So I posted recently this thread, where I had a fluid leak at the upper coolant connection due to loose fitting:
https://www.jaguarforums.com/forum/x...-miles-224072/

I performed the fluid (Mercon SP)/pan/mechtronics seals replacement, and all went well enough. The Jag transmission was immediately happy and worked flawlessly for 3 days. Not a single issue.

Day 4, it threw the transmission fault about 7 miles from home on the highway, got off the exit, BARELY limped across the overpass with major slippage, and into a gas station parking lot. Turned off for about 8 minutes. Upon restart, it worked again the rest of the way home (about 5 miles, the last 2.5 up 5% grade), though was not terribly happy to do so. No Transmission Fault that time though.

After parking (a little nose down) and sitting 10 minutes, the transmission threw the fault light immediately upon shifting, you could hear/feel it engage lightly when shifted, but would not move. Total slippage with a light buzziness to it.

Externally there were NO leaks and I appeared to have buttoned it up nicely. Nothing loose or leaking. I had been very careful with the mechtronics unit, replaced the four tube seals (stuck out about 1/16th inch, I imagine that was correct) and front square seals. I torqued the proper bolt pattern about 7-8 ft-lbs. Pretty sure I did nothing wrong there. The electrical connection snugged into place and locked down without issue.

The battery happened to be near death, so I replaced that. I also recalled mildly messing up the fluid level replacement so I jacked it up level and went through the proper fluid check, adding about another quart in the process.

Set her back down, restarted (runs fine), shifted into reverse...No joy. It would occasionally provide a little push, but only enough for me to get the car turned around and into a better position for towing, but otherwise total slippage.

Throughout the ordeal I only managed to pull 2 codes prior to the fluid change (nothing since then), though my OBD2 reader is cheap and only gets P codes. P0729 P0783

WHAT SHOULD I DO NOW? Is it time to tow it in to the local Jag shop? It has 149,500 miles on it. When I did the fluid change, I only got about 2 quarts out of it after it had leaked badly a few days prior to my planned fluid change. The fluid was thick, brownish, but did not smell burnt (practically no smell at all, which was why it was hard to know it was leaking to begin with).

 

Try checking the fluid level, be sure it's at the right temperature.
Too hot could leave the level too low, it can't shift right low on fluid.

 

Thanks for the advise. I have done that again, but with the same results. The current problem isn't shifting issues, but it isn't engaging at all (though it sounds and feels like it goes into gear, it doesn't feel like clutches are engaged). It was working for 3 days perfectly following my fluid change, then suddenly it is now slipping badly to the point of being unable to move in any gear.

What could be the potential issues at this point? I have read where bad coils/plugs could cause trans issues, but I am not currently witnessing anything like that. Can engine issues actually cause the trans to slip badly? Is there anything I can do myself, or do I need to take it to the Jag shop at this point?

 

Erik; Have you verified the shifter cable bracket securing the cable running from gear selection mechanism to the transmission shift lever is properly attached? The bracket is attached to the left side of the transmission and multiple forum members (myself included) have found this loose. Excessive movement here causes shifting issues. Probably a long shot but who knows until you check.

Best Regards, William

 

Yup, in fact I had that very issue and the nuts happened to have fallen right under it while sitting in the driveway :-)
I reinstalled using lock washers and they are intact and tight.
So far I have found one other forum thread with the same issue I am going through, where they ended up low on fluid from a leak, and upon replacement has the slippage issues. They ended up still being low on fluid, and were discussing air in the coolant lines.

I may still have a fluid issue. If the fluid is initially evacuated via the coolant line (my upper connection had become very loose somehow), how long could it take for any air to bleed itself out of the system?

