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...It seams that some brands use more or less friction modifier in their formulation which may account for differences in the torque biasing applied by the Torsen.
This is not correct. The torque bias is based on mathematics, not oil, and can only be changed by replacing the gears in the spool itself. You might have chatter, but if you do that's damaging to the gears. I would drop that oil immediately and put in something that doesn't chatter. There should NEVER be chatter from a Torsen diff.
This is not correct. The torque bias is based on mathematics, not oil, and can only be changed by replacing the gears in the spool itself. You might have chatter, but if you do that's damaging to the gears. I would drop that oil immediately and put in something that doesn't chatter. There should NEVER be chatter from a Torsen diff.
I know that the shuddering was a common issue on mustangs that used the Torsen, so much so that Ford started
using a friction modifier additive to eliminate the issue.
Even Torsen on their website has stated that using different fluids with or without friction modifier will affect the torque biasing
on their units, they also state that the shuddering does not affect the longevity of the unit...
I am certainly not an expert in the matter and only repeating what Torsen states:
Typically, heavier oil weights provide better protection since they leave a heaver film of oil on parts. This provides better lubrication, it also can provide better shock protection. It is worth noting, however, that the heavier the oil film is, the more it will reduce locking effect (or torque bias ratio) of the differential. Essentially, anything that reduces friction in the diff reduces its locking characteristic. Between 75W90 and 75W140, you probably won’t know the difference. But in applications (like FWD cars) that run in ATF, the difference is notable. Also, heavier weight oils typically absorb and handle high heat better before breaking down. With all of that in mind, I would personally use the 75W140.
With regards to friction modifier, it is there for NVH reasons. Limited slip differentials – even helical gear designs like Torsen – can make assorted noises in tight turns with low to moderate loads. Clutch diffs chatter, gear diffs squeak or moan. Modifier usually fixes these noises because it helps manage the frictional transition between static and dynamic modes. But in doing this, it does reduce the overall friction in the differential. As I said above, this has bearing on the differential’s performance as a result. In some cases, it can reduce the locking effect as much as 10%. For normal street cars, this is worth the tradeoff. For you, it may not be. However, you always have the option of adding modifier to the lube later on if needed.
Mike, you’re thinking if the old Posi units that also plagued jeeps for popping in low speed cornering.
i about choked when reading that quote from JTEKT. Initially I’m like sure, ATF versus gear oil is a HUGE viscosity difference. Pour some of each out and tell me you wouldn’t think it would alter some gear mesh characteristic. Got to digging on their site some...
>>>> No, TBR is determined by the design and geometry of the gearing. Once it is established for a given application, it is fixed for that model. It may be possible to affect very minor changes with different lubricants (+/- 0.1:1), which is not likely enough to be able to feel while driving.
>>>>
that’s a pretty darn small change and admittedly, you won’t notice it. Followed up with,
>>>>
Do I need to use friction modifier with Torsen?Yes and no. Although the differential does not use a clutch pack design, modifier additive is still sometimes used in OEM applications. In such cases, we suggest referring to the OEM recommendation.
Mike, you’re thinking if the old Posi units that also plagued jeeps for popping in low speed cornering.
i about choked when reading that quote from JTEKT. Initially I’m like sure, ATF versus gear oil is a HUGE viscosity difference. Pour some of each out and tell me you wouldn’t think it would alter some gear mesh characteristic. Got to digging on their site some...
>>>> No, TBR is determined by the design and geometry of the gearing. Once it is established for a given application, it is fixed for that model. It may be possible to affect very minor changes with different lubricants (+/- 0.1:1), which is not likely enough to be able to feel while driving.
>>>>
that’s a pretty darn small change and admittedly, you won’t notice it. Followed up with,
>>>>
Do I need to use friction modifier with Torsen?Yes and no. Although the differential does not use a clutch pack design, modifier additive is still sometimes used in OEM applications. In such cases, we suggest referring to the OEM recommendation.
Which brought me to my conclusion to revert to the OEM / Factory Filled supplied gear oil formulation as suggested by Torsen themselves .. These Torsen LSD units are Type 2
For what it's worth, I would avoid using gear oil type LT for the Torsen. Toyota has a special formulation that is to be used with Torsen LSD's, type LX. I mistakenly ran LT once in my Torsen and it was surprising how much chatter there was - almost like a clutch pack diff without friction modifier.
Generally Torsens do not need friction modifier, but I've found low viscosity oils can cause chatter, particularly the T2 units.
For what it's worth, I would avoid using gear oil type LT for the Torsen. Toyota has a special formulation that is to be used with Torsen LSD's, type LX. I mistakenly ran LT once in my Torsen and it was surprising how much chatter there was - almost like a clutch pack diff without friction modifier.
Generally Torsens do not need friction modifier, but I've found low viscosity oils can cause chatter, particularly the T2 units.
Diff looks great Joe!
Jeff
Thanks Jeff..!!! It was a nice pick up for sure..
