Auto gearbox fluid life / temperature

[poprivet]

Us XJS owners are in the fortunate position of having automatic gearboxes where we can change the oil and filter easily and cheaply, compared with later Jaguar models. I expect that the majority of us tend to ignore preventative maintenence though, only reacting when a problem happens.

I've been looking into the recommended frequency of fluid change and realised that degredation is more based on temperature rather then mileage. A car that does many motorway miles has a much easier time then one used in town and 'spirited' weekend A road use

An article I found interesting is this:

http://www.digi-panel.com/trannyoil.htm

I doubt if any of us know what temperatures the fluid in the sump or torque converter run at, but for sure it makes sense to me to do a fluid and filter change every few years. As you will know, you can never drain all the fluid out, so regular changes are the way to go. The article was written for 4x4 vehicles which have a very hard working box, but the principles are the same.

Ask yourself when was yours done last? Maybe a little project for the near future.

[Tintin]

Couldn't agree more. You only have to compare the cost of a new gearbox with the cost of a fluid change - why take the risk? Not so sure about the "easily" bit thought - my 1996 gearbox sump has no drain plug - you might be forgiven for thinking that Jaguar want to dissuade you from doing it so they can sell you a new box every 15 - 20 years!

Robbie

[ptjs1]

Pop,

Good prompt! I think I'll do my fluid and filter next month

Robbie,

It may be that someone has fitted a non-original gearbox as the standard ZF4HP24 box as originally fitted to to your car does have a sump plug.

Paul

[Tintin]

The W/S manual certainly shows a plug and tells you what to do with it (!) - but it just isn't there, and I'm sure it is the original box. Anyway, I'm thinking of having the pan drilled and a tapped insert fitted when I next drain the fluid. The manual shows the plug position at rear centre.

The other benefit of a fluid change is likely to be an improved gearshift - my Volvo T6 shift was much improved after a fluid change at 100,000 miles - although in that case it was possible to power flush the entire contents in one go.

Robbie.

[ptjs1]

Robbie,

that is strange, isn't it. As you say, the sump plug is located towards the rear on the base of the sump. It's an Allen-headed plug. Perhaps the sump has been changed at some time.

I guess it's not too bad as you need to remove the sump to change the filter so, by carefully disconnecting the dipstick tube, you'll be able to extract a significant part of the fluid prior to sump removal anyway.

Your point about the Volvo flush approach is interesting. I had read about this some years ago. It apparently involved the filling of the box with new fluid, disconnecting one of the transmission cooler pipes, running the engine and box to pump about 3 pints out of the cooler pipe, reconnecting the pipe. topping up the box, disconnecting the pipe, running the engine etc. With a few cycles, they then managed to renew much more of the fluid, particularly that which would otherwise have sat in the torque converter. I wonder if any of the Jaguar specialists use this approach?

Paul

[Tintin]

Hi Paul

Your summary of the principles of the Volvo change are correct and it wasn't a difficult job to do; as with most things access was the trickiest part of the job. In essence the idea is that the fresh fluid used in replenishment chases the old fluid out when the pump runs. By using a clear plastic drain tube connected to the cooler feed you can see the change in colour when the old black fluid gives way to the fresh red stuff.

If any member has experience of this method in Jaguar boxes I also would be very interested to hear about it.

For anyone who wants to know more about it the detail of the Volvo method is at http://www.volvoxc.com/forums/showthrea ... ssion-Post

Robbie

[Jagracer47]

Old thread, but I took the box out and emptied the torque converter, put a few litres back of new Dexron 3, and put it back together and refilled it, job done, you only do it once.