I have an oil leak from one of the two oil cooler pipes to the gearbox on my 1998 X308, and they do seem quite difficult to get at for repair/replacement.
I read that the oil pressure is quite low in these pipes, and that replacing them with a decent quality hydraulic flexi pipe(s) is a much easier fix than trying to negotiate original fittings. Apparently, cutting the metal pipe at each end (obviously after any damaged area) and fitting a suitably sized flexi pipe does the trick if you make sure each end is properly secure with jubilee clips or similar. Does anyone know if this is correct or had the experience, if so, what size bore of flexi pipe is required? It all seems too easy, but maybe it will work if done with care in mind?
The leak is getting quite bad, and I have a problem with the gears changing up from 3rd to 4th, I can be at 3 1/2k revs and still it won't change up, however, flicking the Sport switch on there's no problem in changing any gears? Low gearbox oil level?
As always any help or opinion is welcome

 

I can't give you any input on the flexible hose you wish to use but, I can tell you that it's most likely the collapsed engine mounts that sag the engine enough for the aluminum transmission oil cooler tube to contact the subframe. I've encountered this many times but we've always replaced the whole cooler tube. In fact, this is how I bought my 98' XJR from the previous owner. I wanted to pull the transmission to replace the rear main seal and oil galley seal above it anyways. I actually pulled the cooler tube out and had the hole soldered up and it's been fine ever since.

 

I have seen the PAS hose crimp steel section wear a hole in the gearbox cooler lines.

I have had success with cleaning the damaged section WELL, then split a piece of hose to fit around the aluminum pipe. Apply Silicone sealant and clamp the hose TIGHT. Let it dry and check for leaks.

There is not much pressure so it should hold up if it is done correctly.

bob

 

I had a cooler line leak that I repaired today on the 98 xj8 that I sold. The leak was inaccessible to use motorcarmans method. I could barely see it and was unable even to get my hand there. The leak was caused by the power steering hose near the rack rubbing against the cooler line. I could see no way of replacing the line without lifting the motor or removing the transmission.

My solution was to fit a braided line with AN fittings. I didn't want to use rubber hose because of the line going near the cats and exhaust manifold.
I used a tube cutter to cut the lines at each end and then installed the AN fittings after flaring each end. Feed the new line near original line. Started car had no leaks then fill transmission to proper level.

The first photo shows AN fitting installed on fitting going to transmission
Seconomic photo shows other end installed at radiator.
Third photo shows line installed at transmission.

 

You should offer and market a kit because I see this fault every few years.
The PAS hose flexes and chafes the aluminum gearbox cooler lines with the edge of the metal crimped fitting.

I have seen people replace all sorts of pipes/hoses because you can't really see the actual part that failed due to the location.

Good on you!!!!

bob