Good catch on my typo.. I corrected my post #45 to the correct images & part number for the LX oil. Interesting to see how the TVD unit takes the LT and the Torsen unit takes the LX. Which is double the $$ cost of the LT oil..
I ordered TWO axles seals.. Seems they are LH & RH specific.. One had a slight tear.
I'm leaning towards the RC F differential bushings oem New. Different part numbers from the IS F.
The vertical design may have solved sloppy rear end shift or wheel hop.. ??
I may consider at a minimum to add the ear bushing SuperPro inserts only.. Still unsure. (learning)
The existing RC F units oem ear bushings are in great shape visually.
I know that the shuddering was a common issue on mustangs that used the Torsen, so much so that Ford started
using a friction modifier additive to eliminate the issue.
Even Torsen on their website has stated that using different fluids with or without friction modifier will affect the torque biasing
on their units, they also state that the shuddering does not affect the longevity of the unit...
I am certainly not an expert in the matter and only repeating what Torsen states:
Typically, heavier oil weights provide better protection since they leave a heaver film of oil on parts. This provides better lubrication, it also can provide better shock protection. It is worth noting, however, that the heavier the oil film is, the more it will reduce locking effect (or torque bias ratio) of the differential. Essentially, anything that reduces friction in the diff reduces its locking characteristic. Between 75W90 and 75W140, you probably won’t know the difference. But in applications (like FWD cars) that run in ATF, the difference is notable. Also, heavier weight oils typically absorb and handle high heat better before breaking down. With all of that in mind, I would personally use the 75W140.
With regards to friction modifier, it is there for NVH reasons. Limited slip differentials – even helical gear designs like Torsen – can make assorted noises in tight turns with low to moderate loads. Clutch diffs chatter, gear diffs squeak or moan. Modifier usually fixes these noises because it helps manage the frictional transition between static and dynamic modes. But in doing this, it does reduce the overall friction in the differential. As I said above, this has bearing on the differential’s performance as a result. In some cases, it can reduce the locking effect as much as 10%. For normal street cars, this is worth the tradeoff. For you, it may not be. However, you always have the option of adding modifier to the lube later on if needed.
I hope this helps.
JTEKT Torsen North America, Inc.
This does not reflect my experience with the Torsen diff in my Supra. I've run everything from Red Line NS with friction modifier added a little at at time, to full slip GL-5 gear oil which said "DO NOT USE IN MANUAL TRANSMISSIONS" on the bottle. None of it made any difference at all, and this spool has never once in 160k miles of running made any unusual noise from the diff. Plenty of other stuff has, but not the diff.
Started this project to swap the diffs by myself this weekend and it's a good learning experience...
Haven't undertaken a mechanical moderate job like this in over 20 years..
Everthing has been going accordingly to plan, but unfortunately don't have the right tools to pop the axles.. Haven't even gotten to the more difficult diff mount remove and reinstalling the new versions found on the RC F.
Working on the floor is never easy, and doing it alone is never fun..
Pausing for the day while I revaluate next steps..
Semi win was the removal of the old axle seals (one was damaged by salvage yard) and carefully tapping in the new ones into the RC F Torsen unit.
Doesn't look as clean or smooth as I would have liked, but it should work fine. Feels even all around and yes they are LH & RH specific seals. Thanks for the tips @lobuxracer
Quick Facts: Removing the rear undercover under the spare tire compartment opens up a lot more bonus room.
Also removing the Rear Sway bar with end links was easy.
Edit New Tip:
If you don't have the right tools to remove the axle seals or install them.. You can use the old ones to assist in tapping in more cleanly & evenly...
Should be safer to whack away at the old seal, on top of the new seal.
In all my searching, it seems no one has "yet" attempted a Torsen LSD swap into a RWD LS460 (2007). Fellow gearheads, is there "Any" Lexus pumpkin with a Torsen LSD (2.93) that would swap into my 2007 LS460 RWD (2.93)? Greatly appreciate the feedback!
Well finally found the time to wrap up this project today.. Basically my F remained as was for almost 4 months.
Special thanks to the team over at Haas Bros Auto in San Dimas.
ASE Master, Hybrid Certified, Toyota Master Dignostic Tech & Master Tech.
This was the same shop that replaced my starter few years back when I was in a pinch.
The work took approx. 3-4 hours from start to finish with some creativity in between..
Popping the axles went as planned with a two man team. One person lined up the axle with a long pry bar. The other used another short pry bar and mallot to whack them / unlock the clip.. I also opted to have them install the new oem RC F diff mounts. Those took some effort but worked better then expected when he found an old bearing the same exact size to whack on, to get the old ones out of the subframe.
I also picked up the SuperPro pinion ears bushing insert kit and those went on as well
as 17mm SuperPro sway bar bushings. Part numbers below.
SPF3494-17k Rear Sway Bar Bushing SPF2769k Rear Differential Pinion Bushing
See my post #54 in this thread for any other OEM part numbers used for the swap.
My question is why all that work to install oem rcf bushings when you could have done superpro bushings for those as well. Why only for the arms on the diff?
05-03-20, 05:08 PM
Raising the white flag...
