ZF5HP24 transmission in a 1998 Jaguar XJ8 Vanden Plas.
Builder replaced the failed B-Drum, valve body, hard parts and the torque converter on a ZF5HP24. So now the car engages into drive and reverse hard and vehicle lurches/lunges when doing so. When coasting to a stop the car bucks as it is downshifts thru the gears. Bucks harder when applying the brakes on your way to the stop light. Up shifting is relatively smooth but not near as smooth as it was before the drum failure. Sometimes, normal driving 30-40 mph, car seems to "hickup" like it cant decide on what gear to use. There is no slipping or a delay in gear engagements. Traveling at highway speeds, say 60-65mph, and i want to pounce the pedal to the floor it will kick down and engage with a very hard bang that shakes the whole car. Also does this when headed up a steep fast canyon. (this is similar to when the B-Drum originally failed and I was at a dead stop and in drive I increased the rpm when it "found/banged" into fourth gear lunging the car forward, skid the tires and the gearbox fault light comes on putting it in limp home mode, felt like someone hit me from behind, really rattles your chain.) I have done this carpet kick down before the rebuild many times and I remember it would do two quick kick down shifts but now it seems like its hoping over a gear and slamming into the next lower gear.
It does any or all of the above scenarios pretty much 90% of the time but sometimes it shifts into drive or reverse normally. After the kickdown bang it wont do that anymore until i shut off the engine. The downshift lurching is there all the time. Dosent matter if the outside temperature is 100 degrees or 25 degrees or when engine is warm or cold or driving in normal or sport mode.

The transmission fluid runs hot at 225 degrees.
Rebuilder swapped the valve body three times thinking it was a bore issue but with no change.
No codes or warning lights or messages present.
Idle is normal at 650rpm.
Trans fluid cooler in radiator is unobstructed as well as the lines per builder inspection.
Fluid is up to level assuming it was filled with the correct procedure per builder inspection.
Battery is at 12v but it is 4 years old.
No corrosion on pins at Transmission Control Module or Engine Control Module.
Throttle position sensor working tested with live feed code reader per builder.
Car does not have the flash acceptance capability on the TCM as far as i know.

Is this a torque converter problem that is causing the shifting problems (shifts bad when hot and or cold) and then it is just heating up the fluid to 225 degrees or is it the wrong fluid in there that just wont shift properly at all (shifts bad when hot and or cold) and is just heating up to 225 degrees cause it cant handle the mechanical dynamics of a more sophisticated transmission or is the trans fluid temp sensor faulty (hot or cold) telling the TCM to protect itself because it thinks the fluid is 225 degrees, But wouldent a bad trans temp sensor throw a code? Keep in mind that the car was already hot when the 225 degree reading was "discovered". builder did not put the reader on when the car was cold to watch the temp climb.
Torque converter problem. Could be it has just failed somewhere inside like a sealing ring or something, separated somewhere, or its just a cheap one that cant handle the demands of the ZF. The big question, whats causing this fluid to heat up?
Fluid problem? Before the original rebuild work was started I specified it needs to be ESSO/Mobile LT 71141 or Lifeguard Fluid 5 honey yellow in color. After the original rebuild complete with a "new" rebuilt or remanufactured Sonnax valve body I got the car back assuming it was the ESSO in the trans..... Took it for a drive and all the shifting problems were there right from the start. Took for another drive with the rebuilder sitting shotgun and the live feed code reader hooked up and he got the 225 degree fluid reading and nothing else, no codes, no flags, no lights. We did test the throttle position sensor percentage at 100%. Builder put in another valve body stating it was a problem with the bore(s) causing to much high line pressure. When I got back from a 2 hour lunch and window shopping around the city I noticed the "faulty/new/old" valve body on the table with red fluid all over it. I inquired he said "not to worry the red "spec fluid LT71141" that I used is not the problem it was the valve body." I thought LT71141 was yellow... Car got finished I took for a drive and exhibited the exact same shifting problems described above. Took it back again for the third valve body and a concern of the red "spec fluid" being used. Same story, red spec fluid is fine. So now three valve body's later it is still exhibiting the exact same shifting problems as it did with the second and first valve bodies. And it still has this red fluid it it, I know this because the pan gasket is now leaking slightly.