Another thing I may have done in error (due to being old school) is not having the trans in PARK, rather leaving it in NEUTRAL (old cars checked the level "hot idle in neutral")., and I hadn't bothered to have the A/C or lights on. I will give this yet another try. Just to make sure I had done this right otherwise:

1) Level the transmission based on the pan bolts/rim, not the pan bottom.
2) Start car, run through Reverse and Drive for 5-10 seconds each, THIS time I will leave in PARK, not Neutral (how much of a difference can this make?)
3) Let sit at idle for maybe 10 minutes then check pan temp with surface temp setting on my IR thermometer, noting that it will be 2-3 degrees lower than actual fluid temp (good enough?)
4) When temp has reached 35 ish (32 ish on my method), open side drain plug (no fluid should be coming out at this time)
5) Continue to monitor temp until it has reached 40 C (37 - 40 my method)
6) If fluid starts seeping out then it is full, reinstall side drain plug. If not, quickly pump some more in there, let come out to small stream, plug it back up.

Question: Do I need to run the trans through the gears again at any time or is just the first time the only one necessary?

 

My thoughts...

Make sure vehicle is level, not so much the transmission pan.

I also run the gear selector through 2 - 5 and drive and reverse, neutral then park a few times as well.

AC running... helps warm the trans fluid faster.

At 40 deg C you should have a steady thin stream of ATF coming out of the fill hole.

If you dont have software to monitor temp (and it sounds like your low) I'd pull the plug at 36 deg C and pump a bit of fluid in if nothing comes out when you take plug out.

Finally, after installing the mechatronic sleeve did you measure distance between the TCM harness to trans case when fully locked.

Spec is 2.5 to 3mm, no more...

Any further means you didnt seat the mechatronic sleeve in correctly and yes, the white tab on the TCM can/will fully lock with the sleeve not fully inserted leading to leaks and incomplete connection to TCM. (I've done it!)

Sounds like your still low on fluid though.

Should of got at least 6L out.

If only 2L came out then you might have been 4L short with the leak. Anything shy of 2L short these transmissions go nighty nite...

Good Luck

 

If the sleeve is not quite seated enough (I will verify the distance too), shouldn't I be able to pull it out again easily enough? I have the CTSC pdf now for reference.

It sounds like I need to go through this whole routine again, with the exception of dropping the mechatronics unit. I imagine it would be worth the expense to ditch the fluid since it has been mixed with the original LifeGuard too.

So they really want the vehicle leveled (such as down the rocker panel/frame), not the trans?

 

Regarding the sleeve if it is not seated properly you have to drop the pan and release the white tab.

I find you need to apply equal pressure on the sleeve when installing it and lube the o rings with petroleum jelly. (Instructions say trans fluid - I used the plumber's lube for o rings on my last sleeve change - works even better than Vasoline)

I used a small cut piece of a 2X4 flush and press fit it in with a crow bar. Go easily.

I find if you try and press it in by hand you dont get it in all the way, especially if the car is on jack stands.

Could possibly get it in if car is on a lift and you can visually see it.

Yes, I believe in the instructions it states "ensure vehicle is level".

I measure at the rocker panel between the front and rear door. If its level your good.

I wouldn't drop the mechatronic unit. That part sounds like your on the money.

Most important guidance I can offer...

If you have to drop the pan try and capture all the fluid to see how much you get out and measure it.

If between 5.5 and 6.5L - sounds about right.

Anything less than 5.5L - your low.

Make sure you get about 5.5 to 6.5L back in regardless.

Should take 3L right off the bat upon initial fill before starting the car. Start car, go through gears. Pop off the cap (while car is still running) should take between 2 and 2.5L more until you get trickle - cap it go through gears again pausing 5 - 10 seconds between each change.

At 36 - 37 deg C - pull cap off. You should be able to add just a bit more (.5 to .75L) Add it slowly.

That'll get you to 40 deg C and a slight trickle spec.

You want a thin trickle not a steady thick stream..

Cap it and your done.

These trans can be tricky to refill.

I've done this about 4 times...

Hope this helps.

 

After spending 4 hours again last night after work, being meticulous with my steps, I have determined that I did a fine job the first time, but something else has gone wrong. I did manage to get the sleeve in by hand the first time fully seated, and removed 6 litres of fluid on my second verification refit/refill. I got about 6 litres back in, and made darn sure the connector was seated, this time with some leverage. No bent pins or issues on the plug side, everything went smoothly back together.

