ayoung101

question. i've had my truck since late march and got it into 4wd for the first time the other day. i have never owned a 4x4 before and don't know if this is normal or what. (for the record, i have a 22re 5speed, 89 4runner). i took it into the backyard of my girlfriends family's house (which probably wasn't a good idea to begin with, since her dad baby's the lawn)(even though i think it still looks like crap, but whatever). i got out and locked the hubs (manual locking, obviously). got in, started her up, and shifted down to 4-hi. no problem. drove around the yard and up and down their hill and came back to where i started. put it in 4-low and drove around. i could definitely feel the difference of it being in 4wd vs 2 wheel drive as well as 4-hi and 4-low.

the FIRST thing i was confused by was that when i held my clutch in and was NOT braking, i had 2 different reactions in 4-hi. 1st, normal clutch in reaction = ROLLING. 2nd, definitely felt a deceleration motion like i was either braking or NOT clutching all the way to a stop (fairly quickly in comparison to if i was just coasting), came to the complete stop like i left the clutch up but DIDN'T stall.

the 2nd thing was that i had some problems shifting OUT of 4wd into 2-hi. it just physically would NOT go back in to 2wd. i drive it back and forward a bit and then it shifted back into 2wd without a problem.

are these normal? the 2nd one sounds more normal to me (even though i don't understand 4x4's or tranny's at ALL). it sounds like the teeth just weren't lined up and moving it helped to adjust them and align then so that they could line up the teeth. but i'm baffled by the first one.

also, anyone who wants to go wheeling this summer and is near southwestern michigan, let me know.

Mystickal

Remember that when you are in 4 wheel drive, that all four wheels are coupled together. So (ignoring lockers, limited slips, and the like) when you are coasting, the front wheels/front driveshaft and rear wheels/rear driveshaft are all spinning together (and spinning the transmission). This is nearly twice the drag as when you are in 2 wheel drive, because in 2 wheel drive only the rear wheels/rear driveshaft are mechanically coupled to the transmission. So basically, you have more drag.

Your second issue sounds like the diffential had engaged but not unlocked. If I shift from 4-Hi to 2-Hi on the fly, I'll usually stay in 4-Hi until I come to a stop (sometimes even after that) because the teeth are still meshed together. A quick tap in reverse (while in 2-Hi) should unlock the teeth and actually move you into 2-Hi.

~Bill

ayoung101

yeah, that's what i was getting at for the 2nd part. you explained it a crapload better than me though. so the 2nd thing is NORMAL then, correct? for the FIRST part, that would make sense if it happened EVERY SINGLE time i let off the gas, but it doesn't. maybe 1/2 and 1/2.

Mystickal

Your second issue (from the '96 owner's manual):

To shift from "H4" to "H2", simply move the front drive control lever.

This can be done at any vehicle speed.

If the indicator light odes not go off when you shift the transfer into "H2", drive straight aheah while accelerating or decelerating, or drive in reverse.

So yeah, that's normal.

As for the first issue, I still don't think that's abnormal. I would imagine that when you're coasting "normal" that the diff isn't locked. Remember that unless you have a locker, that the wheels with the least amount of traction are the ones that that get power. This can cause unusual situations. Though someone on the board with more 4-wheel experience than I can probably explain it better.

~Bill

superjoe83

im not sure on the first part, but the second part i can explain, it is caused by drivetrain wind up, when you are in 4wd both drive lines have to turn at the same speed, because they are mecanicly linked together, so when you are in 4wd slight differences in tire dameter will bind up the drivetrain and also when you steer, that will also bind it up, and you will not be able to shift it until you relive that stress by backing up or turning back and forth slightly while putting pressure on the transfer case shifter, so when the stress gets relived it will slide out, but in 95.5 with the taco and 96 with the 3rd gens, toyota did something different, they made a spring loaded transfer case shifter so that you can move it out of 4wd, but it will acually remain in 4wd until the driveline bind is relived, it wil then shift into 2wd by spring force, i hope this clears it up

motrhedx81

One thing I will tell you with your truck is DO NOT!!! do any kind of shifting in and out of 4wd while you are moving. I have the same setup as you and your transfer case is gear driven. If you decide to shift into 4wd at speed your transfer case will BLOW UP. What these guys are talking about is "shift-on-the-fly". The reason they can shift into 4wd at 45 mph is because they're t-cases are chain driven, and I think they are sychronized like a multispeed bicycle, allowing it to shift gears at speed.

Always lock your hubs before you get into 4wd. Once your all shifted in, go in reverse about 10 to 20 yards, this locks everything up in the front. Then you're ready to roll. When you're ready to get back into 2wd:stop, unlock the hubs, and reverse about 10 to 20 yards again. With the hubs unlocked, this allows everthing to unlock and you can shift your t-case back into 2wd. It sounds like alot of work but this setup is a crapload stronger that the chain drive t-cases and automatic hubs.

