ADD front diff?

Ok ill eat crow, thanks for setting me straight.

when i say the front moves in different directions I mean this because with the driver side axle still being attached to the side coupler, since there is not ADD on the driver side. this, and the fact that the front drive shaft and R&P do not turn in 2wd, would mean the passenger side coupler would be turning backwards (because of the spider gears) so the the inner shaft would be turning backwards correct?

It seems strange to me they bothered synchronizing the T case then if the add was engaged first to speed match the t case and front drive shaft.

 

You would be right in the fact that because there are spider gears if no pressure was applied on the passenger side the differential side gear inter shaft sub-assembly would be turning backwards but because there is a pseudo clutch in there it provides enough pressure to allow it to spin in the same direction. Then when you engage the ADD they are now powered going in the same direction. Thats why when you drive your truck in 4wd on the road your steering now feels heavy even though you have spider gears in the front diff trying to get that outside wheel to spin faster than the inside wheel.

The synchro's in the case are there because the front drive shaft is not moving yet so that gear and the chain are sitting still in the case. The synchros allow you to shift on the fly from 2wd to 4wd once the chain starts moving in the case from the ADD system now being engaged.

 

That would be true if there wasn't a clutch sleeve and actuator fork involved. Your talking of a simple rear axle assembly. Not a complicated front drive system

 

I what some of you are thinking is rue. That the t case shifts into 4wd drive first, taking that drive shaft and the front drive gear and chain from a dead stop to full rotation without a clutch in the t case, could you imagine the jolt you would get every time you shifted on the fly? It would be like dumping the clutch in a car with the stickiest tires on earth and having full traction from the time you dump the clutch. Just imagine taking all of that dead weight and suddenly launching it.

Then, lets go with your argument that it is going in opposite directions. Isn't the drivers side already hooked up to the drive shaft per se? It would be spinning then right? So how is adding power from the t case going to cause the passenger side inter shaft to all of a sudden start spinning in the opposite direction from what it was before? Come on guys.

Thats why there is a kind of clutch in there to keep it spinning it the same direction. You've got to have that entire front system spinning and connected before you bring power to it.

 

from an engineering stand point, putting the tcase in 4hi will get the drive shaft spinning which would get the passenger side side gear spinning the right direction and make the add smoother. that is all

 

the add actuator went out on my s10 and i could put it in 4hi on the go, no problem. just saying

only figured out the front add didnt work because i got stuck in the snow since the front wheels did nothing

 

I'm not talking about binding. I'm talking about steering input here. It s true that the front wheels not turn faster than the rear wheels while in a straight line but when you turn you have open diffs the outside tire will move faster than the inside tire unless your locked in the diff.

So as you turn the heaviness your feeling is from the front drive system being engaged. There will be binding, but that will happen in the case not the steering system.

 

I don't know anything about s10's. Never worked on them.

 

I was wrong, ill admit it.

didnt realize the add had a clutch in it to speed up the r&p and drive shaft

I was wrong

 

Yes, I've actually gotten mine stuck in the snow fully locked.

 

hope this was a friendly discussion for you guys as well. Hope i didnt come across as a dick, not my intention.

Thanks for setting me straight

 

Next time i'm up in Big Bear lets go have a beer and talk about something more fun. Like the economy or something.

 

I'm cool.

 

At least yours was equipment failure. I can't say the same thing in my situation. Big snow bank, too much testosterone= stuck big ass truck.

 

Oh its fun alright......until you get stuck. Then it's just down right embarrassing.

 

eh, even if you get stuck everbody knows you have the most bad ass truck around

 

Thanks man. Appreciate it.

 

someday my reg cab will be SAC'd and 4 linked in the rear and the rear hangover chopped. The 110" wheelbase would be awesome. I will continue my lurking on RST.
Now just to win the lottery

 

Sounds good man. If you ever need any help just give me a holler. except for the lottery bit....I'm playing too.

 

Learning is GOOD!