Upon restart of the engine to run through the gears and idle in park, it threw the Trans Fault. I finished it up anyway. From under the car while refilling the additional fluid while warming up, the trans made unhappy sounds like pump bearings going out. It quieted somewhat as I topped up the fluid and closed it up at 40C, but never really went away.

After all was done, and I stopped and restarted the car, there was no trans fault immediately when I shifted into D and it pulled forward about 15 feet (yeah!). I then put it in reverse and as soon as it started backing up, trans fault came on and it started slipping badly again. I got it parked in front of the garage nose forward so it can be easily loaded on a flatbed. Off to the Jag shop after all.

The engine runs great and no codes are thrown. The car is super clean (no corrosion or rust or dirt really, other than a slightly leaky oil pan), so I will be getting it fixed one way or the other. I do need to stick to a budget though, so will be taking the least expensive path forward. I was thinking I would have the shop run diagnostics on it first and see if they can determine the problem and if it is reasonably repairable. Otherwise I will go with a good used trans replacement.

 

That sucks. Used trans replacement (w/ a low mileage unit) will probably be your most cost effective option.

Rebuilding these trans run between $5K - $7K.

 

If you get a used transmission I suggest that you completely drain it and I mean completely. Noting the color of the fluid for posterity. Install your already new pan and mechatronics sleeve.

When installed and obviously before running the engine fill it as much as poss then do a refill as usual.

I have only ever done a complete flush of my transmission while it is in the car so not 100% sure you can drain the blighter when it is out of the car so
I am assuming this is possible with a pump?

 

I will have to rely on the Jag shop to make the best decision concerning the process in which to reinstall a trans, but will be sure it is "refurbished" properly. These Jags are getting ridiculously lower prices lately so it is tough to validate high dollar repairs.

 

Jag shop is going to try and talk you into a rebuild.

Not worth the investment as you mentioned.

Good luck though...

 

My XJ8 did that at 52k. Took it to Ampco. they rebuilt it for $4,300 and now at 60k it's still running fine. Good luck.

 

Ok Bagheera just got to the Jag shop. I think I can trust these guys. I already had a good conversation with them, and they were like "I would first suspect the valve body seals, because we don't have to replace or rebuild very many of these. The seals failed in a few we had done, that was all. Since you replaced them already, I will diagnose otherwise and not tear into that. Sounds like you did the job right." The car worked perfectly for 4 days before slipping.

So, my only thought was if the Chinese aftermarket kits have faulty front seals or bad pan fluid draw seals or something like that. I could not find any bad reviews though in Amazon about them. Anybody else know about the Chinese pan/seal kits?

 

Most of us use the genuine ZF kits. You may be right as to the chinese kit leaking or filter not allowing correct flow. With process of elimination as to what parts were changed, the new parts may be causing the issues, assuming that it worked perfectly prior to the 1st drain and fill. I didn't see in your first post if you did the service as a preventive measure or if you were having issues with the transmision?

 

Actually the trans was questionable when we first got the car at 120k miles, with oddities such as Reverse taking around 3 seconds to engage, and "sporting" behavior was not appreciated (hard to explain but it was not right). My lack of knowledge of this trans and ignorance of fluid not being red and smelly (apparently still had the original fluid), lead to a slow leak that eventually became a torrent one day (top coolant line nut somehow came loose).

In short, I believe the trans went from 0-150k miles with ZERO maintenance. Thus we determined that although the 6HP26 is rock-solid, without maintenance (not even fluid level checks...the miles just got away from us I guess) it seems to have a life span around 150k miles.

We got a super clean used trans from a 100k mile Jag for $650 (same 2005 XJ8 N/A), reconditioned it with fresh valve body seals, pan kit and fluid, flushed cooler, and new coolant lines. Not cheap as the final bill was $3300. It did include new motor mounts, and I have a 1 year guarantee on the trans and $650 toward labor costs (extended warranty thing).

So now "Bagheera" drives better than ever (since we got him), and ALL shifts in ALL conditions are smooth and flawless. :-)