Ten years old and under 60K miles decided it was time to finally try a transmission flush. Note there were no known issues but for peace of mind and considering I track the car almost exclusively now, I figured this would be just another part of the new maintainance routine.

At first I was going to buy 20 litres of LifeGuard6 fluid for just over $400 and have a friend borrow for a small fee a flushing machin but decided to ask the nearest main dealer if they offered the service and if they used Jaguar fluid. The advisor confirmed they offered the service, of course used Jaguar fluid and charged less than $300. Well that seemed to be a no-brainer! So I booked the appointment and had them do it.

All seemed well at first until I found a large pool of red fluid under the car the following morning. I promptly re-visited the service department and was told the sleeve was leaking, of course. I questioned the advisor about the color of the fluid as I was under the impression Jaguar/ZF fluid was a light golden color. He looked puzzled and said that Jaguar fluid has always been red and no other color.

For less than $100 for a new ZF pan and sleeve overnighted from FCP, I had them perform the labor for $400 (their rate is nearly $200 per hour) and spoke with the technician about the fluid color. He informed me they haven't used Jaguar fluid in over 10 years and they believed the whole idea of proprietary fluid to be a joke. He said they use BG transmission fluid that meets the specification for ZF/Jaguar and have never had a problem.

My impression so far after over 300 miles is I can tell no diference. Still salty about the advisor’s lie though.

 

Interesting indeed Jeremy. Long ago I was definitely in the camp of only using OEM liquid gold and that's what I've used on my last (actually only) two drain and fills.
Certainly there's been the warranty rationale for keeping with Lifeguard and then we've heard from Techs on this forum that the TCM software is tuned specifically for the fluid specs.

Subsequent findings have shown Mercon SP to have the exact same properties as Lifeguard. I've also read Pentosin (sp) meets the spec. Then lastly, there are guys on the X350 forum who've used Mercon and never had an issue either. Any debates on the topic can be found in BMW, Audi, Hyundai forums as well.

But you also take your car out on the track and still see no difference. While I'm not familiar with BG, you are so we can add that to the list.

If and when the time comes for another drain and fill, I'll be doing a full flush instead and with Mercon SP.

 

I think the use of manufacturer fluids is more about variable control than anything else. Unless specific data is cited to justify the use of a fluid, any major brand fluid that meets the specification should be sufficient for the application.

BG dealer products have been around for sometime and provide an automatic extended warranty for the parts they are used in. So now I have $2k warranty coverage for the transmission. Some years ago I had a differential self destruct on a truck that was 1k miles passed warranty and BG covered the entire cost even though it was a defect and had nothing to do with the fluid.

https://www.bgprod.com/catalog/trans...synthetic-atf/

 

UPDATE: Its been 2 yrs since I did this repair and flush. Had the car up changing oil and brakes 2 weeks ago. Absolutely zero leaks or problems w/trans lines and trans function.

 

Interesting. I used Jaguar liquid gold and a lot of it. Meeting specifications most important.

 

I met specs with Motorcraft fluid, 9+ quarts of it. I can't see how it is stated 'six quarts' though, unless my torque converter was totally empty. I can't see that happening though.

 

ZF Lifeguard 6 transmission fluid ZFS-S671 090 255 is the same as Shell M-1375.4.

I used Amsoil ATL 100% synthetic fluid and the shifts are silky smooth but this is comparing 13 year old fluid to new transmission fluid. I have used the same fluid in a BMW 335i M sport (with a tuned) and that car had over 250,000km before I sold it. I changed the fluid on the BMW at 60,000km and haven't changed the fluid since then. The BMW still running strong as it was sold to someone local and they drive it harder than I ever did.

 

Dummy question: with our transmissions, is there a difference between a "change" and a "flush?" My dealer is willing to do a "change" (though they don't always do it) but they do not recommend a "flush". (Don't know why)
Over the past year or so I've noticed that the car fights me a little on downshifts, especially above 50 mph. They are definitely no longer "silky smooth."

