73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: westsidek20 on October 02, 2010, 12:07:54 pm
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Hello to all ;D my first post, my first 73-87 truck ;) , mine is a K20 with V8 350, th400 and a NP 203.
What is the proper way of driving the truck? i know the NP 203 is a fulltime 4wd, while driving on the road and highway, does my NP203 has to be in "N" with unlocked hubs? and actually this is my first 4x4, so I'm really new with all of this.
Any info will be appreciated, thanks.
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Unless someone has updated the truck 203s never had hubs.
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The 203 is set up like this
l(lock)
L(unlock)
N
H(unlock)
H(lock)
You wana drive it in h(unlock) if you have it there and your hubs are unlocked also and you still move you have a part time kit installed which is a good thing keep it like that saves gas and puts all the power to the rear. If you ha e it in h(unlocked ) and your hubs are unlocked it hush means you don't have a part time kit installed and you have to lock your hubs the power will go to the wheels with least resistance not goodbif your in the mud then you want it to be locked. Most time if someone put manual hubs on they also went with the part time kit
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I have the same thing going on, this is very helpful... you guys know your trucks.
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Thank you very much Irish,
Alright, I tried it and i can drive in H unlock, and it actually moves on both H and H(loc) unlocked... i will keep it on H unlocked as you mentioned. So this means i have a part time kit ?? The only time when it doesnt move is on N.
I can really feal the diference in power when its on 4wd in the L's (locked).
Also i have a hard time shifting to the L's and N. What do i do to shift? im probably doing something wrong.
I shift in Park with the hubs locked, should i do it in neutral with hubs unlocked ??
???
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I have a stick and I push in the clutch and then shift. So shift in neutral or park never in gear. Does it move in h lock and unlock with the hubs unlocked. If so then yes you have the kit
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Lucky me, yes it moves in both H's.
If only i could take of as fast as i do with the 4wd "L" on... i have been reading about maybe changing gears, right now i have a 14 bolt FF rear axel, since i know somebody has already made some mod's to the truck (locking hubs and tcase kit) i dont know whats in the truck. What would be a good gear to have, i would like to be able to take of faster and burn some rubber (it has 33 X 12.50 X 16.5 tires) and how can i ID the existing gears??
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Remove the cover and count the teeth or read the stamp on the ring gear. Ring gear teeth/pinion teeth=____:1 ratio
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If you want to spin. Put it in granny and punch it i spun my 38s once on dry pavement don't like doing it cause its hard on everything I have 4.10s so you should have a lower ratio but since you have a 400 if you want to spin them and it wont do it that easy you might not want to unless you do put it in low since something has to take the stress of turning that rubber
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Sorry to butt in, Irish if I am reading this right, if your hubs are unlocked and truck started, if you can move between h(locked) and h(unlocked) then you have a part time kit. So if you do the the same thing and you can not switch between the 2 h's that means you do not have the part time kit installed on a np203 ?
I have been wondering how to check this for awhile, thanks for any replies.....
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Um what lol. You can't shift from h unlocked and h locked with the truck in park or neutral
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If you want to spin. Put it in granny and punch it i spun my 38s once on dry pavement don't like doing it cause its hard on everything I have 4.10s so you should have a lower ratio but since you have a 400 if you want to spin them and it wont do it that easy you might not want to unless you do put it in low since something has to take the stress of turning that rubber
Lost me there, didn't get all of it. what does "put it in granny" mean? and a 4.10 on the 400th is not a good idea?
Sorry for the delayed questions, i had family visiting and took all my time LOL
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On my sm465 I have a low gear only need it when I'm towing sometimes when I'm taking off. Not saying your setup is bad but when you try tp turn alot of rubber something is going to give (transmission or the rear) guess what I'm trying tp say is if you keep turning all that rubber something eventually will give up
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I get you, im not a racer, and i dont show off (tires are expensive also), its just that my truck seems to be somewhat sluggish and i would like to take of faster, when i step on it, its no way close to burning rubber. I just wanted some pointers because my truck has the 350 on it and everybody just tells me "well it should have enough power to really get you moving"... just want to know what would be a good upgrade ;)
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Think about this my 350 in my 86 same one in my 79 now but it the 86 she only had to turn 30s but she would struggle to turn them unless the pavement was wet or the tread was almost gone. In the 79 she will spin no problem when I take off. Its all about gearing so with 4.10s she should be able to spin even if you had a v6 in it maybe timing is off maybe trans isn’t in low gear not sure but it doesn’t sound about right
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I get it, its just that i had the idea that i needed to upgrade the 350 to have more power (just looking for an excuse) ;D
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Just because its a 350 doesn't mean its a powerhouse. Large combustion chambers low compression ratio and peanut cams!
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After re-reading the thread it sounds like you should really investigate what gear ratio you have. You mentioned that it feels like it has more get up and go in 'L' which is a result of the gear reduction from the t-case. If you find that you have a really high (low numerically) gear ratio with the tires that you are running then swapping gears may be the ticket. Also, like screamin86 said, a 350 is not inherently a go-fast machine. Alot of cheap and easy upgrades, not to mention just a thorough tune-up can make a world of difference. If you are just looking for an excuse to upgrade, well, those are easy to find ;D
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alright, i know i have to figure out my gear ratio, i haven't gotten to that, but i will probably do it this weekend. Quick reference, i need RTV and two bottles of gear oil, right? Do i have to torque the screws? its a 14 bolt FF rear.
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I like to use black RTV, and I don't torque the bolts. I usually snug them enough to squish the silicone, and come back in an hour and tighten them down. I would bet on closer to 3 or more quarts for a 14 bolt, and fill it til it runs out the hole.
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I will try it your way and post results next week. ;)
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UPDATE...
So i knock the lid, to figure out the gear ratio by counting the ring and pinion when i get this surprise...
I saw some other post, that said its a Gov-Loc? is that true?
Finnally since i dont have any real knowledge and skills, i ended up putting the lid back on, Result: i couldnt count the pinion so i ended up not knowing the gear ratio, just a new question about the rear axel.
Can anybody give me some info about it?
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You didn't see any numbers stamped on the side of the ring gear or the top of the pinion?
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No i didn't, rookie mistake i guess. :P
When i saw the "GovLoc" (not sure if its actually one) i didn't know what to do, Don't have the experience to take out the locker to be able to see the pinion, so i should take out the front one that should have the same gear ratio as the rear (right?) or am i going to stumble at another locker at the front?
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The front is or should be the same gear but the front shouldn't have a locker unless someone added it!
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Check the stamp on the ring gear. It will be something like 40:13, etc. If you have been using 4wd without a problem it's a safe bet that the front and rear are the same. I have seen mismatched pairs before, so you never know what you're going to get after a few previous owners have their way with it. Bonus points for the Gov-loc
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Here is some extra info i looked up... don't know if its helpfull for the community.
http://dyeager535.topcities.com/posipictures.html
It explains how it works and has the diagram ;D
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another way to check the ratio is to lift one tire, put it in neutral, ( block the other tires) and rotate the wheel as you count the number of revolutions the drive shaft makes One revolution of the tire is one revolution of the ring gear so you will count the pinion revolutions.
Also, the larger tires will effectively reduce the torque to the pavement over smaller or stock sizes. That will affect your acceleration.
Hope this helps.