G80 Locker Mod

[DeathWagon]

Soo I installed a locker from a 91 740 turbo in my car a few weeks back. I was happy with the way it worked accept for the fact that it wouldent lockup much past 20 mph. Well as yall know i enjoy the high speed drift every once and a while so this lockers performance just wouldent do. I found there is a speed governor that keeps the locker from engageing above 20mph soo all i have to do is mod that. There is a weight inside the carrier that is about 1 1/2 long and about 1 1/2 inches wide. It slings out past 20 mph and keeps the locker from activating. I busted out the grinder and decided to reduce the weight so it would swing out at a higher speed. The real trick is to keep all the particles out of the rest of the diff or it might wear out very quickly. Also I had to use a grinder with carbon disks because the weight is HARDEND Steel. I removed about 15-20 percent of it and tried to remove the weight as far away from the pivot as possiable so the removed weight would be more affective.

The result was a locker that will lock up till about 50mph now and alows for full fun drifting and higher exit speeds out of the corner.

I will try to find some pics to describe this better but for a really good video on how the locker works go to eaton's website and chekc out the link for the G80 locker. http://www.traction.eaton.com/prod2.htm

Here is a pic of the weight you want to lighten


Enjoy
Sam Collier

[thelostartof]

great write up .. want me to cut and resize and host that pic for ya?


also just kind of my experiance w/ this locker(as its stock in my 91') that i've found once it engages it will stay engaged till i let off the gas @ least on my car. also from higher speeds if i break traction its always both tires spinning ... so yea mine might be one of those odd balls but for some reason mine will always lock when one starts to spin as i've never had this car just spin one wheel always both

http://www.hardcars.com/thepriestmike/g80mod.jpg

[volvo9]

Nice mod, I was just thinking of something like that the other day.

That's normal operation BTW, once it locks, it stays locked till you let off the gas.

Oh, and the cutoff wheel on the grinder must have made one hella mess, how did you clean it up when you where done?

[Chigga 744SE]

great idea, I've always hated mine when comes to auto-x and drifting events, I alway spin the inside wheel when on gas and its awfully embarassing, people go "you spun both wheels off the line, how come only one spun at that corner?", I just go "ugh....... the locker is gay.

[thelostartof]

how is it that my locker doesn't act like anyone elses in the way that around corners @ higher speeds mine will always be locked .... i have never had an issue w/ just one tire spining its always both on mine(makes for some interesting times)

[Matt Dupuis]

Bumpsy-daisy.

I just picked up a locker of my own and after having a look at it, I came to the same conclusion Sam did. Decided I'd do a write up on it, but I'd better have a look first... found this.

I'll take some pix today and tomorrow & add them to this thread.

[Dfer10]

sweet sounds good Matt

Originally Posted by Matt Dupuis

Bumpsy-daisy.

I just picked up a locker of my own and after having a look at it, I came to the same conclusion Sam did. Decided I'd do a write up on it, but I'd better have a look first... found this.

I'll take some pix today and tomorrow & add them to this thread.

Matt, please do... I'd like to see the pics.

Mike

[boostdemon]

... and then submit it! looks good guys

[Matt Dupuis]

Got it apart and clean last night - I'm at work right now so no pix yet. Pretty simple in operation, and should be cake to modify properly but you'll have to go a bit further than just pulling the inspection cover and let the sparks fly.

One thing I'm a bit worried about is getting the cross pin aligned properly. It's an interference fit and takes quite a bit of force to get moving. I don't have a press, so I'm thinking that I'll have to heat up the case and chill the pin and work quickly! Fortunately this step isn't mandatory for anyone wanting to modify their locker - I just wanted to fully inspect mine and make sure it was clean - the oil in this unit was DREADFUL.

More work on it tonight, and pix soon.

[Matt Dupuis]

I think it's pretty obvious to state that by doing this mod, you must have faith in your skills, your tools, and that this is what you want to do. It's un-reversable, and by screwing up at any stage, you can cause eventual failure to your differential unit.

This doesn't just mean that the locker won't lock - this could mean that the bearings will disintegrate, seizing your differential suddenly and unexpectedly (though with PLENTY of aural warning), sending you spinning into the nearest ditch. Ask me how I know!

Also, this locker is designed to unlock above 25 MPH so that you may be safer. If you're on a highway and one wheel starts to spin, you keep going straight. If the locker kicks in and both spin, you can spin into the nearest ditch. Again, ask me how I know.

By modifying your locker, you give up this safety feature in the name of increased performance and dorifto ackshun. You asked for it.

Here's the filthy chunk. Remove the bearing caps after marking their location and orientation for later installation.



Undo the bolts holding the axle end plates in place.



Pull the axles out a few inches - it might be necessary to whack on them a bit to break them loose.



There are two major components to the actuation of this locker. The flyweights (screwdriver, holding them apart) and the governor pawl (to the right).



At low speeds (below 25 MPH) the governor pawl sits in this position, held by a torsion spring:



And at higher speeds, centrifugal force on the big counterweight overcomes the spring and it sits like this. Remember this for later...



Getcher tin snips and cut thru the oil slinger/bolt retainer thingie - no other diff has this so it must be a Volvo thing - I'm sure it has a purpose, but meh.



Mark the position of the ring gear relative to the differential housing, and remove the gear.



There are three T27 Torx screws holding the case to the ring side plate. Remove these, and tap the plate off the case. They only go back together one way and it's pretty easy to see, so no marking is necessary.