From time to time the message Stability Control Failure and the ABS light pops up in the display related to the left front wheel speed sensor input signal malfunction but his message was coming up long before the rebuild and subsequent shifting problems. Is this related?

Thanks again.

Jon

 

I fixed that ABS message by cleaning the inline connectors. There's one on each side at the front. Follow the cable from the hub, and the connector is just inside the inner fender.

As for the transmission, my suggestion is to request that they replace yours with one that works. Why are you trying to diagnose what they did wrong?

 

All I ever read about is the A drum failing.

 

Correction it was the A-Drum that failed. Thanks.

 

Sounds like the torque converter lockup is permanently engaged. That would account for both the hard shifts and the high temp.

 

Thanks Test Point, I sure appreciate your time with this.
Whats causing or has caused the torque converter to permanently lockup? Can the lockup situation be disengaged if so how or do I simply just need a higher quality torque converter put in? Whats your thoughts on this red fluid?
Thanks again.
Jon

 

I have never heard of a Dexron type transmission fluid that isn't red.

 

The ZF5HP24 box specifically calls for ESSO LT 71141.
Heres what i have read:
The Esso brand is now owned by Mobile and branded Mobile ATF LT 71141. You can use Life Guard 5 made by ZF, it is the equivalent of LT 71141 both honey yellow in color.
Does anyone know if there is a manufacturer that makes LT71141 spec fluid fluid and colors it red?

Thanks a bunch!

 

Many of us are using alternate fluids like Castrol Max Life European which is red. So far, I don't think there have been any failures reported after changing, but only time will tell, as the saying goes.

 

Hello RJ,

Cool thanks for the info, much appreciated.

Jon

 

I'm not sure how it would idle at stop with a locked converter. It sounds like it's "flaring" then grabbing.

Did they give you a full rebuild? ............. what did they charge?

 

Torque converter lock/unlock is accomplished by one of the valves in the valve body bolted to the bottom of the transmission. Operation is via an electrical signal from the TCM. If it is a TC problem, which it does seem to be based on your description, the problem could be the new TC, a defective valve body or an electrical connection to the rear of the transmission.

Meeting the LT 71141 specification means just that. As RJ said, many have used non ESSO/Mobile ATF without any reported failures that I can remember.

Surly you have some kind of warranty on the repair and obviously it is not functional at the moment. What is the repair shop saying?

 

I can see it causing rough shifts, but not high temperature. Surely lockup reduces losses, hence heat, in the torque converter?

I think the OP has a chronically overheating engine. Have you checked the coolant temperature?

 

Hello everyone thanks for helping in figuring this out.

@ yeldogt

Yes, a gentleman at work said the same thing. Engine would stall when put into drive or coming to a stop.... Rebuilt included: new A-drum, remanufactured valve body, remanufactured torque converter. Hard parts like clutch plates, seals, ect..... $3800.

Thanks for your help yeldogt.

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@ test point

I know bit of a merry go round huh? Torque converter causing the problem but what is causing the torque converters problem. He said he uses only quality parts which i believe so maybe the torque converter is ok which leads me to the valve body, he has put in three of them, cant imagine three of them would be bad. Possibly a electrical connection at the TCM or ECM, or to the trans itself, thanks on that, could be a bad ground somewhere but why isnt it throwing a code for a circuit malfunction. Maybe the TCM is bad? Would, could or does the torque converter unlock itself when stopping at a stop sign to prevent a stall?

Yea, spec LT 71141 should work just fine no matter what brand it is and should perform as well as ESSO or Pentosin or Lucas i would imagine.

Yes there is a warranty. The car is drivable trans is just not functioning properly... He thinks that its the TCM or electrical problem but hasent ruled out something inside the trans either because theres no codes being thrown which leads me back to possibly the wrong brand of fluid or a seal in there.

Thanks test point

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@ Mark SF

I wasent quite sure what to make of the temp was a factor but how hot is to hot to cause shifting problems i dont know. The trans fluid gets heated and cooled in the radiator so it should be roughly the same temperature as the coolant if not lower. Coolant temperature in the dashboard is normal temperature whatever that temp is idk.

