Wondering if I should do a full flush or just change the fluid and filter in my transmission.

Thoughts on this?

Also, anyone have any preferences on fluid types?

 

Generally a flush is considered best, but......

There are some cases (rare) of the flush process...if you're talking about having it done prefessionaly with a flushing machine.... stirring up gunk inside the trans and creating a problem where none existed before.

If unsure as to the condition of the trans then drop the pan for a look-see. What you see in the pan can tell a story. A thin layer of sediment at the problem is normal-ish but I've seen some with 1/4" thick layer of goo and gunk.....and even chunks of clutch plate material. Bad news.

So, drop and clean the pan and replace the filter. Refill, drive a few miles, drop pan again (or simply drain it, if yours has a drain plug) and refill. Repeat the drain-refill three or four times.

I might add that replacing the filter usually isn't even required in most cases. If a trans filter is clogged then you have bigger problems. But, as long as you have the pan down, it would be a shame not to replace it while you're at it. What the heck, right?

Cheers
DD

 

Opinions will vary.... boy will they vary

But I avoid "flushes" as I personally think flushes run the risk of knocking large amounts of gunk free that can end up in other places that transmissions don't like.

Do a "Google" on the subject and decide for yourself though. There will be no shortage of posts on this subject

However, what I do:

- pump out as much of the existing transmission fluid through the dipstick tube as possible, and then replace with clean fluid. Be sure to follow the proper procedure to verify proper fill.
- drive for a day, or until you have time to drain and refill again. Maybe in a day, few days, or next weekend. It really doesn't matter. You just want to give the transmission a chance to circulate the new fluid fully.
- pump out another round of fluid, replace, drive... and repeat until the fluid comes out essentially "clean".
- Drive it again for a while, then plan to pump out the fluid one last time (or drain via drain plug), drop the pan and replace the filter. Refill and you'll be good for the next service interval.

As far as the correct fluid. I haven't yet looked at what Jaguar specified for the 4L80E that is in the XJR (in my case), but I suspect it is(was) Dextron III. Since GM no longer licenses Dextron III and it has been superceded by the fully synthetic Dextron IV, I would replace it with Dextron IV.

I don't recall if the XJ6 has a different transmission than the XJR. If it does, I'd go with the recommended specific transmission fluid, or an officially licensed equivalent.

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I dropped the pan, changed the filter. I refilled the oil through the transmission dip stick hole by using a garden pump sprayer. This reminded me that I also can vacuum/remove the oil through the same hole and refresh with new oil. I just happened to have a vacuum pump for this job..Lately, reading these Jaguar posts which makes me pay a whole lot more attention to the Jag.

 

My problem with a "normal" change has alway been mixing different fluids; if you are not putting in exactly what you take out who knows what you end up with in the trans after the old and the new are comingled...

With a flush the pan is dropped first and presumably cleaned; hopefully most of that old "gunk" has ended up in the pan

 

When I changed mine out with Valvoline Full Synthetic ATF I dropped the pan, cleaned it to a shine and in the process could barely find any particles in the pan which was good to see. if you "flush" or not I don't think you can clear out what's in the torque converter so the fill drain and refill multiple times method after some driving seems the easiest. If you take your filter out to put a new one in cut the old one to see if any particles are inside.