds.castrol.com/bpglis/Fusi ... bt523w.pdf

Are you referring to this one or something else?

 

[Menoxz]

Hi everyone,

I'm adding Cusco LSD to my FWD gearbox and I'm looking for a gear oil that will play nice both with the gear synchros and the LSD.
From previous experience I know the GL-5 oils (or at least 4 out of 4 I tested) didn't play nice.
But now I cannot find a good gear oil which is both GL-4 and contain the extra ingredients for LSD.
Any recommendations?

Hello. Holy revival here
In the GT4 transmission where the transaxle needs Gl-5 and the gearbox need GL-4,
Castrol Syntrax 75-90w is both GL4 and GL5 compliant. Works for me and removed synchro issues

Castril Syntrax is s series, but I guess you refer to "Castrol Syntrax Limited Slip 75W-90'.
From what I can see, this one is GL5.
https://msdspds.castrol.com/bpglis/Fusi ... bt523w.pdf


Are you referring to this one or something else?

Hello

This one is I'm referring to https://msdspds.castrol.com/bpglis/Fusi ... 9SXLHX.pdf

But looking at castrol site they might have changed it out the name to CASTROL TRANSMAX UNIVERSAL 75W-90 now, states it's GL-4 and GL-5 compliant

Either way I've been racing abit and the horrible crunch on third gear haven't happened at all since i've changed the oil. I've flushed the transmission from the old oil also.

I don't know if it will go acidic after years and attack brass synchros like regular GL-5 does, but it did wonders to my transmission

 

[AvivB]

Ok, I'll look into it.
Thanks.