 

A flush is when a technician hooks up a machine to force fluids throughout all the passages at a lowish pressure. I'd say DON'T DO THAT!!! It can loosen stuff up that you don't WANT loosened up. Course, there are Reverse Flushes that are more prone to dislodging gunk, and regular flushes that go the 'normal' direction, which are a bit safer to do.
A CHANGE is Remove the Pan and replace it, fill the trans with fluid. GTG.

 

I used 13 litres. After draining and replacing the pan/filter I cycled many litres through the in/out cooling lines until the fluid was clean. 13 liters of Jaguar ATF at $60CDN/litre. My 2014XKR only had about 13K miles on it. I noticed no difference in performance; however, I have peace of mind. Our transmission fluid is not synthetic, it is mineral oil based and degrades over time.

 

Agreed a standard flush done by most shops is not a good idea. However ZF Master Centres do have a slow flush procedure approved by ZF

There is no real pressure involved, it's primary focus is giving you 98% new fluid as empty's the TC. There are (IIRC) only 2 x ZF master centres in the whole of the UK, one in Kent and the other in Glasgow.(Scotland). I went for Scotland as it's a nicer drive

https://www.mackie-transmission.com/

Cost is £440 less the UK forum discount of 10% and they actually slow flush it through with LG6. I had my tranny flush booked 3 x last year but the pandemic killed those as couldn't find hotels that were open...and didn't fancy sleeping in the car!

Booked in again fr 29th July this year when I hope I'll actually get it done

My car's on 58k miles currently.

 

The main dealer doesn’t flush, they do a fluid exchange with a machine which slowly pushes new fluid through the cooler lines, forcing the old fluid out while the car is in gear. This provide a safe and complete replacement of all fluid. They’ve been doing this for 20 years without issue.

I reckon there’s some misuse of terms and techniques with regards to flush, change, drain, exchange, fill, etc.

 

I bought my '07 XK at 113K miles. Soon after, I worked out that the transmission had been living in the "fluid lasts a lifetime" zone. It was feeling sluggish, sticky and just not happy and was getting worse. I bought 9 litres of the expensive Lifeguard fluid and a new pan and set about doing it myself. I found a post on the forum here that described a method of using the transmission coolant ports to run the new fluid through the system using the systems own pump. I built the setup to do that, only to find that it was near impossible to attach the tubing to the coolant ports due to lack of space. I went back to the research and found out about the Mercon SP, sourced 13 litres of it locally and used the method of using it all up in a fill, run, drain and refill until it was just about clean looking. The Mercon cost a LOT less and is red. The oil that came out was filthy and showed the tranny definitely had had a hard life.
The end result was a way better, but not silky smooth operation in the low gears. No leaks and peace of mind for the time being. 7K miles later it's still running well.
If you have the ability to safely lift the whole car at least one foot or more, you can do it for around $250-$300 including the pan. I kept the Lifeguard oil with the view that it could be used if I have to have the transmission replaced in the future.

 

It all comes down to semantics, in my view they are all the same, if you change out some fluid it is still change, or exchange, or whatever.

With ZF transmissions though there is a ton of fluid in the torque converter and most DIY fluid change/drain/exchange/flush/fill ends up being partial. To do a COMPLETE change/drain/exchange/flush/fill it has to be as you mentioned, a Tranny Dialysis machine . Or, as others have done, change/drain/exchange/flush/fill several times to try and accomplish the same end result.

Draining the Torque Converter – CarTechBooks

last paragraph from the car tech page linked above:

" if you still want to get that old fluid out of the torque converter and can’t access cooler lines, there are two alternatives. First, you could just change the fluid a couple of more times. Sure, that’s messy. But, if you’ve got a reusable sump gasket, it won’t cost more than the price of the extra transmission fluid. You won’t be able to get all of the old fluid out, but you’ll be able to come pretty close. Second, after changing the fluid, you could use a hand pump to suction out fluid from time to time, replacing as much as you remove. That saves you the trouble of dropping the pan and, eventually, you end up with the same result."