transmission/oil cooler lines

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.

Ryanbrown36

Junior Member
Joined
Nov 17, 2024
Posts
17
Reaction score
15
Location
Ontario, Canada
First Name
Ryan
Truck Year
1981
Truck Model
c1500
Engine Size
350
Hey guys, Im finishing up a Oldsmobile 5.7 diesel to Sbc swap and noticed my transmission cooler has 4 ports. I'm hoping to start it up this week in hopes of getting it on the road for a bit before winter and want to know what I should do with it. I'm not very knowledgeable about this stuff and learning as I go here so might be a dumb question. I'm just trying to get it started as soon as possible and don't want to spend money in the wrong places. from what I've read I can buy a new trans cooler with two ports, run a oil cooler or was hoping I could maybe plug those two holes. thanks in advance
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,444
Reaction score
8,676
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Is this a factory cooler? Possibly a water to oil heat exchanger? If so you'll want to run heater hoses through 2 ports transmission lines through the other 2. I personally would use a radiator with the built in transmission cooler and if I was going to run an external cooler I'd run transmission pressure line to external cooler,external cooler to radiator cooler,back to transmission. That way the radiator regulates transmission oil temperature so the ATF is not too cold
 
Last edited:

Ryanbrown36

Junior Member
Joined
Nov 17, 2024
Posts
17
Reaction score
15
Location
Ontario, Canada
First Name
Ryan
Truck Year
1981
Truck Model
c1500
Engine Size
350
Oscar this a factory cooler? Possibly a water to oil heat exchanger? Of so you'll want to run heater hoses through 2 ports transmission lines through the other 2. I personally would use a radiator with the built in transmission cooler and if I was going to run an external cooler I'd run transmission pressure line to external cooler,external cooler to radiator cooler,back to transmission. That way the radiator regulates transmission oil temperature so the ATF is not too cold
I am not sure if it is a factory cooler but if I had to guess I would say yes, I believe the two extra ports used to run to an oil cooler at the oil filter. I would prefer to not have to buy a new radiator if possible. My heater core lines currently run through the rad if that helps and all ports on the trans cooler fit a 3/8 hose.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,444
Reaction score
8,676
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I am not sure if it is a factory cooler but if I had to guess I would say yes, I believe the two extra ports used to run to an oil cooler at the oil filter. I would prefer to not have to buy a new radiator if possible. My heater core lines currently run through the rad if that helps and all ports on the trans cooler fit a 3/8 hose.
If you have a radiator with 2 ports for transmission cooler,just run lines from the transmissiin to the radiator an forget about.
 

Ryanbrown36

Junior Member
Joined
Nov 17, 2024
Posts
17
Reaction score
15
Location
Ontario, Canada
First Name
Ryan
Truck Year
1981
Truck Model
c1500
Engine Size
350
If you have a radiator with 2 ports for transmission cooler,just run lines from the transmissiin to the radiator a forget about.
I would but my radiator doesn’t have any ports for the transmission cooler
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,444
Reaction score
8,676
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Pics. Hard to tell what you have with out pics.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
What year is your truck? I don’t recall any heat exchanger on my 81 GMC, but it’s been 30 years since I swapped in the 455. I have slept a lot since then.

I’d suggest using a radiator with a trans cooler built into it, or using a stand alone cooler.

Either way, don’t scrap the factory olds engine frame mounts. There are people who will buy them.
 

Ryanbrown36

Junior Member
Joined
Nov 17, 2024
Posts
17
Reaction score
15
Location
Ontario, Canada
First Name
Ryan
Truck Year
1981
Truck Model
c1500
Engine Size
350
What year is your truck? I don’t recall any heat exchanger on my 81 GMC, but it’s been 30 years since I swapped in the 455. I have slept a lot since then.

I’d suggest using a radiator with a trans cooler built into it, or using a stand alone cooler.

Either way, don’t scrap the factory olds engine frame mounts. There are people who will buy them.
The truck is a 81, I think I forgot to mention that it has a stand alone cooler (that has 4 ports). Yes I did end up keeping the mounts as someone offered me $100 for them, is that a alright price for them?
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
I’m not sure what a fair price is, never had a pair to sell. Since im an Olds guy occasionally people ask if I know or have frame mounts for sale. The only pair I have are on my truck.

I can’t think of any reason to keep the existing cooler. Either use a radiator or a stand alone cooler. Least amount of questions going that route.
 

Forum statistics

Threads
44,156
Posts
950,539
Members
36,268
Latest member
JUKA
Top