Differential Lock

[DoubleD]

A while back I owned a Subaru XT6. I loved and hated that car, an XT 4 cylinder turbo would beat it. I seem to remember that the XT had a differential lock button. The car has awesome traction. In extreme conditions, engaging the differential lock made it better.

I know cars have come a long way they have computers and sensors that try to automate everything for you BUT sometimes I like having the option of being in control. Does anyone know if there's a Hack/Tip/Trick/Mod that can be made to the Baja so that the AWD differential can be locked ?

I'm not sure how the Baja does it AWD but I'd love to be able to lock it in. I kind of lost traction backing out my driveway, getting through the snow that the plows left me at the edge of the driveway. I know my XT used to do that and hitting the differential lock would fix it. The Baja I had to go forward and get a slight running start.


Does anyone know if there's a Hack/Tip/Trick/Mod that can be made to the Baja so that the AWD differential can be locked ?

[Nitro350Z]

There's no easy way to do it. The center differential is a viscous unit that splits torque 50/50 f to r or 60/40(?) if you have an auto gearbox, your rear diff is a viscous type as well, and the front is open.

You might be able to replace the center diff with a clutch-type (not sure if anyone makes one though) or you can take it apart and weld it but you'll probably run into issues down the line since it wasn't designed to be locked up like that. As far as I know nobody makes locking diff's for Subaru's.

If you're looking for the most grip, the best route is good snow tires. Even with open diffs you'll get plenty of traction to pull you through what you'll encounter on the road, if you're set on more expensive mods the next best thing is to throw in clutch-type diffs into the front and rear and call it a day. That should let the car use the available traction to the fullest without going crazy doing custom fab or fitting a dccd to the 5MT.

[DoubleD]

There's no easy way to do it. The center differential is a viscous unit that splits torque 50/50 f to r or 60/40(?) if you have an auto gearbox, your rear diff is a viscous type as well, and the front is open.

Thanks for the reply

I have auto trans so I guess is 60/40

I thought it was electronically controlled and I swear I had it in the XT 6. If it was electronic and they did it in the old version then it may have been replicable but I guess not

[DoubleD]

This kind of what I was thinking

http://www.rs25.com/forums/f8/t99075-4e ... -lite.html

[Nitro350Z]

Reading through that thread I think I understand what you're getting at, forgot that the diff in the auto can split the torque up to 90/10 f/r on the auto. A mod like that would definitely improve driveability in slow low traction conditions. After that mod it's still a viscous diff, there's no locking, it just keeps the torque split at 50/50 f/r like you would have in the 5MT.

This might help clear things up about torque split if there's any confusion about it: http://www.awdwiki.com/en/torque+split+ratio/

If you're feeling up to doing that mod, go for it, seems like it would be pretty much what you're looking for. Don't forget to let us know how it goes. Good luck!

[DoubleD]

Reading through that thread I think I understand what you're getting at, forgot that the diff in the auto can split the torque up to 90/10 f/r on the auto. A mod like that would definitely improve driveability in slow low traction conditions. After that mod it's still a viscous diff, there's no locking, it just keeps the torque split at 50/50 f/r like you would have in the 5MT.

This might help clear things up about torque split if there's any confusion about it: http://www.awdwiki.com/en/torque+split+ratio/

If you're feeling up to doing that mod, go for it, seems like it would be pretty much what you're looking for. Don't forget to let us know how it goes. Good luck!

This was exactly what I was talking about

I just don't know if the Baja has the 4EAT transmission and where to locate the wires to actually do the mod. If I can confirm I have a 4EAT and can locate the wires maybe I'll try this mod.

[Nitro350Z]

It does have the 4EAT, Subaru doesn't really offer a whole lot of different transmissions, especially in the mid 2000's MYs. You would just have to check if you have VDC, my manual didn't but I don't know if it's was an auto only feature back then.

I've got access to some wiring diagrams and whatnot if you want to PM me an email I can send them over, they might help you figure out exactly what to do.

[bajaguy]

Let us know how it goes if you do try something! I personally have been in several positions where a locking dif was necessary.

[whitrzac]

Reading through that thread I think I understand what you're getting at, forgot that the diff in the auto can split the torque up to 90/10 f/r on the auto. A mod like that would definitely improve driveability in slow low traction conditions. After that mod it's still a viscous diff, there's no locking, it just keeps the torque split at 50/50 f/r like you would have in the 5MT.

This might help clear things up about torque split if there's any confusion about it: http://www.awdwiki.com/en/torque+split+ratio/

If you're feeling up to doing that mod, go for it, seems like it would be pretty much what you're looking for. Don't forget to let us know how it goes. Good luck!

Nope, it fully locks the center diff. The auto uses a clutch pack similar to the STI 6 speed.

With a 5spd, 1 wheel of the ground and you go no-where.

With the 4eat you can get 1 front and 1 rear off the ground before you have issues.

[DoubleD]

Nope, it fully locks the center diff. The auto uses a clutch pack similar to the STI 6 speed.

With a 5spd, 1 wheel of the ground and you go no-where.

With the 4eat you can get 1 front and 1 rear off the ground before you have issues.

Hey whitrzac so you are saying that the Baja Automatics (Turbo or Normal Aspiration) use the 4EAT ?

Yes/No?

[Nitro350Z]

huh, son of a gun, looks like I'm wrong. It locks in the sense that the maximum amount of pressure is put on the clutch pack, I'm not sure that actually translates to a 100% lock, but even if it isn't that seems much better than the viscous coupling in the manual for sure. If I'm reading the service manual correctly all of the Subaru autos should be able to go into this mode, with the VDC equipped models having a bias towards playing with the center diff before using brakes and reducing engine output to regain traction.

Maybe the TCU is really that slow at responding, seems like it would be a worthwhile mod to try out.

[whitrzac]

Nope, it fully locks the center diff. The auto uses a clutch pack similar to the STI 6 speed.

With a 5spd, 1 wheel of the ground and you go no-where.

With the 4eat you can get 1 front and 1 rear off the ground before you have issues.

Hey whitrzac so you are saying that the Baja Automatics (Turbo or Normal Aspiration) use the 4EAT ?

Yes/No?

Subaru 4 speed autos didn't change much for ~15 years... Some used a 12v PWM signal to lock the diff, some were 'natively' locked until power is applied.


With the CD locked, I could get to ~3k RPM in 1st before it slipped on my 220k forester. I would call that 100% lock

[Rizzo]

I had 3 on the ground and got out of a jacked up hole down a road the county has forgotten about,I got out.