Front Locker Performance in a 2nd Generation Explorer

[Hokie]

Originally posted by JDraper
What I am working on will only work on the '95 and '96 Explorers with the vacuum disco front axle. It won't work on the 97-up. The brown wire mod is the only way to do it on them, unless you drop a 96 axle into the truck.

So first gen Ex's with a front locker and manual hubs can just lock one hub and let the other one spin while driving in snow?

 

[JDraper]

Yep. Works like a charm

 

[Lefy]

after reading this thread three times..
and wheeling after reading it i want lockers. front and rear.

thats it i'm saving up for them.
it's descided.
and i mights as well regear while i'm at it. maybe 4.56s and 33s makes up for my 4.0 sohc sucky power.
what do you guys think or is that too low.

 

[Rx4phun]

4.56s wont be too low. If you had 3.73 like I do stock and went to a 33" tire the equivalent gearing would be a 4.26 I think it was. They only make a 4.27 for the rear and you certainly cant have different ratios in the front and back so it is either 4.10 or 4.56. 4.10s came stock on the 29s so I would go 4.56. If and when I regear I will do that and probably lock the rear with a Aussie Locker, the review on pirate4x4 looks really good. I wont lock the front b/c I do good deal of snow driving, so I need the front engaged but dont want it locked. (I did the brown wire mod, and on a side note it hasnt helped my mileage b/c the temptation to spin the tires now overwhelms me sometimes)
Gary

 

[JDraper]

AH-HA!!!!!!!!!!

I figured out how to manually control the vacuum disconnect!! . Check out http://www.explorerforum.com/forums/showthread.php?s=&threadid=88718!!!!!!!!!!

 

[Hokie]

So let me get this straight. On the vaccum axles, you can make your truck 3 wheel drive? Dang, lucky summa gun. The only option for us later guys is the brown wire mod which is really just the front driveshaft on/off right? (I have done this mod, but i need my front axle in the snow)

 

[GJarrett]

Originally posted by Lefy
and i mights as well regear while i'm at it. maybe 4.56s and 33s makes up for my 4.0 sohc sucky power.
what do you guys think or is that too low.

If you have 4.10 you won't even have to change at all. SOHC w/4.10 gears worked fine for me with 33" tires so 4.56 would be even better. Now that I am on 35" tires, that made enough difference to force me to regear, I'm now 4.88

 

[Robert]

4.10s and 33" tires sucked bad enough to me to convince me to go to 4.56s. My mileage didn't change a bit, but my power off the line has greatly increased. The deciding factor to me was when I got beat off the line by an early '90s Ford F250 deisel pulling a landscaping trailer full of lawn mowers. When I got home placed my order for 4.56s to put me back at my stock overall gear ratios.

Gerald - please see my thread: http://www.explorerforum.com/forums/showthread.php?s=&threadid=89086 and make comments appropriately, thanks.

 

[Robert]

Gerald - Another question, did you put a no-slip in the rear first and have it in for a while before putting the front one in? I remember discussing this with you several months ago and if you'll remember the reason I decided not to go with the fron locker also was because I didn't want to give up my Auto 4x4. Well it turns out that evern with just the rear locker, I have to turn my Auto 4x4 off anyway. If I dont', I can feel the front trying to engage after I've made several turns. I beleive that since both rear tires are now affectively locked, my rear driveshaft is turning at a much different rate to my front one than it did with a rear limited slip. After making 3 or 4 turns, I would get a loud "moaning" sound and the steering would get very stiff if I left my Auto 4x4 on. I just leave it off at all times now unless it rains or I am in the dirt. On the dry pavement, I don't really need Auto 4x4 anyway, but I was just wondering if you experienced the same thing. If I remember though, I think you did away with your Auto mode compeltely by installing an Atlas transfer case.

 

[JDraper]

I could use my truck in Auto 4x4 without a problem with the Powertrax installed. I only have 3.55's, but I don't think that would make a difference. You sure you don't have a sensor going south that might be messing up how the Auto 4x4 engages?


Also, why would your driveshaft turn at a different rate?? You still have the same gear ratios, and the locker doesn't affect that. If your driveshaft were turning at a different rate, the wheels would also be forced to turn at a different rate.

