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Post by etypephil on May 2, 2019 14:28:57 GMT
There are two common schools of thought about this:
1) The transmission is sealed for life and the fluid does not require changing.
2) The transmission fluid has a finite life, and should be changed every 60,000 miles.
The first was confirmed to me by a chance encounter and conversation with a ZF engineer a couple of years ago, and qualified by a local transmission specialist who said that if it is working properly, it's best left alone as the fluid thickens with age / use, partly compensating for wear in the mechanism, and that changing the fluid has been known to impair operation, because the new fluid would be less viscous, and there was a risk of contamination when removing the sump, except in clinically clean conditions not usually found in workshops. However, if problems did manifest themselves, it was worth trying, as the cost is about 10% of a gearbox overhaul.
The second I can also understand, as my previous XJ transmission (never having had the fluid or filter changed as far as I know) started to misbehave, and smell of burning at around 130,000 miles. A change of fluid and sump / filter using a Bristol Transmissions kit solved the problem entirely.
More recently, there has been a spread of services such as:
offering a full transmission flush, and fluid change via the oil cooler, which does not involve removal of the sump risking contamination, has the added advantage of a 100% fluid change, which a drain and refill does not, because much fluid remains in the torque converter.
Despite what the ZF man, the transmission specialist, and Jaguar themselves have to say, the engineer in me doesn't like the idea of not renewing the fluid, ever; it seems wrong.
Does anyone have any thoughts on, or experience of the matter, particularly the idea of a non invasive flush?
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Post by The Ghost on May 2, 2019 17:56:59 GMT
Does sound good Phil but what about the filter or if you want to change the mechatronics sleeve ?
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Post by etypephil on May 2, 2019 19:50:52 GMT
Does sound good Phil but what about the filter or if you want to change the mechatronics sleeve ? Very good points; I would prefer to change the filter, and the mechatronic sleeve at the same time, taking great care not to allow any foreign matter into the box, but I far from a transmission expert, hence asking for the opinion / experience of others. My 140something000 mile box works perfectly, so I don't want to risk damaging it either by failing to maintain it, or carrying out spurious and harmful maintenance. |
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Post by BigE on May 3, 2019 10:53:25 GMT
If you do an oil change yourself Phil, can you do a write up like you did with your super-charger one? As I've had more gearboxes then you have had jags  the oil is still new in my box (relatively speaking). I saw an American chap posted on the XKEC Facebook group a few days ago, he had a XK8 which had just ticked over 400,000 miles, in that time he has had 9 replacement gearboxes! I've been saying for years the ZF 6hp26 yearbox is made from chocolate and under specified for higher power cars. Nothing but trouble in both the BMW I had and Jaguar. I suspect the Mercedes 6 Speed from the XKR is much better. |
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Post by etypephil on May 3, 2019 12:12:14 GMT
If you do an oil change yourself Phil, can you do a write up like you did with your super-charger one? As I've had more gearboxes then you have had jags the oil is still new in my box (relatively speaking). I saw an American chap posted on the XKEC Facebook group a few days ago, he had a XK8 which had just ticked over 400,000 miles, in that time he has had 9 replacement gearboxes! I've been saying for years the ZF 6hp26 yearbox is made from chocolate and under specified for higher power cars. Nothing but trouble in both the BMW I had and Jaguar. I suspect the Mercedes 6 Speed from the XKR is much better. Will do Ed. Part of my plan is to discipline myself to take photos for the forum of anything I do Jaguarwise as I believe that many owners are fearful of doing even minor repairs because the trade makes such a song and dance of their difficulty, usually for no good reason. Some things are time consuming, but it’s only nuts, bolts, clips and circuits, just like any other marque. What you say about gearboxes is interesting; I thought that the Mercedes units fitted to some earlier Jags were their Achilles heel, and the ZF ones much better. You have much more X100 experience than I, so am happy to be corrected. |
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Post by BigE on May 3, 2019 13:45:17 GMT
I was lead to beleive the Mercedes 720 600, 6 speed on the XKR was a peach. I know first hand the ZF boxes are rubbish.
Speaking of gearboxes, it occurred to me yesterday with the increase of electric cars, gearbox manufacturers are going to slide to brankrupsy if they don't diversity.
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Post by BigE on May 4, 2019 7:21:18 GMT
I've just been reading about automatic gearboxes, it seems the ZF 8HP is very good and well respected as a class leader - nothing about durability though.
The general consensus is that the 1960-1970's 3 speed automatic gearboxes by GM (Hydromatic) and the other one I can't remember are still excellent, slow, yes. Durable, bullet proof and can be fixed by any mechanic at any local petrol (aka gas) station.
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Post by etypephil on May 4, 2019 8:01:49 GMT
I think that we have our wires crossed a bit; the ZF6hp is a tough as old boots
6 speed gearbox as fitted to Jaguars from X350 onwards, and many other cars, superseded by the 8hp 8 speed; another excellent piece.
Your XK8 surely has the earlier 5 speed box, which was marginal at best for the power of many of the cars to which it was fitted.
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Post by BigE on May 4, 2019 8:25:04 GMT
Sorry, previously I meant the 5HP not 6HP.
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the oil is still new in my box (relatively speaking).