by "Censored" (chrisbrown2992)
Published 01/26/2017 at 21:10
by "Censored" (chrisbrown2992)
Published 01/26/2017 at 21:10
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STARS: 4
Inspied by a post conversation earlier about a gm truck pulling a semi I felt compelled to show yall something that you may or may not have seen before. Thats the innards of an Eaton G80 rear diff. It is an automatic “locking” rear diff. I put locking in quotes because purists will argue that it isn’t a true locker if you don’t have control of it. I somewhat agree with the sentiment, but the g80 is a fantastic rear end.
It works by having a flywheel in between the two axles that has pivoting weights on it. Once the two axles reach a 200rpm difference the weights fly up and lock the two axles together. The axles will stay locked until the load on the rearend is removed. This gives you the benefit of a locker and an open diff automatically. No lsd clutches to wear out or air lockers requiring onboard air.
Have some vids.
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That last video appears to be a 2wd truck. There are no 4x4 stickers on the back and the front tires don’t spin on the start.
Down sides are complexity and their tendencies to explode if you run much more than 33's and abuse it.
All and all the G80 is a pretty awesome diff in a stock/slightly modified truck. I have 160k on mine and it has never let me down. Now to find some wood to knock on.
Hope you enjoyed my first post or more appropriately, ramblings.
"shop-teacher" (shop-teacher)
01/26/2017 at 22:51, STARS: 1
I thought G80 was just a GM option code for a locking differential. I learned something today. I have one of these in my 2wd Sierra.
"crowmolly" (crowmolly)
01/26/2017 at 22:58, STARS: 1
It is. Depends on year and application, but truck people use the term for their locking diff.
Kind of like how every Gen III swap is an “LS swap” even if it’s an iron blocked truck engine.
Gov Lock is a good street diff, but it’s Achilles heel (from what I recall) is when it locks up too fast under load on pavement.
"shop-teacher" (shop-teacher)
01/26/2017 at 23:01, STARS: 0
Gotcha. Mine has served me well.
"Censored" (chrisbrown2992)
01/27/2017 at 09:34, STARS: 1
G80 is also the GM RPO code. I assume that since GM developed it with Eaton, Eaton just kept GM’s code as the name.
"Stephenson Valve Gear" (stephensonvalvegear)
01/27/2017 at 21:45, STARS: 0
My pickup has this locker, and I’m not a big fan. To be fair, it hasn’t had any problems (in just 37k miles of use), but the lockup at 200 RPM difference in axle speed can cause quite a bang or jolt. On a continuous surface of snow or ice, it’s no big deal, but where it is very noticeable (and it’s a situation where you need a locker) is with one wheel on clear pavement, and the other on ice or snow. I do my best to use some finesse in those situations, but during the winter it isn’t unusual to encounter a slick spot on one side or the other when accelerating or pulling. One wheel speeds up quickly, and BANG! IT’S LOCKED! I know it is a cheap option for a locking diff - especially compared to a gear type locker - but it can be brutal at times.
"Censored" (chrisbrown2992)
01/27/2017 at 22:00, STARS: 0
I agree 100% on the harsh engagement. However I’ll take that trade off for the performance it gives in a stock truck.
The first video actually states that engagement occurs at 100rpm difference, but everything I’ve heard/read in the past stated 200rpm. I can’t help but to think that engaging at 100 would help reduce engagement jolt. Just wonder what the rpm difference is at full lock.
"Stephenson Valve Gear" (stephensonvalvegear)
01/27/2017 at 22:42, STARS: 0
I agree, I do like having a locker in my pickup... even if it is a bit jarring. I gotta think that the 200 RPM figure is more accurate, as it seems like it the spinning tire has to attain a fair amount of speed before it locks. I’m kind of curious now... thinking of ways to test the lockup speed now...