Author Topic: Feels like something is stuck/binding when I start to roll forward/reverse  (Read 3978 times)

Offline mehl871

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Hey guys,

So before I start, let me just put it out there that I am a certified newb, not just on here but when it comes to my old truck. I have a 78 K10 scottsdale that I picked up about 6 months ago. It has a 350 and th350, also a 203 transfer case. Im just starting to dive into its issues, which havent been too bad i can say, especially for a ranch truck thats been sitting a few years.

So to make a long story short, ive noticed with the last couple times Ive backed it out of my garage onto the driveway, it seems to be binding up or getting stuck somewhere when its just rolling. By that i mean if i take my foot off the brake when its in gear (forward or reverse) it wont even roll by itself. Even with being on the slight incline of my driveway its not rolling backwards. I will even put it in nuetral, both on the trans shifter and the floor shifter for the TC. Nothing. Feels like when I try to go forward up my driveway, i have to get on the gas a little and it will roll but just doesnt roll freely like it should, when i take my foot off the gas it stops and wont roll back. Like something is locked. Which i thought well maybe it has to do with the LOC in the TC because it is in H LOC all the time. Was that way when i got it and if i try to shift into H,N,L or L Loc it just makes a grinding noise and i can see the front output shaft spinning by itself when the truck is just sitting still. Also, ive taken this truck around the block a handful of times since ive had it and its never had this binding problem before, in fact it doesnt bind or anything going around a turn being in H LOC which lead me to believe theres something wrong with the TC. I did notice it a little when i backed it out last week before i replaced the rear output shaft seal. Changed the oil in the TC and backed it out today and its still doing it but seems worse like something is dry or not lubricated. Iv been trying to brush up my knowledge on this transfer case and how everything works but i figured id try my luck on here. I should also add that its to the point where im afraid to actually try and drive it I feel like something is going to break. It actually spins the tire(s) ( i can see the left rear spinning cant tell if the right rear is or not) when i get into my garage and it gets on the smooth garage floor, and im just barely giving it any gas.

What is the proper way of shifting the transfer case through the gears?

 Ive read before about the grinding noise, when you try to shift into the other gears (L,N,H, Locs) that it needs to be in park and the grinding noise is coming from the transmission trying to engage a parking prawl?? Its hard to know whos right and wrong on the internet lol


Hope that makes some sense!

any help is appreciated, thank you

« Last Edit: February 13, 2018, 11:36:35 PM by mehl871 »

Offline Irish_Alley

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #1 on: February 14, 2018, 02:51:30 AM »
ok lets start of with the t case. you have to be in park or neutral when changing the transfer case's gears. the grinding noise you hear is because when you take the t case out of gear and the transmission is still in a gear the guts of the transmission are turning due to nothing holding them back like brakes or any resistance. this is normal operation nothing to worry about if im understanding you correct. and about the front driveshaft moving, idk what to tell you but on my 79 k20 with a sm465 (manual trans) and np205 it would do the same thing if i took the transfer case out of gear while sitting.

about the truck not moving or taking gas to move sounds like a brake hose or caliper is restricted and activity "locking" that wheel up. it should release itself over some time when you release the brakes but again it might not. to test this jack the front end up off the ground and have a helper press the brakes then release then try to turn the front wheels by hand and see what it does. my bet is you probably wont be able to turn that one by hand. on a 2wd i would lean to the brake hose and the metal clip on the hose, the clip can rust and restrict flow of fluid on a 4wd its kind of a toss up one way to tell is if you found the stuck wheel undo the brake hose at the caliper and see what it does. if it unlocks it could be the hose if it doesnt it could be the caliper
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Offline Jason S

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #2 on: February 14, 2018, 03:17:43 AM »
Welcome from Kansas

There's a few things to check before completely faulting the transfer case.  Also, there are several items that need investigation to get some information on your NP-203.

Quote
if i take my foot off the brake when its in gear (forward or reverse) it wont even roll by itself.
After a brief read of your situation - Keeping in mind it's a pretty heavy truck - Have you checked the brakes to ensure each wheel is only slightly dragging?  If a front caliper piston is slightly cocked in its' bore or rear shoe(s) are adjusted too tight, the truck might not roll freely. With Transfer Case in Neutral (N) and transmission in neutral the truck ought to be able to roll some (should be able to hand push on level ground).

