Gearbox flush

[cornershop]

Hello

Has anyone undertaken a flush of their ZF 6HP26 gearbox? Any issues to report?

Wondering if a drain, flush and re-fill is always recommended over a drain and refill ?

http://www.gearbox-flushing.co.uk/servi ... flush.html

Thanks

[J44EAG]

I am personally a great advocate for flushing. A similar process is available for engine decontamination from EDT and is right on the top of my list of very useful after-market processes.

Gearbox flushing has been around for many years but operators of the process are few and far between. I`m glad to see your post on the subject and I have bookmarked your link for future reference. Normal gearbox oil and filter changes figure on Jaguar V8 service schedules at each and every 60k mile service interval. Whether they get done by owners is another matter. The going rate for a standard X350/XK/XF gearbox oil and sump/filter change is around £350 and worth every penny as preventative maintenance. When buying one of these cars, it is important to look out for the relevant paperwork to substantiate the work. Cars without that documentation are worth less than a car that has the proof. Worn out oil eventually wrecks gearboxes. Note that at one time, Jaguar and ZF refused to acknowledge that gearbox oil needed regular changing. Only when many owners suffered major transmission failures at relatively low mileages did the attitude change. "Filled for life"! What a totally misleading joke that was!!

So what you have turned up is a company offering full flush facilities. This is good news indeed. The price quoted in your link is probably just for the flushing process. I suspect that replacement oil and a new sump/filter will incur additional costs.

The flushing process goes beyond recommended Jaguar service schedules and you are likely to find a dank response from many Jaguar appointed Main Agents. I would expect most to tell you a flush is un-necessary. As they wouldn`t be making any money themselves through endorsing the process, a negative response is likely to prevail. What you do as an owner is up to you but I would suggest that any enhanced maintenance can only be for the good. Flushing removes the crud that a simple oil and sump/filter change cannot and does not achieve. The choice to be made is "Do you want to run your car with crud in your gearbox"? If you don`t, then flushing makes eminently good sense. In my opinion, go for it. I`ll certainly be looking at having the process run on my XJR when it hits the 100k mile mark.

Thanks for posting the link.

Mike K

[cornershop]

No probs Mike

I believe it’s a while you wait service, and something I will consider in the next few months.

I’ll post up findings, I’ve emailed my local specialist for more details.

[J44EAG]

This is of interest to me as I live in the South East and their operations bases are quite close to me.

The only other local full flush machine I`ve come across near to me is at the 4x4 Land Rover independent garage at Swanley in Kent.

Thanks for the heads up on this.

Mike

[cornershop]

So i received a quote, not cheap (all +vat) but something i’m still planning on undertaking:

[cornershop]

I eventually had this done earlier this week at Autotech Independent BMW specialist in Langley near Slough.

It cost £630, which included 12 litres of ZF Lifeguard 6 fluid, genuine ZF pan/fiter, bolts and 3 hours of labour. They use a machine to flush the old fluid and fill until they see clear/new fluid. Remember a drain and refill only replaces 7 litres of fluid and doesn't touch the fluid in the torque converter.

Downshifts are much smoother now when approaching roundabouts, junctions etc. It does also appear to be accelerating quicker too; regardless, upshifts are now imperceptible.

Not cheap, but potentially could be done cheaper as Autotech allow you to supply your own parts. There is an equivalent fluid sold by Smith and Allan which one advocate believes is the same fluid supplied to ZF by Shell. A Febi-Bilstein alternative is also available - both of which would knock150-200 of the final bill.

[J44EAG]

An excellent appraisal on the benefits of true preventative maintenance.

Yes, it was pricey but you get what you pay for. If this type of maintenance gets ignored, you can expect eventual repairs which will cost vastly more. With a re-con gearbox costing something like £3k, the flushing maintenance certainly makes sound economic sense.

Thanks for posting the results of the experience.

Mike

[trampintransit]

Given that the full flush and new sump and all looks like over 500quid, I'll not be doing that to my one grand, 100k car..but I guess it's probably worth changing the fluid ... or at least what of it I can get out...which begs the question, can the bulk of the fluid be sucked out via the filler hole with a sucky pump thing .or is there too much gubbins in the way?

[trampintransit]

Check what the manual has to say about refitting the gearbox filler plug...

"Using the special tool and a torque wrench, tighten the transmission fluid filler plug.
• Tighten the transmission fluid filler plug to the torque given by the calculation.