Voila! A mess!

[Matt Dupuis]

Here's the mechanism as it sits when it's assembled. There are a few pieces missing, like the caps that capture the clutch ears, but that's not important now. It's plain to see that the flyweight shaft is geared to the ramp, which is driven by the side gear. When one wheel is spinning, either the case will turn faster than this side gear or this side gear will turn faster than the case, depending on which wheel is spinning.



When the flyweight spread, one of them will hook onto the governor pawl and stop the shaft from turning.



When the side gear and ramp are in the neutral position, they look like this:



But when the flyweight shaft stops the ramp and the side gear rotates a little bit more, the ramp is forced by the matching ramps on the side gear into the clutch pack, which locks the differential.



Again, at low speed, this is how the governor pawl sits, with the spring pulling the hooks into the flyweight shaft.



And at higher speeds, the governor pawl counterweight overcomes the spring, pulling the hooks away from the flyweights, which just lets the flyweights spin. This keeps the differential open above 25 MPH.

[Matt Dupuis]

Here's the governor pawl. You can see by the general shape that the hooks are oriented to catch the flyweights in either direction. The counterweight is massive enough to overcome just about any spring, so don't bother trying to modify the spring here...



Using a thin carbon cut-off blade on my angle grinder, I just whacked the entire thing off. If you're not afraid of experimenting and you want to keep SOME function to the governor, you could hack off some of the weight, reassemble, see where it stops locking, and do it over and over until you got it right.

So after reading that, yours probably looks like mine does. You probably were also amazed at how much gear oil this hardened steel lump "sweat"...



After clipping the governor and spring onto the shaft, reinsert the pawl like you see it here:



And then, pushing the pawl in while holding the spring out, insert the flyweights.



Note the orientation of the weight and spring, in this and earlier pictures.



Reassembly of the ring side plate starts with replacing the shim,



reassembling the side gear clutch packs,



and inserting them into the side plate. Make sure the ramp and side gear are in "neutral" and that you remembered the clips that capture the clutch ears.



After you slip the governor and flyweight shafts into the side plate, the assembly slips together. Using a few of the differential bolts to line the cases up, insert the T27 machine screws and work your way around the case a few times, pulling it all together. The diff bolts hold the whole thing together, so don't worry too much about these machine screws - they only hold it during assembly.



Bolt the ring gear on, using the marks you made earlier to line them up, and you're done. Make sure you have a manual to provide you the proper torque settings and tightening sequence for the ring gear bolts and the bearing end caps in the differential housing. I didn't have the manual, so I used my calibrated impact wrench, in a modified star pattern, working my way slowly and evenly around the case.



Fin.

crikey... when you say "pic later" you really mean it!

now by just removing and reinstalling as is, as long as you don't much up the shims, you don't have to realign this right?

thanks for the pics Matt... I know what I'll be doing this weekend.

Mike

[Matt Dupuis]

Now, how does one submit it?

Edit - never mind.

[RoadRacer4Life]

Matt
Awsome job man that looks great. How well does it work ? I only too some material off of the counter weight but I wish I had taken the whole thing off like you did. Anyways what a great addition to my old thread and I hope it works well for ya..

Sam

[coldfusion21]

matt, your a god


that is all.

[Matt Dupuis]

Originally Posted by RoadRacer4Life

Matt
Awsome job man that looks great. How well does it work ? I only too some material off of the counter weight but I wish I had taken the whole thing off like you did. Anyways what a great addition to my old thread and I hope it works well for ya..

Sam

I'll be bolting it in this weekend, so I'll let ya know. It's a non-turbo automatic so I won't find out the traction benefits until it snows, however...

[Spottty]

Awsome write up man. I have a line on a stock locker and it looks like i'm going to do some modding before it goes in.

[Tha VZA]

Originally Posted by coldfusion21

matt, your a god


that is all.

no shat...sounded way simple'er on the phone...jeebus Matt...

i have a long way to go before i am "confident" in myself to take this project on by myself...

ciao

[volvorsport]

can one just weld the flywheel weights to keep it shut ?

looks like ill be doing something like that in the future !!!

i need to hear how it works , will you re align the CWP , before its put back in ?

[Matt Dupuis]

So far it's totally seamless, David, but I haven't been able to actually test it out due to excessive traction/torque ratios. Works in the one gravel parking lot I tried it in, but I was well below 25 mph.

You might be able to weld it up, if you welded a chunk of round bar in between the governor counterweight and the case, but then R&R of the unit suffers and there's always the possibility of welding slag/spatter floating around. With the failure of one welded diff under my belt, I'm trying to keep welding slag/spatter to a minimum!

What's a CWP, and why would it need to be realigned?

[volvorsport]

crown wheel and pinion , im just thinking out loud - whenever we took a ford diff apart , the side play needed to be adjusted , of course i said that without thinking about it.

Its possible the side to side play in the bearings is done with a shim thats already in there , and the diff is located exactly in the right place when its put back .

Im asking curious questions since ive never needed to take a diff out !!!

are you saying in normal driving you havent made the locker work !!!!lol

[TerribleOne]

Matt you should be a school teacher! excellent posts.

[volvorsport]

hmm , so what does the govener pawl sit against , is it the case or does it dangle in free space ?

im thinking a stainless steel band with notch on it that presses the pawl inwards at all times clipped against the case - that way , its completely reversible .