BonkersBaja
Forum Member
Built a torq locker into front diff while building a selectable locking center diff mod. Obviosly great traction. Did it just to see how it would handle. For those wondering, no one is not available. The machining costs to do what I did would be crazy like thousands of $$. I was able to do it only because I had access to all the required equipment and could machine myself. No I'm not ready to do for others, but I will share how. What is involved? How does it handle? What did I learn?
I put a 5-bolt locker from a rear into the front.
--It is a little small, so I had to build shouldered bushings to position it correctly.
--Had to normalize the cross pin and reduce the center portion to the pin diameter of a 5-bolt diff. Leave the ends original diameter to seat in diff. Re-harden
--normalized stub shafts for axles, reduced diameter at inner splines to spline diameter of 5bolt rear shafts. Re-spline to match 5-bolt, re-harden
That much worked... but handled poorly on road after an already huge investment. The lockers take a while to break-in/polish and work smoother. I found that it caused significant oversteer/understeer particularly at near dead straight as the locker was uncertain whether to lock/unlock and car would veer either direction somewhat unexpectedly. This was especially profound under hard acceleration veering as much as a foot unexpectedly.
So realizing that when putting torq lockers in the rear, they eventually smooth out and work better, I decided to see if those quirks could be remedied. Torq lockers default to locked... they are automatically unlocked. So I decided to focus on improving efficiency of unlocking.
Here is what helped dramatically.
--reduce the shoulders I built on side bushings to allow needle roller thrust bearings
--used lighter springs in the lock
--tumbled the machined lock pieces with stainless steel pellets and very fine grit in rock tumbler to put a fine polish to all surfaces (optional $$ processes)
-- built bushings that fit slightly loose over splines that take up gap between cross pin and side gears to keep axles from occasionally moving them inwards
--Cut a flat on top and bottom of shoulder of crosspin that fits the diff housing opposite of it's roll pin. Necessary for assembly with spacer bushings above.
With these mods, the locker works very well. Road manners aren't perfect... but good. Under heavy acceleration it still has some over/under steer near straight line but now only swerves an inch or so unexpectedly. If driving with light acceleration, it's completely unnoticeable.
One other thing to note. If the center diff isn't an efficient open, then the front and rear will be working against each other on turns. Even a LSD will cause the front locker to ratchet loudly and sometimes start lurching. Mine is an open with vacuum actuated lock from an 87 XT. With this arrangement, it remains nearly silent and smooth. I am delighted with how it drives offroad being always locked front and rear with a center lock available. The road manners are good... and after a week or so, you just learn to drive it so that you'd scarcely know it was modified.
In case your curious, I also built a lengthened 4.11 output shaft to go with the selectable center lock as well as put in 1.59 dual range gearing, lifted it 4 inches, 29 inch rubber, swapped in H6. Everything works... AC, cruise control, ABS...everything. Pretty much it drives like a sports car, hauls like a mini truck, and climbs like a jeep. If Subaru had sold this Baja configuration but with a LSD front for perfect handling, they'd have sold a great many more of them.
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I put a 5-bolt locker from a rear into the front.
--It is a little small, so I had to build shouldered bushings to position it correctly.
--Had to normalize the cross pin and reduce the center portion to the pin diameter of a 5-bolt diff. Leave the ends original diameter to seat in diff. Re-harden
--normalized stub shafts for axles, reduced diameter at inner splines to spline diameter of 5bolt rear shafts. Re-spline to match 5-bolt, re-harden
That much worked... but handled poorly on road after an already huge investment. The lockers take a while to break-in/polish and work smoother. I found that it caused significant oversteer/understeer particularly at near dead straight as the locker was uncertain whether to lock/unlock and car would veer either direction somewhat unexpectedly. This was especially profound under hard acceleration veering as much as a foot unexpectedly.
So realizing that when putting torq lockers in the rear, they eventually smooth out and work better, I decided to see if those quirks could be remedied. Torq lockers default to locked... they are automatically unlocked. So I decided to focus on improving efficiency of unlocking.
Here is what helped dramatically.
--reduce the shoulders I built on side bushings to allow needle roller thrust bearings
--used lighter springs in the lock
--tumbled the machined lock pieces with stainless steel pellets and very fine grit in rock tumbler to put a fine polish to all surfaces (optional $$ processes)
-- built bushings that fit slightly loose over splines that take up gap between cross pin and side gears to keep axles from occasionally moving them inwards
--Cut a flat on top and bottom of shoulder of crosspin that fits the diff housing opposite of it's roll pin. Necessary for assembly with spacer bushings above.
With these mods, the locker works very well. Road manners aren't perfect... but good. Under heavy acceleration it still has some over/under steer near straight line but now only swerves an inch or so unexpectedly. If driving with light acceleration, it's completely unnoticeable.
One other thing to note. If the center diff isn't an efficient open, then the front and rear will be working against each other on turns. Even a LSD will cause the front locker to ratchet loudly and sometimes start lurching. Mine is an open with vacuum actuated lock from an 87 XT. With this arrangement, it remains nearly silent and smooth. I am delighted with how it drives offroad being always locked front and rear with a center lock available. The road manners are good... and after a week or so, you just learn to drive it so that you'd scarcely know it was modified.
In case your curious, I also built a lengthened 4.11 output shaft to go with the selectable center lock as well as put in 1.59 dual range gearing, lifted it 4 inches, 29 inch rubber, swapped in H6. Everything works... AC, cruise control, ABS...everything. Pretty much it drives like a sports car, hauls like a mini truck, and climbs like a jeep. If Subaru had sold this Baja configuration but with a LSD front for perfect handling, they'd have sold a great many more of them.
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to the forum.
Jon M
