ADD reverse question
 

i was wondering if you have an ADD diff is there anyway to prevent it from unlocking when you go into reverse? is there an electrical circuit i could redo so the acuator put suction on the lock side other then the unlock side when in reverse?

:think:

:wabbit2:

is there any way to make it so the add hubs stay locked when your backing up?

ADD hubs are drive flanges and don't unlock.

AUTO hubs are a clutch system hub that do unlock in reverse.

Only like pre 89 could have auto hubs it seems.

:wabbit2:

when i say add hubs im refering to the sleeve in the differential thats acuated by vacuum. sorry it seems thats the common term for them.

So you lose 4WD in reverse?

That can't be normal but again I cut IFS off more than I troubleshoot it. Interested to see what develops.

:wabbit2:

if im not mistaken the sleeve disconnects after like a 1/4 rotation in reverse

What year is your truck? Im pretty sure that its just auto hubs that disconnect in reverse. Im guessing 86-89. I know my 93 stays in 4wd in reverse.

Uh...definitely should NOT do that... How do you know it does? What year is your rig?

The sleeve is vacuum actuated, locks with vacuum and unlocks with vacuum:
- http://www.off-road.com/trucks-4x4/t...tem-19259.html

Might be thinking about the situation where you are in 4WD on a high traction surface (binding up the drive train) and then try and shift to 2WD. Due to the binding, the sleeve may not unlock right away, but it eventually will once the binding is relieved, like what you shift to reverse and back up a little.

its a 93 4runner with add i havent tested it. i could have sworn they did but i guess not.

Im sure they stayed locked. What you probably noticed was that one tire was spinning and the other one wasnt and this is due to having open diffs. So your 4wd isnt exactly 4wd without a locker

no i havent even takin the truck offroad(dont have a license) but since i have the motor out and room to work with i was wondering if there was a way to do that but it appears that its not an issue to begin with.

Auto-hubs unlock when you reverse.
Automatic Differential Disconnect (A.D.D.) does not.

Auto hubs were an option on trucks from '84-'88 and 4runners from '84-'89.
'89-'95.5 trucks had manual hubs or ADD. '90+ 4runners had ADD only.

well since u have the motor out and have room, just remove the whole thing and put a strait axle on it, then u will like your 4runner even more.

Hey this is the closest thing I could find to my problem. I rebuilt my passenger side hub recently and when I tested everything out after re-installing, everything worked except 4wd reverse, any ideas why? Reverse worked 2wd, and 2wd with the hubs locked, just not with the power to the front wheels. When I try to reverse it starts to feel tight and bound up like the tire isn't rotating. Could it be I just didn't re-install the hub properly? I notice this hasn't been active for a while, but just didn't want to start a new thread with out checking here first.

everyone says the auto hubs unlock in reverse but my 87 never seems too. I have been stuck a few times and all 4 spin in reverse. Im still getting manual ones though...just havent had the time to fight the cone washers on my parts truck.

They unlock in reverse then re-lock. They unlock with a change in direction momentarily nobody is saying you dont have 4wd in reverse. Its just not as good as locked hubs cause theres a delay in 4wd engagement between forward and reverse, just enough to use it as an excuss why you got stuck. And unless you have lockers then all 4 dont always spin, sorry its impossible to have 50/50 traction all the time.




The way it works, its not rotation specific, it doesnt know weather its going forward or backward. Its just a mechanical coupler. However its possible for an electrical malfunction to take place involving the reverse sensor and the 4wd's electronic components, making it shift out of 4wd when its in reverse, but thats a different issue altogether.

ok i get it now...i misunderstood the way they work. And i just meant i 4wd is engaged in reverse....i know its just going to be 2 or 3 wheels spinning with open differentials.