I'm about 99% sure on everything I've told you, but if anyone has anything to correct me on, feel free.

ayoung101

it DOES say that i DO have shift on the fly capabilities. i read that directly out of my owners manual. it said i don't need to be stopped (or even brake), don't need to clutch, and i don't even need to let off the gas. i thought that was a little wierd and so i decided that i would try to never do it unless i was in a really sticky situation (like coming up on a no-warning slippery spot on the freeway in winter) where i started to biff it.

Glenn

I don't know why you think that shifting in and out of 4wd while moving is bad. There is nothing wrong with it as long as the hubs are locked and you are not on the gas too much.



Nothing will blow up. It has nothing to do with whether it is gear driven or not. As long as the hubs are locked, you can shift in and out of 4wd high.


It has NOTHING to do with chain drive or gear drive. "Shift on the fly" is Toyota's way of saying that you can shift into 4wd high if you have ADD. You can shift into 4wd high with the hubs locked at any speed. Some might say <45 mph, but I have done it at higher speeds with no problems whatsoever.


More wrong information here. There is no reason to back up if you have manual hubs. It does nothing. This is for people with automatic hubs (not ADD).


When you are ready to shift from 4wd high to 2wd high, drive in a relatively straight line and start easing the lever from 4wd to 2wd. This will relieve most of any binding in the drivetrail that may be there. There is no reason to do all this backing up. Most of the time, there is no room to back up 20 yards.

motrhedx81

I'm going off what one of my friends said. He was driving down the road and a girl that was riding with him hit the t-case shifter and it blew up his t-case. On the visor in my truck it says NOT to shift into 4wd unless you are under 5 mph and not unless the hubs are locked. I don't know about that ADD stuff, don't have it and don't know much about it. I'm going on personal experience and what I've heard and read. I just hope you're not calling me stupid.

Glenn

Sounds like the hubs were not locked.


Does that pertain to 4wd LOW range? Sounds like it to me.


Nope. I am not calling you stupid at all. If the hubs are locked, the front drivetrain is moving along at the same speed as the rest of the drivetrain, and you can shift into 4wd high at nearly any speed. All that you need to do is mesh two sets of gears that are going along at the same rate of speed. It helps if you aren't on the gas too much when doing this because there is less tension on the gears. That is what "shift on the fly" with ADD does. If you have manual hubs that are locked, you have essentially the same capability to shift on the fly. I have shifted in and out of 4wd high at 75 mph with no problems, but that doesn't mean that anyone else should do the same. And there is no need to back up with manual hubs unless there is already a lot of binding and you have no room to move forward.

I have been driving manual hub 4wd trucks for over 20 years. There really is no mystery to how the system operates.

Plays_with_Toys

He's not calling you stupid. The only way to learn is to find out information.

When you have your hubs locked it spins the front driveshaft , though it is not connected to the T-case, so if you shift into 4wd while moving both driveshafts will be spinning at the same speed, so no problem. With unlocked manual hubs, the front driveshaft is stationary, so at speed, you are making the tcase move the large driveshaft from a dead stop to whatever high rpm you are at (driveshafts are spinning much faster than the tires, because there is another gear reduction in the diffs, so just imagine the strain). So don't shift while moving with unlocked hubs, and also be weary about shifting into 4wd if your backtires are spinning (without traction) with the front hubs locked, because again, the driveshafts will be going at different speeds. 4low you should always stop to shift into, this is just good safe practice. Also, don't drive over 25 mph in 4lo, because the gears and everything are spinning 4-5 times as fast. You can blow things up this way.


Ayoung, one tip listed in my owners manual, maybe even yours is to goose the throttle while putting pressure on the stick to move from 4wd to 2wd. It works for me everytime. I've never had a problem getting out of 4wd since I discovered this. You don't have to go ape wild, just a quick romp on the gas will do it.

motrhedx81

Ahh got ya. Sorry, didn't mean to sound like an a$$. Now it makes sense. Thanks for the good explanation. I didn't get an owners manual with the truck when I bought it off the guy, so that didn't help any.

toy283

The answer to the second part of your question is also the answer to the first part. Driveline bind will slow the vehicle to a stop while coasting. If the front wheels want to turn at a different speed than the rears (due to a current or previous turn or slight variations in diameter) the resultant drag on the driveline will act just like brakes. Nothing you can reley on but it is a side-effect of a 4wd system.

Flamedx4

Toy283 has the answer here guys. No mystery here. There is usually a small diameter difference between the front and rear tires and it matters. If there's a bigger difference (like say if the fronts are real low, or if you're an idiot and don't even have the same size tires front and rear) it will cause the case to bind and not want to come out of 4hi. Another thing, more importantly and this is probably what happened to Young101: drive straight and turn the wheel just slightly side to side. In 4wd bind occurrs in the t-case due to turning too.

Oh, and when coasting with the clutch pedal depressed and turning the wheel even a little bit in 4wd will cause bind, and will feel just like brakes, if the tires had nice grip on surface you're on. Backing up a teensy bit does help, they aren't wrong about that, it can help unload the t-case.

Shifting on the fly above 45 is certainly possible, but you should really try to avoid it. If there is any difference in tire diameters (due to inflation) it's amplified as speed increases. But even in practical terms - if conditions cause you to need to yank it into 4hi, you probably need to Slow the Farg Down anyway! <grin>