Synthetics = no good for LSD??

[metroplex]

whoah... and I thought figuring out whether the 98-up E-250 has a Dana 60 or a Dana 44 in the rear end was hard!!!

I'm getting a lot of conflicting info from one or another.

Zexel is saying that most of their customers prefer Redline and they're fine with that.

TracTech states that the synthetic hurts torque bias performance.

 

[Mike_dup1]

does that tractech have a web site? never mind found with google

[ January 14, 2003, 12:49 PM: Message edited by: Mike ]

 

[metroplex]

That's a pic of what's going in the Vic. Notice that its slightly different from the Torsen T-2 (namely the helical gear design). The T-2 has an empty part in the middle of the helical gear...

I was told the TrueTrac will not break with taller tires where the T-2 will just grenade itself... so the TT is a hair stronger than the T-2. So far the general consensus was to NOT drag race with the Torsen style differentials!!! A few stang owners grenaded their TT's one after another using 7000 RPM clutch dumps w/ Nitto drag radials.

[ January 31, 2003, 02:28 PM: Message edited by: BOBISTHEOILGUY ]

 

[OneQuartLow]

Whatever Eaton's reasoning for their clutches, that would be different.

Metro, if it were mine I'd email redline and ask their perspective. If the warranty is important to you then do what's required. At least run a quick batch or two of conventional to clean out the new metal.

140 should hold up better but will also run hotter. How often are you really racing/towing? As for the 8.8, if that unit is is similar to the solid models you might want to upgrade the cover. One 8.8 weakness is the tendency of their housings to deform under shock loads which leads to bearing failure. Plenty of aftermarket covers available.

I can only speculate how the Torsen gears will respond to different weights. It'd be an interesting experiment.

There's a special freedom to selectables & welded spiders.

 

[OneQuartLow]

Metro, are you sure your version doesn't have 3 side gears? I thought the 2-gear version was old and had heard of several of them failing, both offroad and on with larger tires.

 

[metroplex]

Yeah I really like this Vic.

I'm not designing it to outrun Camaros or Stangs, but its a full sized RWD sedan - not a FWD Import that fits in a lady's purse.

It's got about 230 hp and around 290 lb-ft of torque. From the day I took delivery of this car, I wanted posi. I was so disheartened to see "3.55/non-locker" on the window sticker. I asked if I could order the Traction-Lok (Ford LSD) but the guy said only cop cars got them.

I'll see if I can get the cover for less $$ somewhere... sounds like a good idea tho.

 

[1 FMF]

I've emailed Torsen directly about what fluid is required in the rear end with their differential.

I emailed them because the owner's manual specified GM syn. gear lube with friction modifier added. But I've heard friction modifier isn't required, so I had to do some research to be sure I was using the right gear oil. In short, any weight oil is okay but it has to be GL-5 type gear oil. It needs to be GL-5 because of the ring and pinion gear needs. Friction modifier or limited-slip additive is not required. It is recommended though because the torsen differential is noisy in low speed tight radius turns, and friction modifer elimates the noise but sacrifices performance a little bit. The noise is just characteristic, no damage is being done. So going off that logic, the torsen needs a certain amount of friction to operate properly. Adding too much additive, or a synthetic fluid that's too slippery, will cause the differential not to lock up as intended. This isn't hurting the differential in any way, you're just not getting full lock-up from it. The solution would be to use an oil with no friction modifier and put up with any low speed noise as a result. It's a big trade off, either slippery synthetic fluids with reduce friction, heat, and parasitic loss or more frictional conventional gear oils with higher heat and more parasitic loss but better differential lockup. I personally use redline 75w90 with the slip additive in it. I might try the 75w90NS in the future. One way to go might be redline 75w90NS, has no additive but all the benefits of a "synthetic" lube? And you can always add friction modifier in small amounts to get desired effects.

currently 2002 Camaro SS owner
past 1999 Camaro SS owner that I destroyed the rear on by shearing the pinion gear shaft, gear defect that was totally oil unrelated.

[ January 31, 2003, 02:25 PM: Message edited by: BOBISTHEOILGUY ]

 

[metroplex]

Hey thanks! I wanted to ask Camaro owners directly but could never find the major forums.