• To make sure the transmission filler plug is torqued to the correct specification. Using the special tool and a torque wrench the following calculation steps must be followed. Step 1. Multiply 35 Nm by the effective length of the torque wrench (1). Step 2. Add the effective length of the special tool (2) to the effective length of the torque wrench (1). Step 3. Divide the total of step 1 by the total of step 2. Step 4. Set the torque wrench to the figure arrived at in step 3.
• Tighten the transmission fluid filler plug to the torque given by the calculation.


IT'S A PLUG?!?!?!?

[Popsjag]

The gearbox filler plug is on the rh side of the gearbox casing - needs an allen key, but space is very tight - don't even think of removing this without the engine running or you will be covered in transmission fluid!

The drain plug is on the bottom of the gearbox sump - which is also the filter (all one part). Don't even attempt to mess with the transmission unless you know what you are doing!

I certainly wouldn't want to suck out the old fluid through the filler (good luck even trying that!) and put new fluid in - using the old filter/sump!!

[trampintransit]

I was asking about the old fluid removal via the filler because someone somewhere told me ( on FB page I think ) there there was no drain plug. Now that it's clear that there is, and if I'm interpretingthe workshop manual correctly, then replacing the ( bulk of ) the trans oil is no different from any other automatic. Drain, replace a,d check levels with engine running after cycling through the gears usingthe filler rather than a dipstick to check levels. The only difference being that the level is checked at a specific fluid temperature? What am I missing?

[BrianG]

I was asking about the old fluid removal via the filler because someone somewhere told me ( on FB page I think ) there there was no drain plug.

Just for info it's the differential housing that has no drain plug (apart from some early X350s, apparently). The only way to change the diff oil is to suck it out through the level plug hole. Another job well worth doing after you've done the gearbox!

[trampintransit]

The gearbox filler plug is on the rh side of the gearbox casing - needs an allen key, but space is very tight - don't even think of removing this without the engine running or you will be covered in transmission fluid!

The drain plug is on the bottom of the gearbox sump - which is also the filter (all one part). Don't even attempt to mess with the transmission unless you know what you are doing!

I certainly wouldn't want to suck out the old fluid through the filler (good luck even trying that!) and put new fluid in - using the old filter/sump!!

WITHOUT the engine running ? The manual makes no mention of that? ( page 2986 )

[Popsjag]

If you remove the gearbox filler plug (and you haven't drained the oil, by removing the gearbox sump plug), you will get covered in oil because the oil level is above the level of the filler plug WHEN THE ENGINE IS NOT RUNNING!

If the engine is running, the oil level should be at the bottom of the filler plug orifice - but if you turn the engine OFF whilst the filler plug is removed, all the oil that was spinning through the torque converter gets dropped back into the sump (raising the oil level) - therefore it will come straight out of the filler plug orifice!!

Obviously, if you have drained the oil out of the gearbox you would not be stupid enough to start the engine again (would you?) until you've replaced the sump/filter and filled the gearbox up until the fresh oil starts coming back out of the filler orifice - and then the correct procedures are followed to ensure the gearbox is filled with the correct amount of oil.

I would not recommend anyone to replace the gearbox oil and sump/filter unless they knew 100% they could do it right.

[J44EAG]

Agreed fully.

Often the sump screws are eroded and that in itself can take a couple of hours to sort out. Then there is the connector sleeve to change. They can be quite a fiddle. Ideally, a four post ramp allows full and free access. The ramp should have a hydraulic jack fitted to enable the back wheels to be raised from the floor when cycling the new ZF Lifeguard (and nothing else) around the gearbox. Oil temperature is critical to ensure the gearbox is filled to the right level. Once all that has been done, a gearbox ecu re-flash to coax the gearbox into the correct operating parameters is usually recommended. These gearboxes are sophisticated pieces of precision engineering and are a million miles away in design from gearboxes of yesteryear. As such, in my opinion, they are best serviced and maintained by competent individuals from within the trade with the appropriate training and competency levels.

I prefer to put any gearbox service trade out to my local independent garage operator. For around £350, he does the job for me professionally and takes full responsibility for satisfactory final operation. His time served expert knowledge is worth every penny of his labour fees and I end up with a proper receipt detailing the work done to join other invoices on my car file. If and when I come to sell my car, I can refer to the file and demonstrate the car has been maintained to the highest standard. That is far more convincing that just invoices for materials alone.

It isn`t a bad idea to realize these cars were never designed to be maintained by even the most enthusiastic amateur Jaguar mechanic. The gearbox is probably the most complex item in the car and replacement/reconditioning work would cost a minimum of around £3k if something went pear shaped. In my opinion, ZF gearbox work should be left to the professionals unless you have the necessary tools, skills and experience to undertake this type of work. £350 or thereabouts isn`t a huge amount to spend to ensure your car is looked after in accordance with the makers guidelines.

Mike K