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elementary question on shifting into 4lo

badmix

badmix

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took truck out today for first time in a week. hadnt messed with 4 wheel drive in months, so locked in the hubs, went for a drive. came to a stop and put shifter in N and put truck in 4 lo. been awhile so I just pulled back on it kinda slow and got some grinding. So was messing with it. IF i pulled to the side and pack with some force it went smooth, but if I babied it from 4hi to 4lo it would grind and catch.

Is this normal? does it always need to be man handled with swift deliberate motion?
 
Stock 305cid, 700r and whatever the most common Tcase is. Im guessing gear driving from the sounds, dont think chain would do that. RPMs in neutral are around 700-800

which is the better setup - chain or gear
 
Gear is stronger but chain tcase is lower gears stock.

You have a 208 or a 241 depending on the year. The chain has nothing to do with there being a grinding theres still gears in there. The chain simply carries the power to the front output where a gear driven case has intermediate gears to carry the power over.
 
Its a 1984 K5.

So what about the grinding, is it just me? or an issue you think?
 
You were in neutral but when you shifted from low to high the transmission output shaft started to spin from friction in the clutch packs in the trans. Next time shift to park and then shift the transfer case.

I would stop shift to park and not let up on the brakes and shift the transfer case. If you let up on the brakes you could roll a small amount and "load" the transfer case putting pressure on the gears and making it hard to shift the transfer case.

I would not think that it is anything to worry about.
 
I did put in park once and it did it. I wonder if its a combo of my RPMs too high and just me not getting it in smoothly. I dont think there is anything wrong per se, but want to make sure of it. IF its just me than not a problem.
 
When I put the shifter into park and then tried 4hi to 4lo I got the same grinding. But I was pussyfooting with the trans shifter. I was moving it easy, not in a deliberate motion. But if I go quickly with one shift motion from 4hi to 4lo and vice versa it is fine. I know Im thinking too much about this, but I just want to make sure Im not missing something or there is something I need to address. Going to check fluids tomorrow and probably pull shifter cover and put some lithium grease (I know it has nothing to do with grinding, but couldnt hurt the shifter itself).
 
Any automatic transmission with no load on the output will spin the output shaft in neutral.
The only way gears can grind, is if they are moving.

The only thing that can move the gears, is either the transmission, or the wheels.

So, if you are in park, and the truck is not moving, then the gears should not grind no matter how slow or fast you shift.
The best way to shift into 4Lo, is to stop the truck, put the transmission in park, foot on the brake and shift.
However, there is often a problem with this. If you are stopped under a load, such as a hill, and the parking pawl is holding the truck, then you are going to have trouble getting the transfer case out of Hi.
In that case, you need to stop the truck with the brakes, shift the transmission into neutral, wait a second, and then into park without releasing the brakes. Then the transfer case should shift fine.

One thing you should not do, is shift the transfer case into neutral with the transmission in neutral with the engine running and then try to shift into park.

That is not good on the parking pawl. if you find yourself in that fix, the best thing to do is turn off the engine, shift into park, and restart.

Anytime you hear gears grinding, it is not good. Its just that there are different degrees of bad.

J.
 
What I always do on the trail because it is easiest and most reliable is this:

While rolling forward or back very slowly, toss the tranny in neutral and quickly put pressure on the t-case shifter in whatever direction you need it to go. Since you are rolling the wheel-side of the tcase slowly, the gears will mesh as long as you keep moderate pressure on the shifter. Never grinds the teeth this way and you won't run into a situation where you have to turn the engine off to put the tranny back in park. When you're in a tight trail, it is too much of a PITA to put it in park, pull forward, park again...until the gears mesh. If you've ever driven a manual without a clutch, it's the same concept. The clutch slips on our NV4500 at work, so rather than adding to the glazing from people slipping it too much, once I get going I just shift without the clutch. Once you get a feel for the gearing, just put some slight deliberate pressure on the shifter at the right speed, and you feel it pull the gear into place.

If you drive old auto-clutch 3 wheelers for a long time you'll get used to it and your brain will see it better. The little gears in the crankcase never mesh unless you're moving a little bit. I remember rocking the machines back and forth when I was about 5 or 6 while trying to climb over a stump that I didn't notice until I realized 2nd didn't have enough torque. That's a lot of sweat for a little 90 lb kid, so I learned to shift with the tires rolling.
 
In my '90 with a NP241 I always put the trans in neutral and shift straight through from 4 hi to 4 low fairly quickly. It will never grind doing it this way. If you go slow, or stop in the t-case neutral position, then it will always grind. I've even read factory owner's manuals that tells you to avoid stopping in neutral to avoid grinding.
 
It's your truck growling at you because you don't put it in four wheel drive enough.... Take it wheelin' more often and it won't be angry anymore.

BTW...x2 on most of the responses above. It shouldn't be an issue.
 
I can't get my t-case into 4lo if it is in park. After 40 years of shifting it into and out of, there is plenty of slop in the linkage, just push-pull until it goes. But do avoid any grinding, grinding bad!
 
my NP 241 always ground when shifting at a dead stop. I would shift trans to neutral and shift the T-case from high to low in a deliberate motion at 1-3 mph with much better results
 
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