My 2000 Ford Crown VIc now has a Detroit trueTrac (same idea as a Zexel Torsen T-2).

I'm using Valvoline Synpower to help break in the differential - then I'm switching to Redline 75W-90.

The 75W-90NS seems to be a tad thin at lower temperatures - the 75W-90 looks like a better solution.

Regardless with a Torsen, you will not get 100% lockup regardless of what fluid you use. I believe this is the nature of the beast. If one wheel completely looses traction, you must apply the brakes in order to apply torque to that free wheel, so the torque biasing can do its thing with the gripping wheel.

Just out of curiosity, do you hear any noises in tight turns?

my TrueTrac was noisy for the first 1-2 miles but soon after it was extremely quiet.

 

[Mike_dup1]

Cut this right from the TORSEN SITE

quote:

---

Can Torsen recommend an oil for my rear axle?

We suggest that you follow what is listed in your vehicle's owners manual. We do require that a GL4/GL5 class oil be used for the Torsen T-1. The T-1 requires an oil with extreme pressure additives for optimal function. Torsen works well in either synthetic or mineral base oils!

Torsen for Ford Vehicles:

Which Torsen is in the Ranger FX4 - Level 2?

The Ranger FX4 Level 2 comes standard equipped with a pre-loaded Torsen T-2.

Torsen for GM vehicles:

Is it true that the Torsen unit in the production Camaro needs the GM modifier added?

GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.

---

 

[S2000driver]

The S2000 has a T-2 LSD. Owners are amazed at how dirty the fluid is by 6000 miles. The common practice is to use Mobil-1 (synthetic) 75W90 GL-5 at the first change. Then at 15,000 more miles, the fluid comes out relatively clean.

Maybe synthetics potentially reduce the amount of limited slip torque transfer.

But it's working well for our Honda S2000 community.

 

[metroplex]

I think there are only 4 ppl (me included) in the Ford Panther community that have Detroit TrueTrac differentials. (The Torsen T-2 isn't available for the Ford 8.8" w/ 28 spline axles only 31 spline axles).

So far the other 3 have gotten real mileage with their differentials - they did not report any abnormal fluid conditions (excess metal shavings, dirty fluid, etc) and they all use a variety of synthetic gear oils.

I'm already sold on the use of synthetics. And from what I've felt, the truetrac w/ synthetics is actually a bit more responsive than a Dana 60 w/ Traction-Lok (clutch) using dino SAE 90.

 

[Scott P]

I don't mean to bring this topic back from the dead, bt a co-worker and I were talking about his 86 monte SS and he was thinking about getting some synthetic (Amsoil) fluid for his factory limited slip differential.

It's been over 12 years since I last touched a GM 7.5 inch limited slip. Is a synthetic a good choice for this rear end?

 

[Ken2]

Good choice, as long as it's the correct synthetic and meets all the requirements for the lube...GL-5 and whatever else the manufacturer of the gears requires.


Ken

 

[Scott P]

Thanks for the reply. I'll be passing that information along to him.

 

[Jimbo]

I had a '94 C1500 with the factory GM LS unit and it did not like synthetic fluid. It would chatter and the pinion seal suddenly started to seep. The truck had less than 40,000 miles and was leak-free before. I do not beleve those that say syntetic oils do not cause leaks. A slightly worn seal may not work perfectly with synthetics.

The GM LS uses a bronze cone clutch, unlike the disc clutches on a Ford or Dana unit. The bottle of Valvolne Syn-Power said that it was ok for limited slip. I switched over to the Durablend product and the problem disappeared. I now know that GM makes an excellent friction modifier additive for LS units.

Synthetic is now factory fill for these units, but I don't know which one GM uses and if they still use their own additive, which they probably do.

 

[metroplex]

I found Valvoline Synpower to be sub-par as a gear oil. It foams like mad, when I cracked open the rear end cover on my Ford 7.5", the oil had air bubbles up the wazoo.

Pennzoil Synthetic 75w-90 did not have air bubbles when I drained it.

 

[higney85]

i have a detroit truetrack and i run mobil 1 synthetic in it and it locks up great....

 

[metroplex]

What model TrueTrac do you have (which vehicle is it for)?

And what are you using it in, front or rear (if you have a 4x4)?