Transmission overfull

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.

American_justice

Junior Member
Joined
Jul 9, 2019
Posts
12
Reaction score
2
Location
Kerrville tx
First Name
Levi
Truck Year
1983
Truck Model
C10
Engine Size
350
So I just did a th350 swap on my 83 c10. I had it right on the 'full hot' line when I was filling it up while it was running in park. I checked it several times and it seemed good. I took it for a spin around the block and parked it and checked it again and it read about a 1/4 in over the full hot line. Ive heard it is bad to overfill ur tranny, I'm wondering if I should be concerned about it being a lil overfull like that. I'm most likely overthinking it but I'd like a second option. Any info is appreciated, thanks in advance.
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,128
Reaction score
9,299
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
IF that's all it is over, don't sweat it on a Turbo 350 or Turbo 400. Both are very forgiving, and even run a little low, they're good. If in the event it is to much there is a breather vent and it will foam up and spill itself out if it needs to but I think you'll be just fine.
 

Shorty81

Baby Boomer
Joined
Mar 19, 2018
Posts
3,102
Reaction score
5,778
Location
North West ohio
First Name
Darren
Truck Year
86
Truck Model
K20
Engine Size
496
IF that's all it is over, don't sweat it on a Turbo 350 or Turbo 400. Both are very forgiving, and even run a little low, they're good. If in the event it is to much there is a breather vent and it will foam up and spill itself out if it needs to but I think you'll be just fine.
X2
 

shiftpro

Full Access Member
Joined
Aug 31, 2012
Posts
4,855
Reaction score
6,092
Location
BC Canada
First Name
shiftpro
Truck Year
73-87
Truck Model
1500, 2500, 3500
Engine Size
350, 383, 454, 496!
It's the newer auto trannys. Notice they have cam locks on the dipstick tube. If tranny goes bad OR is overfilled, it shoots out the dipstick tube. Hot manifolds ignite trann oil, and this is the most difficult bugger of a fire to deal with. Usually car burns down. So if you want to pull an insurance fire scam, don't use a leaky carb/gasoline fire.
 

American_justice

Junior Member
Joined
Jul 9, 2019
Posts
12
Reaction score
2
Location
Kerrville tx
First Name
Levi
Truck Year
1983
Truck Model
C10
Engine Size
350
I appreciate the feedback. Yea its only a lil over, I watched it pretty closely as I filled it up. It was just about a 1/4 in over after I took it for a spin. I think it'll be fine. Nothing's come spitting up out of the dipstick so that seems good
 

73c20jim

Full Access Member
Joined
Jun 11, 2018
Posts
2,282
Reaction score
2,926
Location
Tombstone, AZ
First Name
Jim
Truck Year
1973, 1973
Truck Model
C20 2WD Custom Deluxe. C10 2WD Base Model
Engine Size
350 CID 195/260 HP Goodwrench crate, 400 CID 2bbl
Was fluid at operating temp when you filled it?? If not when it gets hot the reading will change.
 

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
10,041
Reaction score
10,134
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
I dunno...I run mine below the full mark and quite frankly my transmission being left KNOWINGLY overfull would...keep me up at night. No freakin way in hell would I allow that to slide. Hay, just sayin.

If you decide that some fluid might oughta comf out, simply take a 1/2" or 13mm open end and open the trans cooler line at the radiator. Turn the truck on and it'll puke juice plus make a mess if you ain't ready. Other than a drain plug on your transmission pan- that's the best way to correct your overfilled transmission.

Good luck!
 

Forum statistics

Threads
44,168
Posts
950,798
Members
36,284
Latest member
RogerioHR
Top