Transmission Cooling

[Rebel]

Is anyone using an external transmission cooler instead of the engine radiator?
Do they work well
Do they connect to the original cooling pipes, or do they connect to the gearbox
Will a fleabay purchase be ok or does it need to be a specific one
What size would I need

TIA

[mopar_mark]

I have used a individual radiator set up for gearbox cooling for the last 15-20 years.

Mine have all been plumbed directly to the gearbox & completely independent of the engine cooling system.

I primarily use separate set up as it helps dissipate heat, which is the downfall of auto trans.Especially when using the likes of a Trans Brake.

Generally the bigger the better, you can also purchase coolers with there own fan, or use an air cooled version. Dependant on room, a popular choice is in front/behind the radiator.

[Rebel]

Thanks Mark,
Is it possible to overcool the trans, if the cooler is too big?
My application is for a 383 and 727, neither are modified in any way

[Blue]

Yes you can overcool the trans. like the engine it is best for long life if its running around 180 degrees, having the cooler as part of the engine radiator warms the trans up quicker and helps to regulate the temp. Unless you have good reason to do so, the standard style set up works perfectly well. You can plumb a small auxiliary cooler into the circuit if you are towing. Race set ups are totally different, there is a lot of heat build up in the trans that needs to be got rid of.

[Pete]

I would always take note of what Blue says, as he has had lots of experience on 727's / 904's.

My only observations on this is as follows:

I always liked the idea of a separate Trans oil cooler in the unlikely event that the Radiator gets damaged so there will ne no ingress of water into the Transmission. I accept that this is a bit tenuous, but if you have upgraded the standard radiator, there is a chance that it won't have a trans cooler built into it anyway.

I can remember that Guy Papworth installed a huge separate oil cooler and big lines on his Barracuda.
He then suffered with very high transmission oil temperature.
He knew this because he had a gauge fitted for every purpose known to man - including a "Gauge-ometer" !!!

It turned out that the rate of flow through the cooler was so great that it did not have time to impart the heat from the oil so that the cooler could not dissipate the excessive heat.

I think the fix was to install restrictors to slow down the speed of oil circulation.

On a standard car it is probably easier just to leave it alone if it is functioning.

[Rebel]

Thanks guys, all valuable info. While I will be using it for some track time, it’s in no way going to be enough to warrant upgrading to an external cooler by the sounds of it. As I’m upgrading and replacing some things as they wear out, I was wondering if it was an idea to add a cooler or not. The new rad does have a built in cooler so I’ll leave it as is. It’s also highly unlikely I’ll be towing anything with the charger anymore

Thanks for all the advice