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Couple quick questions.

chevy4x4power

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Clemson/Oburg
1978 gmc jimmy, np203, th350, 350 engine

1. I understand what hi and hi loc as well as lo and loc do in terms of 4WD, but what about when you put it in neutral.

2. My shifter will only go in lo and lo loc as well as neutral (i believe its in it), I've been reading that they can get stuck since there exposed to the elements. What is the process for getting the shifter and linkage out and cleaning it?

3. My oil pressure light is stuck on 60, its maxed out. How do i fix this?

4. Finally, my rear window won't roll down and as a result i cannot get the darn tailgate open. It's got the button upfront for it, bad switch maybe?

Thanks yawl for the help!! Merry Christmas!
 
First off, neutral on the tcase is like truly putting the truck in neutral, so even if you put the tranny in gear, the truck won't go no where. Second, All I can say about a stuck shifter is that the one time I have had an experience with them was when my buddy's bronco was stuck in 4 lo. PB blaster and manhandling it were the fix, don't be afraid to put some muscle into it. Third, the electric tailgate windows on these trucks are notorious for going bad, I recommend converting to a manual rear window, but as far as it not working, check the easy stuff first, the fuse... If it's bad, replace it, if it's good, start tracing wires, take a test light and check for power to the switch and if that checks out good then check for power from the switch to the motor. You should be able to find your problem pretty quickly doing that. Hope I've helped you out a little, I'm sure some one else will chime in and cover anything I've missed. Good luck with the truck and merry Christmas.
 
And as far as the oil pressure gauge, it's mechanical, at least the one in my 76 is... The only way I can see a mechanical gauge failing is a clogged sender or the tube that runs to the back of the switch could be clogged. Or another thing to consider is that the ideal oil pressure of a chevy 350 is 60... It could be reading accurately.
 
4. Finally, my rear window won't roll down and as a result i cannot get the darn tailgate open. It's got the button upfront for it, bad switch maybe?

There's a safety switch on the inside of the gate that makes contact when the gate is closed and it's notorious for going bad. It's on the driver's side by the latch. You can lower the window by unscrewing the access panel and disconnecting the large cable from the motor. Hook a drill to the cable and lower your window.
Also, if you live in a rust prone area then you may have another common electrical issue. The ground for the window motor goes through the tailgate hinges/bolts and if there is corrosion/rust under the hinges then the ground path is broken. Best solution (and not a bad idea even if it's not the issue) is to run a dedicated ground wire from the frame to the case of motor. Ground for the motor is the case itself, the two wires going to the motor are both power, apply power to one wire makes it go up, the other makes it go down.
 
Thanks for the replies guys.

Got the shifter freed up some thanks to wd40 and pb blaster. Hopefully ill be able to get it all the way down with some more wd and pb!

As for the window...which fuse corresponds to the rear window? I didn't find one clearly marked.

What exactly do you mean, "hook a drill to the cable?"
 
One other thing that can happen with that cable,is the shaft can rust inside its plastic sheathing,that happened with mine,easy fix ,just replace the cable,I discovered how badly rusted when I took the cable off the motor and tried to drive it with a drill motor ,and it still didn't work
 
What exactly do you mean, "hook a drill to the cable?"

Unscrew the cable (circled in blue) from the connection at the motor (circled in red). There's a square cable inside that's about 3/4" long that you can put in the chuck of your drill to act as the window motor. And when the gate is down and you 'raise' the window, make sure you support it when it's about half way out so you don't break the window - they are very heavy.

windowmotorcable_zps1bab47aa.jpg


As a side note, that cable goes to the window transmission (you can see that behind the window on the passenger side) which sometimes has a plastic gear that breaks but you can hear that. If when you try to operate the motor via the window switch and you hear the window motor try to operate then the wiring is good and it's a mechanical issue - no noise then there's an electrical issue. Don't be so hasty as to blame the motor, it's usually something else and I don't think anyone sells those (could be wrong). But the window motors are very simple to disassemble and fix.
 
Unscrew the cable (circled in blue) from the connection at the motor (circled in red). There's a square cable inside that's about 3/4" long that you can put in the chuck of your drill to act as the window motor. And when the gate is down and you 'raise' the window, make sure you support it when it's about half way out so you don't break the window - they are very heavy.

windowmotorcable_zps1bab47aa.jpg


As a side note, that cable goes to the window transmission (you can see that behind the window on the passenger side) which sometimes has a plastic gear that breaks but you can hear that. If when you try to operate the motor via the window switch and you hear the window motor try to operate then the wiring is good and it's a mechanical issue - no noise then there's an electrical issue. Don't be so hasty as to blame the motor, it's usually something else and I don't think anyone sells those (could be wrong). But the window motors are very simple to disassemble and fix.

Thank you sir for the picture!!! I love k5's, I'm trying to fix this one up and get it right. My mechanical knowledge is very limited, I'm kind of slow on grasping some of the stuff y'all say. Thanks for the patience.

I'm going to tackle this after i get my 24 inch light bar put on my silverado!

As for the brakes... They are really spongy. What should i tackle first to try and solve this?
 
For the brakes you should first try bleeding them to see if you can get any air out of the lines that might have gotten in there from sitting. Another cause of spongy brakes could be you booster, to check to see if it is good you need to run the truck for a while than without touching the brake pedal just turn the motor off, wait 15 mins than go and pump the brake pedal a few times, you should get 2-3 good, power assisted pumps before the pedal goes hard. If you don't, the booster is bad.
 
On the ground is fine just make sure wheel is blocked and get all air out

Good deal, what does the bleeder thing look like?

From what i've read, i work from the driver side then go back pass. side then front passenger then front driver.

I should get a piece of tube run that from bleeder to a drink container with some brake fluid in it.

Crack bleeder thing, get person to pump brakes 2-3 times or until clear brake fluid comes out. Then get them to hold break down while i tighten bleeder nut.

Rinse and repeat while making sure master cylinder doesn't run low on brake fluid .


Sorry yall I'm a newb i know
 
With a helper:

1. Helper pumps brake pedal until pedal is firm
2. Helper holds pressure on pedal and tells you it is ready
3. You open bleeder and let fluid/air out (pedal goes to floor and helper continues to hold it there)
4. Close bleeder
5. Tell helper you are ready
6. Repeat

If the helper lets off of the pedal before you close the bleeder, it will suck air back into the system and you will have to restart.
 
I just get few bottles of brake fluid and fill master cylinder first. Then get 2nd person to pump brakes and hold pedal then crack right rear first and bleed till no air bubbles then move to left rear,right front and left front last. You can use hose on bleeder screws for fluid to go in catch can. Check master after rear wheels and front don't let it run dry. Just back yard way of doing it. Check pedal when done repeat if needed.
 
Also get helper to say floor when he feels pedal drop all way down so you done get air in system
 
Save yourself and helper the headache and build a one person power bleeder for $10-$20. Gets the air out much better and quicker and did I mention it makes it a one person job. Some people use the vacuum off the engine but I prefer my pressure bleeder similar to the one this guy has:

https://www.youtube.com/watch?v=U456sLceKp0

And yes, you work from the wheel farthest from the master cylinder to the closest. So that would be one of the rear wheels since they should be the same distance from the mc, then the pass. front, then driver front.
 
Bleeders are nice got one for work but if in a jam 2 man works just fine if you work together well in communication area.
 
Back on the topic of the t-case shifter, I just messed with mine, and sure enough the outter linkage rod adjuster nuts were loose and had backed way off. Re-adjusting really helped smooth out range selection.
 
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