 

[Robert]

My theory is that with an open (or loose limited slip) in the rear, only one rear tire is actually driving the truck. Depending on whether or not the inside or the outside tire is being driven will determine how fast the rear driveshaft is spinning. Actually, the rear driveshaft speed will determine how fast your are rounding the turn, but it is only completely connected to one rear tire. The other rear tire will just be along for the ride (the reason for an open or limited slip differential). If the inside tire is the tire being driven, the driveshaft will spin slower than if it were the outside tire being driven. The reason is the outside tire has to travel almost twice the difference in the same amount of time due to its longer arc. Now lock both tires together and make the same turn. When coasting around the turn with a powertrax, it isn't a big deal since it should mimic an open differential when no power is applied. However, maintain a constant speed or accelerate in the turn and both tires will have to spin at the same speed since they are mechanically locked together. This means either the insed tire will spin faster to match the required speed of the outside tire or the outside tire will be drug around the turn as it turns slower than required to match the speed of the inside tire. The third possibility is that both tires will squeel and howl as they fall somewhere in between. My experience with my no-slip is that it is my inside tire that is squeeling as I round the corners.

Back when I had my factory rear end, when I gave it too much gas when rounding a sharp turn, it was my inside tire that would spin (based on the location of the rubber marks left) which leads me to believe that in a factory setup, the inside tire does most of the driving when turning. Now with my locker, I am led to believe that my outside tire is doing the driving (based on the side that I hear the squeel come from). Since the outside tire has to turn almost twice as fast as the inside tire since the distance is almost twice as far, in identical turns (one with a factory differential, the other with the locker) this leads me to believe that my rear driveshaft is now turning almost twice as fast with my locker in the same turn as it used to with my factory differential.

Since my front differential is still completely open, its characteristics haven't changed so my theory is that with my locker, my rear differential is now turning almost twice as fast in relation to my front differential as it did with my factory differential which is enough of a difference for my Control Trac to think the rear tires are slipping which then starts diverting torque to the front wheels (which I definately feel).

I am certain that my speed sensors are fine since the problem only showed up once the no-slip was installed. Also, my experience with regards to faulty speed sensors, is that when the front one fails, it will cause all power to sent to the front wheels at all times until the 4x4 and Low lights flash once the GEM detects there is something wrong. If the rear sensor fails, then the lights will immediately flash since the GEM believes that the rear tires aren't getting any power (which it knows to be untrue since the default mode is 96% power to the rear). If it were just a matter of a loose connection to my transfer case, it wouldn't be nearly as repeatable as it is. It would show up much more randomly.

I don't know, maybe I am just thinking too much The problem only shows up after making 3 or 4 90 degree turns with my Auto engaged and it only started showing up the day I picked up my Explorer after getting the gears and locker installed. Since they didn't mess with my trasfer case, I don't think they bumped the harness. I'll check it out though just in case.

 

[JDraper]

You're thinking too much about it . If the inside wheel is driving, your truck will be doing a set speed for a given driveshaft rpm. If the outside wheel is driving, your truck will be doing a lower speed for the same driveshaft rpms. I don't think it's the locker.

I've re-written the next section about 5 times over the last 10 minutes as I think about it............If I remember correctly, the computer uses the abs sensors on the front and rear axles to determine if the tires are slipping.


After sitting here and erasing about 15 lines of thoughts and ideas, I think it could be the gear ratio change that is causing this. If the computer is programmed for a certain gear ratio range, say 3.27's to 4.10's, it will expect to see up to a certain amount of variance in rotation between the front and rear axles when you corner and ignore those variances as coming from cornering. As you go higher in gear ratio's, the variance in rpm between the front and rear axles will become greater, possibly crossing the computer's threshold for engaging the front axle. Even without the locker, there are times when the outer wheel may drive, and times when the inner wheel may drive, so the computer must be able to compensate for this.

I'm gonna post this now before I erase it again and start over. If I have any other random thoughts on the subject, I'll post 'em

 

[GJarrett]

Robert, I answered in your other thread, something is wrong - I have never had the clunking problem. I installed my rear locker a couple of years ago, the front was not available then. My rear does not engage unless I give it a fair amount of power - I can go into a turn with conservative power and not worry, I've got to punch it a little to make it engage. I guess I drive more conservatively than you

I did the brown wire switch trick to manually disconnect my 4auto; I do not have an Atlas (Ray Lobato and Jefe have an Atlas).

