Hello all,
It's been a while since I posted on here but the Cat sure likes to keep me broke and busy. (04 XJR)
For a week the car has been slipping when changing from 2nd to 3rd gear but only when cold. Once the car warms up no more slipping. If I drive it gently during this warm up period there is no slip. If I drive not so gently when not warm the slip will occur throwing a P0782 code.
Now for the history:

1. Replaced pan and fluid 6-7 qrts if I remember, back in Nov 2015
2. Replaced all plugs as well in Nov 2015
3. Replaced all coils summer of 2016, Airtex Wells, seem good quality as others have used these no problem
4. About 2 months ago the rubber trans hoses gave out when I raised and lowered the engine to replace engine mounts and AC compressor. I replaced the rubber sections with hydraulic hoses from NAPA & double clamped them. Replaced less than a quart of fluid during top off process. I posted previously in this regard as I thought that maybe I misfilled the tranny but I was just being a hypercondriac and the trans was shifting fine. Anyways, I checked the rubber hoses this weekend they're still solid no leaks.
5. I drained and refilled the tran Sunday about 4 quarts is what I got out and in. The fluid that came out was dark blackish red. I've been using Mercon SP for all my fill ups. There was no debris or metal shavings in the old fluid, however I did not pull the pan to inspect the magnets.

That's where I'm at folks. I'm hoping that there's still old fluid in the system that's causing the slip and will do another drain and refill. Or I'm also hoping that I'm actually low enough on fluid that causes the slip while cold but not once it's warms since the fluid expands; the mornings here in Texas are significantly cooler the last 2-3 weeks which I'm hoping is why it slipped now vs 2 months ago and I'm messing up the refill process. Hope it's not worse than that. From what I've been reading over the years on the forum it seems to be rare to see worn clutches or mechanical issues with the ZF tranny. I have also never cleared the transmission adaptations for this car. I do have SDD but will admit I dont have the Trusted Mongoose but the kit sold by British Diagnostics. If anyone knows the instructions on how to reset adaptations it would be great. Let me know your thoughts guys. As always thanks in advance.

 

Did you do the refill at 40 degrees C so that fluid dripped out of the fill hole with the car level?

There is still old fluid in your system since the capacity is about 10.53 quarts including the cooler. So after the 1st change you would have a mixture of old and new.

 

Thanks for the reply Jackra.
I had a stream of fluid coming out at 36C when I capped the tranny. I also selected R,N,D and 2nd for 4 seconds each once on the shifter. I did rush through this part of the fillup procedure to avoid going over 40C. Maybe I'm not giving the tranny enough time to really circulate the fluid? Should also shift through the gears more than once?

Also, I took level readings at the subframes on either side of the transmission and the crossmember in front the steering rack. Anyone know if there are better spots to check level. Maybe next time I'll measure height from ground to jack points?

 

I think you are ok on the leveling BlackKat.

The 4 degree C difference affects the volume of the fluid obviously but I do not know how much overfill that would be and whether it would be significant.

I do think you need to go thru the gears several times.

Its a hassle because you are always wondering if you have gone above 40 and if you rush to fill you get burned on the exhaust I know.

When I did mine I found I needed a top up after driving around a bit.

Read this: https://www.jaguarforums.com/forum/x...ncerns-116280/

 

Lots of information re ZF g'box in this recent link on this forum:

Everything about your ZF 6HP26, 6HP19, 6HP28 transmission issues | BMW LOGIC7

 

Thanks Merion. I nerver replaced the square bridge seal when I replaced the pan. I'll give a try this weekend, fingers crossed I dont snap a pan bolt.
Hoping that's the most I'll have to do. According to the link seems like their solution to everything is to replace solenoids or rebuild the valvebody! Yikes!
Anyone replace these solenoids before?

 

I have not doing XJ trans. but I thought all trans. had the solenoids, how about cleaning the solenoids?

 

Well gents,
I went ahead and removed the mechatronich valve body to replace the bridge seal and the 4 sleeve seals. I should've done these the first time I replaced the trans pan but was to scared to mess with it at the time. It actually wasn't that bad of a procedure. Upon first inspection of the seals they didn't seem worn and thought I had wasted my time and hopes. Upon comparing the used seals with the new ones I regained my hope. The seals all seemed to have shrunk in size. Notice the attached pics. I bolted everything up and started the refill procedure only to realize I'm short on fluid. Rather than pump what was in before I'll just buy a couple quarts from the store tomorrow. Really hoping this is it. Keep your fingers crossed for me!

 

Also, can anyone confirm where to place a level to check if the car is flat? I've been placing a level one the sub frames on either side of the transmission but the car seems too high on the rear with this measurement. I'm not sure to use the pan as a level because the pan to me seems to slope down towards the rear but the pan bolts don't. Maybe my eyes and lack of sleep are playing tricks on me. Sigh.

 

I found this on a ( ). This is what I assumed when I flushed my tranny.

Hi, is it the car that should be level or the transmission flange? When my car (Jaguar S-type R 2003) is level the transmission is inclined, maybe up to 5° backwards (CCW), and the filler plug is placed towards the rear end (in center lengthwise would have been better;-)), consequently the amount of oil in the transmission would be less compared to filling a level transmission. A guess would be maybe ½-1 liters in difference. Now I would assume the installment in different cars may have different inclination and therefore they would end up having a different amount of oil depending on this. As I can see it, this has a much larger influence on the amount of oil than being in the correct temperature range.
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ZFServicesNA
ZFServicesNA
1 year ago
+Steven Rovs Hansen When we say the fluid change should be done with the transmission level, we are referring to the vehicle not being on a hill or with jack stands only lifting the front or rear of the vehicle. If you raise the vehicle on a level lift on level ground and the transmission is off by a couple degrees due to the position it sits in the vehicle then this is not a big deal. You could use shims to get it as close to level as possible but a couple degrees off won't hurt. For additional questions, please reach our technical service team at 800-321-0784.
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Well gents, I head the transmissions adaptations desert and the TCM software updated Christmas week. I noticed that the new software holds the gears a lot longer while cold than before. Also, the torque converter lockup while cold is a lot smoother and less noticeable, the rpms still move up and down but a lot lot less and only noticeable if I look at the tachometer. Unfortunately she still slips from 2nd to 3rd while cold. Last couple of days I've gotten gear box fault in the morning when shifting from park to D or park to R but only in the coldest weather we had 15-25F. I believe the solenoids are dying and am looking at rebuilding or replacing the valve body. I'll keep you guys posted.

 

Not sure if I overlooked the info if it is somewhere in your post, but what's the mileage of the transmission? Oil is good, but at a certain age the clutches and torque converter just wear out and there is no way to "glue" them back together just with new oil or mitigate lack of mechanical function by software updates.

I feel with you, my transmission has similar issues now (more or less acceptable after 317.000km) and I prepare to bite the bullet and have it completely overhauled at a quite good ZF service point not too far for approx. 3200€.

Flushing the box and and reworking the mechatronic has helped somewhat, but in my case the rough reverse and slipping 3rd are a clear indication that after a long and fulfilled life the bell tolls for at least the B-clutch, and most likely also the torque converter, given then overall acceleration performance that has significantly deteriorated over the last 5000 or so km. Every further attempt to still get away with cheaper attempts to help the trans will in my opinion be more expensive eventually.