The car has never boiled over or overheated and dosent have a hot feel to it. I need to do a little more research on just how hot is hot on trans fluid and engine fluid. I did order one of those laser temperature guns the other day. I report my findings on engine and trans pan temps when i get it.

Thanks Mark

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Everyone thanks again for helping me figure this out. I am going to look closely at all connections and grounds, find out exactly who makes the spec fluid, if that dosent work might have to crack the box open. If ya think of anything else please let me know.

Jon

 

Jon,

One thing you might want to research as you're trying to figure out this problem is the viscosity and Viscosity Index of the fluid your mechanic used. Many of the modern transmission fluids claim to be backward compatible with older specifications, but when you actually compare their specs with those of the older fluids, you will find that typically the newer fluids have lower viscosities at 40C and 100C and a lower Viscosity Index, which means the fluid not only starts out thinner than the old fluid, but thins to an even greater degree as temperature rises.

It is telling that ZF still recommends its LifeGuard 5 for its 5-speed boxes, and does not recommend its newer fluids, LifeGuard 6 or 8. Yet companies like Valvoline claim that their current fluids are backward compatible for all of those fluids, plus even earlier fluids like Dexron II and III. If anyone knows what fluid properties are optimum for each gearbox, it's ZF, so I would try to find a fluid with properties as close as possible to the original LT 71141 spec and not simply take the word of any company that their modern fluid is compatible.

It was only after using Dexron VI in our '93 with the ZF 4HP24 gearbox and then replacing it with Redline D4 that I discovered our torque converter had not been locking up properly. With the D4, I suddenly had engine braking and sport mode once again held lower gears much longer coming out of turns. D4's viscosity and VI are very similar to the old Dexron III and significantly higher than Dexron VI.

All that to say, it could be that your gearbox doesn't like the modern fluid your mechanic used, especially with new valves that were designed for a higher-viscosity fluid.

The only other thing I can think of that you haven't mentioned is the vehicle speed signal from the ABS/Traction Control Control Module, which is critical for both the ECM and TCM to produce smooth gear shifts. I assume any fault with the speed signal would trigger a code, but thought it might be worth mentioning just in case it might help to clean the ABS module connector and the wheel sensor that is referenced for the speed signal (off the top of my head I think it's the right front sensor but maybe it's another one).

Cheers,

Don

 

Hello Don,

Thanks for the info on the fluid. New "advanced" fluid for 2016 dosent go well in a car that is 18 years old. Makes sense...

Coincidentally enough I am having trouble with the left front wheel speed sensor showing intermittent input signal malfunction, see bottom of post #1, i think its the harness, hasest lit up for a couple of weeks though. If it is that simple ill kick myself.

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Ok, Im gonna check out all you guys wonderful suggestions. I cant thank you enough!!!!

Jon

 

Hello everyone,

Got the car to the builder. We were able to communicate with the car showing these codes:
P1797 CAN Transmission Control Module to Engine Control Module Malfunction.
(Jaguar specific codes says it is a Neutral Switch Circuit Malfunction.)
C1155 Wheel speed sensor. (Stability Control Failure and ABS icon illuminated in dash).
C1233 Wheel speed sensor. (Stability Control Failure and ABS icon illuminated in dash).
I think this is a bad bearing getting metal flakes on the WSS. I clean both front when i change the engine oil every 5000 miles and the message dosent appear again until close to the next oil change but the transmission still persists in hard downshifting after the cleaning. It has been illuminating long before the rebuild and subsequent hard down shifting in 4/2015. Bought the car in 11/2011
U1260 SCP(+) circuit failure.
U1260 SCP(-) circuit failure.
LTFT +7 (should be +/- 2 or 3?)
STFT +3 (should be +/- 2 or 3?)
Throttle Position Sensor reads 100% pedal to the floor. There is no kick down switch fitted.
P1260 Theft Detected Vehicle Immobilized.
There is on rare occasions of a no crank issue, Turn the key and it makes a click. Turn key off and on a couple of times and then it starts just fine. Been doing this long before the rebuild also.