Sorry that I'm not more help.

 

[Robert]

JDraper - the problem is that I regeared to 4.56s to offset the added diameter of my 33" tires. My overall ratio is as close to my original stock ratio as it can get. It's not the ABS sensors that determine whether or not the front kicks in, it is the speed difference of the front and rear driveshafts (measured at the transfer case by two speed sensors). Since my overall ratio of my 4.56 gears and 33" tires is only 1.2% faster than my stock 4.10 gears and 30" tires, I don't think the problem is due to the gear change. I was actually much farther out of the factory ratios for the three months of having my 33" tires on and my 4.10s and never had any problem with the Auto engaging. Though the difference might have been due to the fact that my RPMs were much lower than what Ford designed. Now I am running 1.2% faster than their highest designed ratio but that should still be well within acceptable limits since the front and rear speeds can differ by more than that every time I turn.

I've got a new cross pin on order from Randy's which should cure my other problem. I'll take a look at my transfer case wire harness while I am under there to replace the cross pin. I know right after I had my transmission rebuilt, the place didn't get my harness plugged in correctly. The first turn I made in their parking lot felt just like 4x4 high. The Technician crawled underneith and unplugged the harness and then plugged it back in. It never acted up again until I got the new gears and No-Slip. It may very well be the connector again, since it appears that everyone else with the Auto 4x4 hasn't experienced the same problems that mine is so it probably isn't related to the gears and No-Slip.

 

[JDraper]

Oh well, it was a random thought on the fly. As I said, I was thinking, writing, erasing, and trying to work all at the same time . Some of the stuff I erased was similar to what your post has in it. Glad to see it seems your on the track to solve the Powertrax issue.

 

[jobunn]

Well it turns out that evern with just the rear locker, I have to turn my Auto 4x4 off anyway. If I dont', I can feel the front trying to engage after I've made several turns. I beleive that since both rear tires are now affectively locked, my rear driveshaft is turning at a much different rate to my front one than it did with a rear limited slip. After making 3 or 4 turns, I would get a loud "moaning" sound and the steering would get very stiff if I left my Auto 4x4 on. I just leave it off at all times now unless it rains or I am in the dirt.

Robert, this sounds exactly like the problem I have. I often do get a "moaning" sounds, a little "clunking" and the feeling that power is being shot in spurts to the front, but only when making a turn and on the gas a little. It really does not bother me but it is noticeable. I THINK I did not have this problem before the No-Slip, but either way I have been feeling this intermitently for a year and a half and it has not gotten any worse. I have stock 3.27's and 31's. Since making the modification to the brown wire this obviously no longer happens.

 

[Robert]

Jobunn, yup, that's what mine is doing. As soon as I felt and heard it, I turned my Auto 4x4 off. The few times since then that I have tried it again, the results were the same so I just leave Auto 4x4 off all the time now unless I am on a slippery surface. Last week I went camping and ended up driving about 30 miles down a dirt road. I renabled Auto 4x4 as soon as I hit the dirt and it worked as expected with no funny sounds. I shut it off again though as soon as I got back to the pavement.

 

[BenS]

Hrm, as a 1997 sport owner in the snow belt I am inclined not to get a front lockright. But I want one for offroad. I need to figure out if I can handle driving the whole winter in 2wd or if my wife will let me take her X every time there's significant snow and i have to go to work...

 

[JDraper]

A quick update on the on-road performance of a '95-'96 Explorer equipped with a Powertrax Lock-right in the front axle and a manual override on the vacuum disconnect. I have now put quite a few miles on the road with it installed. I have driven on 4 lane highways and twisting back roads, and I cannot tell it is installed. I have had absolutely NO adverse handling issues, and it performs as if the locker wasn't even there. If you offroad, PUT ONE IN THE FRONT AXLE!!! You won't regret it!!

 

[Josh Adams]

I need to fully understand something. If 4x4 is not engaged, there will be NO locking of the locker is that correct.

Since I have a Ranger, I am in 2WD most of the time, so that means in 2WD, the locker is not engaged?