Thread: auto tranny help

Apparently the fluid travels in the reverse direction through the cooler during lockup. Maybe pressures increase due to this

it's not on the return to the sump. its on the outlet to the sump. the 150psi is at 2000rpm. if however like many of us that tow caravans we use the engine braking system to slow down on steep descents therefore the pressure will exceed the 150psi margin. As said earlier there is only one line the gearbox oil comes from the box into the cooler and back to the gearbox. does not go through the radiator like the later disco 1's do.

I don't think you will be ale to convince me otherwise. since i just installed a pressure guage and took my disco for a 30k drive. pressures ranged from min at idle of just under 100psi to 210psi at 3500rpm. and since when going down hill i reach 4000rpm using my gears i don't think i will even attempt your solution. however i will be going for a pwr oil cooler but one with screw thread connections not push on. but thanks for your input.

the pressures i mentioned were at the return to the transmission. so yes the return does operate at those pressures.

Originally Posted by bealzabab

the pressures i mentioned were at the return to the transmission. so yes the return does operate at those pressures.

The maximum potential pressure is.about 400psi.

However pressure is only the function of restriction to flow, so long as you don't have blocked lines, kinked lines or fouling of the valves and galleries in the cooler circuit you won't see those kinds of pressures.


I know what I would be specifying as the minimu pressure rating for the lines and cooler tho.

I spent the $$ and got the proper pressure guage that has the guage sitting ontop of the lines. all you do is take either inlet pipe or outlet pipe off the oil cooler (it doesn't matter which as the oil cooler is just a straight through pipe) and connect one end of the guage to the pipe and the other end to the oil cooler. and it then tests the pressure. i have put it on oth inlet and return pipes with the same result. so the results i have got back from the pressure test is +-5psi as that is the tolerance on the pressure guage.

I will say this one more time and see if you can understand. the transmission does not go through the radiator. it goes direct from the transmission to the cooler and back to the transmission. i don't know how many ways i can say that so you might be able to understand. it was only after the upgrade in 94 that the transmission went through the radiator.
transmission to cooler.
cooler to transmission.
NO RADIATOR INTERACTION.

this is what you said that prompted the response.
"As your radiator coolant is down usually well below 180F when travelling above 80KPH, the transmission cooler in the radiator should keep the transmission well within operating range. The standard additional external cooler should keep it even cooler. So if your car is operating at normal water temps and the transmission warning light never comes on, it is unlikely that you need any additional cooling for the transmission."

if that is not saying the transmission goes through the radiator then what is it saying.
and without changing the entire setup, new radiator, new pipes ect at a cost of about $2000.00 i can not get the transmission to go through the radiator.