Thread: 4HP22e cooler line pressure?

Originally Posted by Tins

X2. The QR connector was my first experience of this, after he who shall not be named did my trans in the first place. I managed to reconnect it, but it blew again some time later. Then it blew the hose off the pipe. I don't think they like being disturbed much.

Yep, the crimp fitting has a reputation of letting go, as well as the quick connect on the OE hoses.

Touch wood... I did have to remove to trans cooler last year due to it having a hair line crack, I did read about the quick release fittings and made sure they were clean before, during and after, no leaks but still keep an eye on them. If I had plenty of time and $$$ I would get some new steel lines made up (at a previous work place they had all the gear so it would have been easy) currently I'm just getting all the bits together so that once the trans is back and feeling better I can then fit everything and get the disco ba K on the road, trying to go through and cover everything but not spending a fortune on it at the same time...

Cheers

Redd

Originally Posted by Reddirt204

no leaks but still keep an eye on them.

No need for that. If they let go you'll know....

Originally Posted by Tins

No need for that. If they let go you'll know....

Yeah the trick is pulling over in time before the gearbox eats it's self. It was fairly convenient of mine to blow off in the workshop instead of down the road.

Originally Posted by admiralranga

Yeah the trick is pulling over in time before the gearbox eats it's self. It was fairly convenient of mine to blow off in the workshop instead of down the road.

Indeed

I am replacing my factory trans cooler with an aftermarket one and have already purchased the required hose and pipe fittings from a well known hydraulic parts supplier. My preliminary reading when planning for this mod suggested that although AT unit pressures in the ZF4HP22 run as high as 150psi the cooler lines DO NOT run at as high a pressure EXCEPT when the Torque Convertor goes into “lockup” at which time the line pressures will RISE up to 60 > 70psi. From memory this info came from a Jaguar Workshop Manual. I will endeavour to find the reference but in any case my cooler mods will be able handle pressures in excess of the AT unit pressures.

Originally Posted by onebob

I am replacing my factory trans cooler with an aftermarket one and have already purchased the required hose and pipe fittings from a well known hydraulic parts supplier. My preliminary reading when planning for this mod suggested that although AT unit pressures in the ZF4HP22 run as high as 150psi the cooler lines DO NOT run at as high a pressure EXCEPT when the Torque Convertor goes into “lockup” at which time the line pressures will RISE up to 60 > 70psi. From memory this info came from a Jaguar Workshop Manual. I will endeavour to find the reference but in any case my cooler mods will be able handle pressures in excess of the AT unit pressures.

That was my findings as well re line pressure during lockup.

TBH, if you take a look at the cooler itself, there is no way it could handle more than 30 psi sustained IMO.

I've got 2 systems here mended with high pressure chemical resistant hose (boomspray) with hose clamps.

And I'm probably running higher pressure on mine than anyone on here ATM.... Cos I can....

Cheers
James