Cleared all the codes restarted and hung around for 10 minutes with engine at idle...........
P1797 CAN Transmission Control Module to Engine Control Module Malfunction.
Calculated Load Value at Idle: 17.25-23.53
LTFT e+6.25
b+5.46
STFT -1.5
Same hard down shifting situation immediately persisted upon rolling out of the shop.

I read up on the P1797. Its a huge list of things to check and could be anything. If anyone can pinpoint just exactly what that one little fix is in one of these systems that is affecting the shifting that would be fantastic.

Builder assured the correct LT fluid used.
I read somewhere that 122 degrees is a little hot but not to worry about it.

Thanks everyone for your knowledge, expertise, feedback and especially the time you spend reading and answering questions for people on the forum.

Jon.

 

Hello Jon,
did you managed to fix the malfunctioning transmission? I'm asking, because my case is very similar, same symptoms after rebuild, same gearbox type.
Pawel

 

Good evening Pawel,

Some of this might be redundant.

Back in the long ago I took it back to the fly by night shop and on the way there it banged on kickdown and of course during the test drive i could not get it to bang again with the guy in the car. Left the car there, he said he drove it, couldent get it to bang like i described when in the canyon, looked at it, tore it apart again, swapped out the valve body, all which was probably BS but who knows. He never mentioned anything about the torque converter or the TCM. A week later i got the car back and it still did it.

Later I read somewhere that when the transmission gets rebuilt and/or before the transmission gets installed “something” needs to be pre tensioned or back tensioned, i forget what it was that needs this pre tensioning.

Would seem to make sense because it seems like “backlash” catching up to itself on kickdown/downshift and then WHAM! The feeling is more coming from the middle of the car under your *** and not in the back..

The only other thing i can think of if it is in the transfer case but i dont think so because it started the second the rebuild was done.

Climbed under the car with a big pair of channel lock pliers on the driveline that had absolutely no play from the trans to the transfer case. The doughnut that holds the driveline was tight and in tact.

Raised the rear and moved/rolled tire forward and backward about a inch in each direction before the tire on the other side moved so there was play in the rear axles but not as much to cause this much trouble i would imagine. I dont know how much play there should be in that area. Unless thats the answer IDK but leads me back to “the trouble started with the rebuild”. Plus i think it would have a huge lurching in random patters when driving if it was the rear end and it just didnt feel like it was coming from that area.

About the only advise I can give is to gently drive it out to your trans guy, plant him in the car and go up a fast canyon and let it automatically down shift or force a kickdown on the freeway dropping from 5th to 4th. And ask if he did the “pre tensioning” i guess. Maybe take a couple of videos one from the front seat and one from the rear seat of the bang before taking it to him. Id be interested in watching/hearing what yours is doing if you can post.

I cant imagine it being a transmission mount and the whole damn thing is lifting up and slamming itself into the underside of the car. But if that were the case it would do it every time on kick down or down shift. So were back to the torque converter or the lockup but it was never stalling.

To those entertaining a new trans… Just pay the extra $1k and go to Aamco or some other chain or pay $2k more for the dealer who knows how to do this pre-tensioning if there is such a operation.

So to answer your question.

I drove it for another 66,000 miles and lived with the banging until I lost compression in the great October 2020 resurrection (winter car) and it would not start, which I knew was ultimately going to happen since about 2018 when it started having a hard time pulling the hill I have to go up getting out of work. And the oil blow back. and the oil consumption, and the white smoke on startup. … So i bought the 07 you see in the thumbnail pic. I was sad to see it go. Personally I think the 98 has a better body build. Hopefully the engine and trans will be a better build on the 07.

I hope that was some help.

Regards,

Jon

 

What you read probably refers to preloading of the differential bearings and not the gearbox as there is no preloading (pre tensionong) there. As rebuilding the gearbox has nothing to do with the differential (I think you refer to it as "transfer case"), the clonking you had could only have been caused by something wrong in the gearbox itself, i.e. in its hydraulic and/or electric controls of the shifting. One typical example are "sticky" valves in the valve body caused by their wear.