Thread: ZF4 Transmission cooler thoughts..

Originally Posted by Slunnie

If it has push on and a hose clamp fittings then its not up to the job, if it has multibarb pirtek fittings or high pressure fittings then it will probably be ok.

I've spent a lot of time and money working this out, not to mention a lot of ATF on the road, on workshop floors workshops, on tow trucks and on my back window..

Towing, the additional cooler is the best thing you can do for it. I run mine behind the grill and in front of everything else. As soon as I got the the cooler type under control the transmission has been 100% reliable, best mod for the gearbox. My probs came from more power torque from the engine and mud in the ATF cooler in the original location.

I will take your advice on the fittings, its the hose clamp push on type. No problem I can take it back anyway too many second thoughts. I'll dig around and see if i can find a p38 one or somthing similar.
I've got a big tow tommorow so I fitted a scoop under the front to push more air into the cooler and rad.
Not in a rush though so I'll just take it easy, carting blueys so a bit of weight not as much as a car though...
Cheers Jim

Originally Posted by Pedro_The_Swift

Ok,, One of those I counted is the standard auto cooler,,,

the second is the biggest PWR they make, up the front just behind the grill,,

I have since put a thermostat in line between the standard cooler and the second one,,
untill the auto fluid reaches 80,, it runs as designed by LR,,
when the standard LR auto fluid reaches 80 the thermo opens and the second cooler comes into play,,

You used a Derale thermostat for memory didnt U Pedro???

I can vouch for the P38 cooler in series with the standard intank item. I did that a while ago and it works a treat, even with 'spirited' driving, deserts/sand and big motor... I have a 4HP24 with the biggest TC which helps. The 4HP22 with medium TC ran a bit warmer (more slip) but it still held it.
With additional coolers there are a couple of things (apart from heat transfer). 1. Restriction, and 2. Strength. The factory one is designed for both. It's also the reason I won't fit an aftermarket radiator with unknown coolers in the tanks as they are often restrictive and designed for lesser requirements. The 4HP likes a lot of flow through the circuit (hence the bigger lines). I would not downsize to 3/8" and equally I would generally not run a 3/4" core. Use a 1-1/2" core stacked-plate or stay with factory items...
Quick check... blow hard through the cooler you want to use. If you can't exhale pretty much as fast and easily as without it being there then avoid it... any significant backpressure means restriction when pumping oil at good rates.
I like the idea of the thermostat and may do that myself one day. Open road cold day the trans runs a bit cooler than it should. 90deg is fairly optimal. 10 deg either side of that is a great zone to be in.

Originally Posted by LRJim

I will take your advice on the fittings, its the hose clamp push on type. No problem I can take it back anyway too many second thoughts. I'll dig around and see if i can find a p38 one or somthing similar.
I've got a big tow tommorow so I fitted a scoop under the front to push more air into the cooler and rad.
Not in a rush though so I'll just take it easy, carting blueys so a bit of weight not as much as a car though...
Cheers Jim

Jim, if it helps, this is the unit that I use. $ but it works and is reliable.

Aux Transmission Oil Cooler | MODIFICATION | Davis Performance

Originally Posted by Slunnie

Jim, if it helps, this is the unit that I use. $ but it works and is reliable.

Aux Transmission Oil Cooler | MODIFICATION | Davis Performance

🤤🤤 Its almost as much as I paid for the whole car 🤣🤣 I guess it would be money well spent though
Thanks for the link, Cheers

One rrc with 3.5 supercharged motor i run 2 of these coolers - temp gauge shows needed it when towing over ranges.
On the other 3.5 rrc that run off road with disco auto i run one of the DC coolers in series with the disco hedgehog cooler. Again temp gauge showed that when doing steep off road on hot days needed extra cooling. We flog these trucks so well tested.

Originally Posted by LRJim

🤤🤤 Its almost as much as I paid for the whole car 🤣🤣 I guess it would be money well spent though
Thanks for the link, Cheers

https://www.ebay.com.au/itm/DERALE-2...vKyJ:rk:4:pf:0

Slightly off topic, but what brand filters are we all using when servicing out 4Hp's???

I see Ryco do one, as does Transgold.

Any other options or suggestions?