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4x4 actuator upgrade

jbsaxman said:
OK, so is there any detriment to keeping the front diff locked all the time? I know that you'll get the front tires fighting themselves if you crank it while it's in 4WD, but what about if the transfer case is in 2WD?
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Posi lock actually sells a full time lock kit for the front axle. Myself I can't see any reason to worry about the front end being locked all the time. It's basicly the same as a front wheel drive system in a car. As long as you leave the transfer in 2wd it won't bind up but if you forget it will. However thats also true of the stock setup.
 
I was thinking about getting that full time locker rather than the posi-lock. I really don't see a problem keeping the front diff locked all the time, either. Just wanted a second or third opinion.

I've never really looked, but the rigs with the lever activated 4WD, does the lever control the transfer case and the electronics in it control the locking of the front diff?
 
I've got an older 4x4 with manual hubs. If they are locked with the transfer in 2wd the front wheel work against each other just as in 4x4. Leo
 
NVW said:
I've got an older 4x4 with manual hubs. If they are locked with the transfer in 2wd the front wheel work against each other just as in 4x4. Leo
Click to expand...

True but you are also running 2 u-joints not 4 CV joints. U-joints bind more than CV's do. You might feel some binding but if I remember right about the kit you can also unlock it by turnning a set screw and movint the rod as it is adjustable. Personaly I'd just leave it locked.
 
Does anyone know of a place where they explain how this engagement works preferably with pictures, as it's honestly not clear to me. What happens when I push that button and expect all four wheels to propel me forward?
 
The TLA pushes a rod into a colar that rest on the axle shaft which is split into two pieces where it exits the differential. The colar is splined like any axle shaft and joins both halves of the axle together. So one side of the diff is always turning regardless of 4X4 use. When the transfer lever is pulled a switch sends power to the TLA and move the rod sliding the colar. The only diff between 4X4 and 2X4 is one axle is no longer disconnected. If the TLA or switch fails the power is sent to where there is less resistance (IE the dissconnected axle) much the same as an old solid axle with lockouts. You unlock one hub and presto no 4X4. If you know how a lockout hub works picture that on one side of the diff only the colar simply slide onto the other half of the axle. Hope this helps.
 
What is nice about the posi-lok is you can leave it engaged and all you do is pull the lever back and your in 4x4. After we put the posi lok on it would whine really bad going down the road with the front end engaged. Not to long after there was a gear lube smell and seen a seal blew out on thw front diff. Im not sure if the posi lok had anything to do with the seal blowing out or not. My dad drives around with the posi lok engaged and hasnt had any leaks since.
 
Bullseye240 said:
The TLA pushes a rod into a colar that rest on the axle shaft which is split into two pieces where it exits the differential. The colar is splined like any axle shaft and joins both halves of the axle together. So one side of the diff is always turning regardless of 4X4 use. When the transfer lever is pulled a switch sends power to the TLA and move the rod sliding the colar. The only diff between 4X4 and 2X4 is one axle is no longer disconnected. If the TLA or switch fails the power is sent to where there is less resistance (IE the dissconnected axle) much the same as an old solid axle with lockouts. You unlock one hub and presto no 4X4. If you know how a lockout hub works picture that on one side of the diff only the colar simply slide onto the other half of the axle. Hope this helps.
Click to expand...

Thanks, that explanation accompanied by howstuffworks.com made things a little clearer I think. Only thing confusing now is the talk about keeping the front end locked up without being in 4x4..?
 
If the front differential is locked, that means that if there is something to drive them, they'll turn. The transfer case is only half of 4x4 equation. You also have to have locked hubs (meaning the axles are engaged) so that when the transfer case turns the drive shaft, the drive shaft can turn the axles which will turn the wheels.

Think of it on older style front differentials when you had to get of your rig and turn the thing in the center of your front tires? Otherwise called "Locking the hubs". It's exactly the same thing, only in our rigs is 'electronic'.
 
The transfer has a similar colar that engages the front drive shaft. If you lock the front end the driveshaft will turn but power from the engine will not go to the front axle unless you place the transfer in 4X4.
 
- So that posi lock thing takes care of the front diff engagement (the problem area?).
- The front driveshaft is engaged through the stock system (works fine the way it was originally designed?)

I chose to not think of the hubs for now, it only makes my head spin through the viscous coupling with my brain fluids.. Thanks for helping in trying to wedge some understanding of this into my head. I hate not knowing how stuff works!
 
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I only speak for the lever activated transfer here. I dont know how reliable the electric activated transfer is. But yes the posi lock takes care of the problimatic front axle engagement.
And thats why this forum is here, so we can help each other out.
 
Limited Slip is the G80 option on GMs, better than open (most common/factory normal) but not much, many trucks/most burbs with the Diesel have the G80, check your glove box to see if you have it look for code G80
 
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