Discussion in 'Transmission & Transfer Case' started by Giant Rock, Sep 30, 2020.
Can you point me in the direction of the manual? Did a search and wasn't able to find it.
Regarding 4H shifts, I go in and out of 4H at highway speeds all the time, and have done this forever. 208, 205...
Winter driving in BC on mountain highways as well as logging roads.
Getting into 4L with an automatic I need a full stop and then into neutral before I look for Low.
With my np205 and 4l80e I have to shut the truck off to get into 4 low from a stop without grinding (makes the same sound as if you put a moving truck into park while its moving if I try in neutral).
Ok I'll give that a try as well. So do you typically use the coast in neutral method then when you aren't already stopped to shift into 4L?
Yes, neutral. I’m sure you can shift 4h while moving, I’ve just never tried. I also go in reverse for 30 feet when shifting to/from 4wd and locking/unlocking hubs. I do all the anal retentive old man stuff that’s supposed to help stuff fully engage/disengage under low stress—all of which may be completely unnecessary.
I always did that with the oem auto hubs because someone told me that's how it's done. When I converted to Warn 20990 manual hubs I wasn't sure if backing was necessary so I called Warn's tech line. The guy that answered was like "What? Backing up?? (laughing) Nooo...that's very old school and completely unnecessary with our products."
@Giant Rock You are clearly concerned about the grinding. I understand that, but you are way overthinking this. As others have said, 4Lo is not what you needed at the time of you being stuck, and most four-wheeling can be done in 4Hi. My Jeep Cherokee can be shifted into 4Hi at any legal speed, of course it's not a GM product, but it will grind when shifting into 4Lo, and I have never thought twice about it. A slow roll or at a stop, shift into 4 and go.
From 1985 owner’s manual, NP208, but should be the same for NP241.
FYI, the grinding you are hearing is from the transmission input shaft free-turning which "cause and effect", as you shift into 4L, you pass thru neutral on the t/case which allows the output shaft of the transmission to free-turn as there is no resistance on it, this allows the t/case input shaft to turn-freely. The gears are not lined up as it was in 2H/4H and you hear the grinding of the t/case gears.
You can shift into 4L with the transmission in park, but you may need to jerk it into gear as the free movement of the gears is now stopped.
Neutral is the lesser of 2 evils.
In newer vehicles with the push button 4WD, you get a clunk when it engages 4L as the gears align themselves.
That's what I have always done wit hall of my vehicles as well. The only time I've ever had gear grinding is if you stop in neutral... you need to firmly but smoothly push it right past neutral.
In a nut shell GM is telling you if you want low range just jam her in there. No slow or half stroking. Just go for the money shot.... Oh and welcome by the way!
Dude thanks so much posting this and thanks to everyone who commented. Just went for a test drive and it seems that the main thing is to:
1. Stop 2. Put truck in Neutral 3. Shift the 4x4 lever in one swift motion all the way to 4L. Worked perfectly.
Also I am taking the advice that for most stuff I really just need to pop into 4Hi and reserve 4L for hill climbs or if someone needs to be pulled out I guess. In any case, this noob got a little more educated today, thanks for that!
Suburban Sunset by Giant Rock posted Sep 30, 2020 at 6:24 PM
My NP208 I always put in neutral, find flat ground, stop, put in 4lo or 4hi, put in gear and go, if im changing between them i might just clutch in(same function as neutral in this case i think) and always try to do it still. Ive not attempted to do it while moving, the amount of gear multiplying 4lo does in 1st gear(not even Low granny gear) is enough to make sure to clutch in carefully so i dont buck it!. 4hi is pretty forgiving to me shift wise.
208 and 241 can be shifted from 2hi to 4hi any speed and back.
Make sure hubs are locked first. Not pretty if shifting at speed with unlocked hubs.
Idk about auto hubs, speaking for manual hub
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