I've read quite a bit about this, and am wondering if anyone is running 2 different gears in their truck. I have read where people opinions are anywhere between 1-4% is alright 1-2 street 3-4 dirt.

Is anyone currently doing this that can comment?

I am looking to install an e locker in the rear and keep my current open diff front.
e locker is 4.30

front diff is 4.375.

It is a difference of 1.744%

 

Seems I heard that some old Studebakers came with a 4.10 in the front and a 4.11 in the back so that they would pull straight in very slippery/icy conditions. Don't really know if it's true. The difference between 4.10 and 4.11 is only a hundredth of a tooth, substantially less that your 1.74%, but the setup that you propose has the higher gear in the rear, rather than in the front.

I am interested to hear others input and experience.

I think you would have immediate trouble on any hard, dry surface.

Let us know if you try to run it.

 

Street? You shouldn't be doing that regardless.

Anywho. If my math is correct. That's somewhere around the same difference as running 100% tread vs. 25% tread front or rear(or just different brand tires fr/rr). Which I've done all kinds of. I've had some very minor binding as a result. Nothing I would particularly worry about. Nor has it caused any major driveability issues(none that I was aware of/that were noticeable). Just a little harder to get out of 4WD sometimes, and/or shift-on-the-fly 2WD to 4WD.

 

when I say street, I mean just popping in couple miles here and there not all the time. I don't have any of that bind now, I know I have had it before with different brand tires, different air pressures, or worn differently. currently running 4 matching brand new tires and can pop in and out of 4wd on the fly.

 

I don't think there would be enough of a difference in performance to risk it. Running different ratios front to back could cause more harm than good.

 

Thats not enough to matter, youll be fine.

 

cool I ordered a 4.30 E locker for it. gonna eventually put a 4.30 limited slip chunk in front. but momma aint going for that right now.

also thought I'd run tires 5lbs less air in the lowered geared front to help drop that 1.74% a little lower?

I ordered my switch,14/6 trailer cable, bolts, gasket,and seals last night to do this. pulled my extra rear end apart yesterday
gonna do my welding and cutting this weekend to fit the e locker!!!

I'm excited!

 

You should run lower air pressure in the higher geared axle, not the lower geared one.

 

ok i keep trying to work it out in my head but was having trouble. makes sense I think.

So I'm slowing down the faster axle (4.30) by reducing circumference of its wheel?

I'm thinking like 5 pounds to get it a little closer to 0

 

Yes, this is right.

 

You'll be fine. People run mismatched Toyota and DANA axles all the time.

 

cool thank you. I'll post some picts and details when I'm done. Elocker came today, package from Toyota tomorrow. Hopefully switch, and wire Monday.

 

Saw a guy's post on pirate where a guy was running Dana with 5.38 front and Toy 5.29 rear. Said no problems in dirt.

But also saw a post with pics of a guy running different ratios f/r that gave the frame a distinct A frame look after making a turn on asphalt after unloading rig off trailer. Said frame was rust before the bend.

So overall condition of rig may play a large factor.

 

Muddpigg, dude that A-framed his frame. Were his ratios as close as we are talking?

frame is solid. 2 things it had going for it when i bought it was frame, and bed, not much else.

Got case cut,drilled, and half-arse welded.

Waiting on switch. gonna wire switch in with lights. rear locker will light with lights, then when activated it will have a small indicator light. gonna back light in green to match old style interior lighting..

 

I have no idea what ratios but feel that the frame must've been in really bad shape. Prolly for the best it crapped out in front of his house and not on a sketchy line while on the side of a mountain.

 

I once ran 3.90 in the front, 4.10 in the back (by mistake). On pavement, it would bind after about 10 meters. On dirt/gravel, it worked but the tires were slipping every few turns of the wheels, which chewed up the trail and decreased overall traction. You'll get away with it but it's far from optimal.

 

3.90 to 4.10 is over a 5% difference. My situation is 1.74%

I know not ideal but until I can pony up for a 4.30 front chunk, this is where I am.

Got rear end installed yesterday with no drama cept brake hardlines being old and rounded.

Instead of drilling flange on rear, I replaced the rear companion flange on driveshaft, one from a 96+ Taco or 4runner fits exactly on pre 84 driveshaft. Same u joints too. this also enabled me to use the larger nuts and bolts to attach driveshaft to rear end. (my 80 has 8mm hardware(12mm head) 84+ used 10mm hardware(14mm head)

Still waiting on dang switch.

Bought 14 gauge trailer wire for install, if I had it to do again would have gotten 16 gauge. 14 is overkill

 

Got everything buttoned up yesterday.


Had to cut metal dash behind this spot. Still doesn't seat all the way. Gonna have to grind a tiny spot out of steering column bracket.




Used PCV grommet here to seal wiring




Didn't want to cut wire till I was for sure this was going to be my permanent route, so I wrapped it around upper shock mount. Received pigtail north of short harness so tied in there instead of cutting sub harness. Will eventually make this prettier was ready to test and burnt out when I did this part.




This flange is from a 96+ 4runner. Same u joint and no drilling on reared flange. I think it's like 80 bucks but £ found this one on ebay for 30 shipped. New




All new hardware. No leaks.

 

I used a switched 12 volt on actuator instead of straight to battery. Wired light behind graphic to come on with head lights, and when locker engages a status bar lights up. I found a switched power supply @ the emissions box on kick panel. Also used ground from same local.

 

took the truck over Tray Mountain this weekend, and locker behaved wonderfully. rough road, and only had to use 4wd couple of times, most jobs handled perfectly in 2wd and locker enabled.

No binding between front and rear. small amount on dry pavement, but nothing in the dirt. (won't be running on dry pavement anyway) 4.30 rear 4.375 front

Wifey got herself a 2007 FJ yesterday 6 speed,locker voodoo blue with 83,000 miles. neat little truck going to do the mod where locker can be enabled in any transfer case setting, currently only engages in 4 wheel low..

gotta sell something now though. I want to sell the 87 4runner but I have a nine year old that swears it is going to be her truck one day.