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School Me: TruTrac vs. G80 vs. Welded

jwernerny

New member
Joined
Aug 20, 2005
Location
Fairport, NY
I've had G80 diffs from the factory in 3 960s, my son's 940T, and (I think) in my 760 V6. I understand they lock between 5 and 30mph when there is wheel spin, and I LOVE driving
with them in that range on snow as I slide the tail around.

What is the practical difference between how the G80 behaves and feels vs. how a TruTrac does?

What about a welded (locked) diff?

Thanks,
-John
 
Can’t speak for trutrac, but welded is the most predictable and the most annoying IMO. The g80 sucks stock (for skids), but once modded it’s pretty predictable and fun. Just don’t blow it up. Modding it takes like 1 hr too.
 
true track is like a predictable g80. G80's, in my experience, do not always behave as advertised. Sometimes they lock up right away, sometimes they wait, sometimes they lock up at a much higher speed than intended, sometimes they never lock up.
welded is annoying. not bad for drag racing or otherwise sliding around and that sort of ****, but it has an impact on how the car handles (esp at very low speeds). Having now driven a decent hp car with a true track, I think that it's money well spent, and someone oughta offer a good tone ring option ;)
 
I think how good the oil is in your G80 might be the reason the G80 has acted strangely for some folks. I have one that I plan on putting in my 93 wagon so I guess I will experience that first hand.

That said, I had a true track installed in my 82 turbo and it's been an excellent upgrade. I now have 90k miles on it and since it's a no preload version it has taken some wear but still functions. I hear noises now that probably wouldn't happen if it was a preloaded version. It's one of my favorite upgrades to the turbo.

We used to use a welded diff on my brother austin healey sprite race car. Great in that application. I wouldn't use a welded diff on the street.
 
Yeah the thing about the oil in the G80 is do not put any oil in it that has the LSD oil or additive in it. Straight GL-5 oil is what GM says to use. That is just full synthetic no friction modifiers gear oil. No friction modifiers need in your g80 unless you want it to not work.. It has plates like a normal LSD, but they are metal so the frictions modifiers make them not lock like they need to.

If the car still drives but the g80 doesn't lock it's usually that little ramp up gear on the counter weight rod that has stripped it's teeth and it then can not ramp up the plates into locking.
 
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Eaton makes an e-locker for the Dana 30 too. I've considered it in a winter car for the purposes of ultimate traction in the snow (Sloppy trailheads in the winter), but I'll probably end up getting a Trutrac for all around winter DD purposes.

Then there's also the Auburn Gear ECTED which is a combination of clutch type limited slip and selectable e-locker. $880, I wonder if it really fits in a 1031...
 
I believe the Quaife has a lower torque bias ratio when compared to the rear Trutrac.

Please explain what that means to me. Thanks very much.

I believe Quaife is big into racing so maybe their differential would be good in a track car.
 
I just bought the wavetrac one from trianglesunlimited.com. Hopefully will be getting installed by next month. It's supposed to be epic?
 
Also very curious about the wavetrac, I was considering one but the reviews are mixed, some people love them, others have had catastrophic failure. For the price it seems a gamble, but who knows.
 
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