TH350 will not engage after sitting for three months

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Cipriano

Junior Member
Joined
May 25, 2026
Posts
16
Reaction score
23
Location
SW USA
First Name
Nathan
Truck Year
1976
Truck Model
Sierra
Engine Size
350
Well, I had some time to tinker with it tonight. It needed 1 1/2 quarts but that didn't help. I can push it forward whether the truck is in neutral OR in park! That's not right.

I also engaged and unengaged the hubs that didn't make a difference. Also at the extreme left of the shifters position (park and a tiny bit more,) i get a growling from tranny area.

Thanks for any ideas
 

Radiohead

That guy on the Columbia
Joined
Mar 17, 2022
Posts
3,108
Reaction score
10,081
Location
Low Earth Orbit where it's safer
First Name
Eric
Truck Year
MCMLXXIX
Truck Model
C-20 Silverado Camper Special
Engine Size
454 crazy cubes, or 7.4 luscious litres
A shifter forks issue or if it has one, a chain problem. Something like that.
I don't know enough to be terribly specific, but gut says something dumb like this.
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,272
Reaction score
44,207
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Well, I had some time to tinker with it tonight. It needed 1 1/2 quarts but that didn't help. I can push it forward whether the truck is in neutral OR in park! That's not right.

I also engaged and unengaged the hubs that didn't make a difference. Also at the extreme left of the shifters position (park and a tiny bit more,) i get a growling from tranny area.

Thanks for any ideas

Ok, so you have selectable hubs. Were they unlocked when the truck was towed from behind?
 

Smtty58

Junior Member
Joined
Mar 19, 2026
Posts
26
Reaction score
25
Location
Mass.
First Name
Lyle
Truck Year
1990
Truck Model
R3500 Crewcab
Engine Size
350
Selectable hubs? Did somebody try to do a part-time conversion? Consider opening the Tcase so you know what you have.
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,272
Reaction score
44,207
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Selectable hubs? Did somebody try to do a part-time conversion? Consider opening the Tcase so you know what you have.

It would be simpler to just figure out which shafts are engaged in each position.
 

Cipriano

Junior Member
Joined
May 25, 2026
Posts
16
Reaction score
23
Location
SW USA
First Name
Nathan
Truck Year
1976
Truck Model
Sierra
Engine Size
350
Alright, I got it moving! I disengaged hubs, put column shifter in neutral, transfer case in 4low and started it up. What was throwing me off was the column indicator isn't lining up properly. Neutral isn't neutral. Reverse is 3/4 of the way to reverse and reverse is neutral. Neutral begins the drive settings. I think a non-pro installed this TH350!
 

Turbo4whl

Full Access Member
Joined
Oct 30, 2019
Posts
4,069
Reaction score
10,325
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
Simple fix now. The shift indicater needs to be adjusted. Small cable pulls it when you rotate the shift lever. The collar of shifter near the dash, there is a screw on the right side of the collar where the cable is attached. It pulls the cable to move the indicater. Loosen the screw, move it to have the pointer line up. Use neutral to line it up.
Someone should have a picture for you.
 

Turbo4whl

Full Access Member
Joined
Oct 30, 2019
Posts
4,069
Reaction score
10,325
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
I should add, you need to take off the small bottom piece of the plastic dash to see the screw. Don't touch the little pointer with your finger. The dry plastic pointer will break off if you breathe on it.
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,272
Reaction score
44,207
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The linkage itself could be out of adjustment too. That's also a very simple adjustment to make, with just a single pinch bolt on the linkage rod.

If you break the pointer on accident, I "know a guy" with several NOS replacements.
 

425HP409

Supporting Member
Supporting Member
Joined
Jun 16, 2026
Posts
6
Reaction score
3
Location
TX
First Name
Charles
Truck Year
1968
Truck Model
C10 Short Wide
Engine Size
396
It was towed to my house, rear axle elevated, front axel on ground. Could that have done something?
that should not have caused any problem. I am leaning to fluid level.
 

Forum statistics

Threads
48,527
Posts
1,070,309
Members
43,023
Latest member
donkdonk
Top