Quote
in fact it doesnt bind or anything going around a turn being in H LOC which lead me to believe theres something wrong with the TC
Are there manual locking hubs on front?  Do you know if a part time conversion was installed in the transfer case?  If manual hubs and a part time conversion was NOT installed, the truck would only move in Hi-Loc or Lo-Loc. 

The NP203 in factory form had Lo-Loc, Lo, Neutral, Hi and Hi-Loc.  There is a differential in the transfer case that works like an open differential in an axle and send power through the drive shaft to the axle with least traction.  Several companies have offered a part time conversion over the years that essentially locked the transfer case differential. This made the NP-203 operate like a part time transfer case for better fuel economy (in theory).  In Loc postion, the transfer case sent equal power to both driveshafts.

With the part time conversion in the NP-203, Lo-Loc would power the front and rear output shafts equally, after gear reduction. Lo position sends power only to the rear after gear reduction.  Neutral disengages the power to both front and rear drive shafts. Hi sends power directly to the rear drive shaft without transfer case gear reduction.  Hi-Loc will send power equally to front and rear driveshaft.

Sometimes people installed manual locking hubs on the front axle, turned the dial to 'Free' and then ran the unconverted  (i.e., non-part time kit converted) NP-203 in Hi-Loc to circumvent the full time operation.

Quote
Changed the oil in the TC and backed it out today and its still doing it but seems worse like something is dry or not lubricated
 
What oil did you put back in to the transfer case?


Quote
the grinding noise, when you try to shift into the other gears (L,N,H, Locs) that it needs to be in park and the grinding noise is coming from the transmission trying to engage a parking prawl

Transfer case should shift on the fly between Hi and Hi-Loc and back.  Going to lower gears (Lo and Lo-Loc) ought to be engaged from a stop; not rolling from Hi into Lo. Then Lo-Loc to Lo and back should be on the fly.

EDIT:  Appears Irish posted as I was typing...
« Last Edit: February 14, 2018, 03:21:16 AM by Jason S »
1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"

Offline Rapid Roy

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #3 on: February 14, 2018, 06:16:08 AM »
Welcome
1974 Cheyenne 10 LWB STOCK 350 W HEI /TH350/AC/4 BBL Quadrajet
Mopar by Birth
Chevy by Choice

Offline mehl871

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #4 on: February 14, 2018, 08:54:55 PM »
Makes perfect sense about it possibly being a brake/hose issue. Especially with the back tires spinning on the garage floor when im trying to pull it in. So, i had a few minutes today at lunch and I wanted to know so I jacked it up and had someone press the brakes and let off. The front driver side spins freely, has minor resistance. The passenger side def. has some resistance, and is not easy to turn. Didnt have time to get into it at lunch obviously, but im going to try and take a look tonight. Good to know about the front drive shaft spinning also.

I put 10w-30 in the transfer case. Doesnt have manual locking hubs, nor has it been converted to part-time as I know of. The guy I got it from has zero information on it other than the engine size. Everything looks pretty original underneath, but im not really sure what to look for if there is any sign you can tell from the outside if its been converted?

So if i shift the transfer case into L or L-Loc at a stop in PARK or NUETRAL it shouldnt be making any grinding noise or any kind of sound right? should just go into gear?


thank you all for the expertise and the info on how to shift the transfer case the right way, much appreciated!


Offline Irish_Alley

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #5 on: February 15, 2018, 03:25:03 PM »
ive had the front lock up to the point where i couldnt turn the tire by hand. there shouldnt really be any resistance if you try to turn the wheel by hand. your good on the 10-30 for the np203
if you shift from H or hi loc to L or L loc you shouldnt hear any grinding if it goes in gear if your in park and neutral if youve come to a complete stop. you may have to rock the truck a little to get the gears to match up but nothing should be turning inside to grind
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Offline Jason S

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Re: Feels like something is stuck/binding when I start to roll forward/reverse
« Reply #6 on: February 15, 2018, 07:45:31 PM »
Quote
Everything looks pretty original underneath, but im not really sure what to look for if there is any sign you can tell from the outside if its been converted?

No outward signs if a kit has been installed. The part time kit installs inside the rear extension housing on the back of the transfer case.

Presence of manual locking hubs doesn't always mean a kit was installed either.  Transfer case operation would show if there is a part time kit.

Mile Marker still offers part time kits. It locks the differential in the t-case for part time operation. At one time they also offered a shaft kit that completely replaced the t-case differential, but was discontinued several years ago.  Whether or not to convert a NP-203  is a matter of opinion.
1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"