New GMC Owner with shifting troubles

[DoubleDingo]

Looks very accessible to me

 

[cornholeeo]

Thanks for the tip!

Just added another 2L (all the store had) and not much is showing up on the dipstick (idling hot in park).

Now my head has been turned in another direction. After shutting her off and trying to turn the engine over, nothing. No cranking or anything. I’m wondering if my alternator is causing the root of the problem. I cant see any other reasons as to why it wouldn’t crank after about 15 mins of idling.

(For context I keep my batteries negative thermal disconnected because I’m still unsure if I have a parasitic draw (separate issue))

To check parasetic draw, with neg. disconnected, everything shut off. Use 12v test light. One end to battery and the other to cable. If it glows you have a draw. If it doesnt light, youre good. Well unless your battery is already dead.
For the tranny normaly when adding fluid you dont need to drive it.Just shift to reverse and down to 1st and back to park a couple times, then recheck.

 

[cornholeeo]

Replaced all my fuses a while ago, there shouldn’t be any fuses causing a draw. Most of them were blown.

I don’t think a parasitic draw would’ve caused my battery to die after 15mins of idling

Not sure if you said you checked the battery voltage after it wouldnt start. If it was good, hot or bad starting relay could be the fault.

 

[WhosCacti]

Hello squarebody community!

I'm new to the world of 80s tech/ vehicles, but I'm eager to learn the workings!
I've been working on my 1981 GMC G3500 5.7L V8 for about 8 or 9 months. Over the winter I had it stationary and parked so it hasn't been engaged with or running for a while.

The past couple days I finally decided to get it over with and did a full service (new radiator hose, trans filter +gasket, new battery, oil change, etc..). The dash needed to be put together (adding an updated stereo system), as it was left unassembled for quite a few months. It took some time trying to understand where everything needed to be plugged in, but I got most* of the important stuff sorted.. With that being said I gave her the first start since the beginning of winter - it took some cranking but she started up!

Now before the winter she was driving and shifting just fine, a little clunky when going into gear, but while driving my shifts felt fine! However, when I started her up and tried to shift in gear I noticed that I didn't need to press the brake peddle in order to shift into gear; and when in gear no amount of revving would get the wheels rolling.. She seems to be stuck in park. After some research I have a feeling that it might be my shifting cable, but I'm not sure what to look for or how to aid this ailment.
I do also want to mention that I filled the transmission with about 1.5L of the correct trans oil, but nothing is showing on my dipstick - (yes I am checking while the engine is running). Is it still just too low on oil, and could this be the reason for not going into gear?

Thank you for your help, and hopefully we can get her moving again - I'm very eager to give her a nice long drive!

Hi everyone!

Exciting news! Firstly I wanted to thank everyone for their tips/ help. As for the vehicle: Once about 7.5L of fluid was added the transmission went back into gear. As for the power issue the findings were: break light switch wasn’t attached to the bracket and was keeping the lights on. Alternator was replaced just to make sure, now power issues have almost been sorted.

First drive was to the car wash and felt. Transmission is smoother than my current daily driver. Up a steep hill flooring it gave me about 40 kms/hr (max). The was went pretty great, but the previous owner beat up the paint/ window seals pretty good. (There’s silicone, and rust spots everywhere.)

There’s still so much TLC this GMC needs, and deserves. But I will be doing more updating as they come.
8 months ago I started this project, and if you want to watch the process I documented the process since the beginning and you can watch it here:

xc_hide_links_from_guests_guests_error_hide_media

I’ve attached some photos of the truck after the car wash below.

Again thank you all for the tips.. glad I didn’t have to take the front end off lol!

 

[Ricko1966]

Take a blown blade-type fuse and solder a 194 (dash light) to the terminals.
With the battery hooked up, and ignition OFF, pull each fuse one-by one and replace it
with your new tester.
If the bulb glows; even slightly, you've found the circuit that is causing you parasitic draw.
If it doesn't glow, you're good. Move to the next fuse.

Like this, this has been my go to for years. But first step clean all battery terminals and battery cable connections,charge the battery and load test it. Crude load test would be fully charged battery , turn on all the lights radio and heater motor ,
with a volt meter attached to battery see if battery voltage drops below 10 volts in 10 seconds. If it passes pull the negative battery cable clip a test light to the negative battery post,hook the other end to the disconnected cable if the light is on disconnect the alternator wires. Is the light out? Replace the alternator. If the light didn't go out start pulling fuses with the test light still attached until you find the fuse that puts out the light.Reattch your battery cable. Now just like snoots said put the 194 bulb in place of the fuse and disconnect everything on that fuse circuit one at a time, the one that turns the light off is your problem.

 

[Snoots]

Hi everyone!

Exciting news! Firstly I wanted to thank everyone for their tips/ help. As for the vehicle: Once about 7.5L of fluid was added the transmission went back into gear. As for the power issue the findings were: break light switch wasn’t attached to the bracket and was keeping the lights on. Alternator was replaced just to make sure, now power issues have almost been sorted.

First drive was to the car wash and felt. Transmission is smoother than my current daily driver. Up a steep hill flooring it gave me about 40 kms/hr (max). The was went pretty great, but the previous owner beat up the paint/ window seals pretty good. (There’s silicone, and rust spots everywhere.)

There’s still so much TLC this GMC needs, and deserves. But I will be doing more updating as they come.
8 months ago I started this project, and if you want to watch the process I documented the process since the beginning and you can watch it here:

xc_hide_links_from_guests_guests_error_hide_media

I’ve attached some photos of the truck after the car wash below.

Again thank you all for the tips.. glad I didn’t have to take the front end off lol!

Way cool ride! Glad you got it fixed and can now enjoy it.
What percent grade is that hill and how many miles are there on the engine? Sounds like a basic tune up is needed.

 

[WhosCacti]

Way cool ride! Glad you got it fixed and can now enjoy it.
What percent grade is that hill and how many miles are there on the engine? Sounds like a basic tune up is needed.

The hills grade is about 12% on average, and the engine has about 70,000kms on it

 

[Snoots]

I'd say a basic tune up then. It shouldn't be lugging that slow. Unless you're hauling a trailer.

 

[DoubleDingo]

I'd say a basic tune up then. It shouldn't be lugging that slow. Unless you're hauling a trailer.

12% grade is very steep.

Edit: Did the conversion, 25mph is very slow, but on a steep 12% grade, sounds about right. Second or first gear and engine roaring