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1992 XJ40 w/160k+ miles, many previous posts about this car.Finally narrowed down "lurching,missing"problem at steady highway speeds as the torque converter lockup kicking in and out. Read a post on a BMW forum about same problem with same transmission. Owner there wired in a electrical switch to manually engage/disengage the electrically controlled solenoid, solved problem for now. Talked to local Transmission Guru who Local Jag and BMW shops refer to. They said since solenoid is elect. controlled, almost always problem is connection corrosion, break in wires or ECU related. I can find no visible wire problems, but where wires attach to the tranny unit is sealed with 6 or so torque head screws holding unit together. That assy. also has a removable dust boot that when removed shows a 1/4 square "socket" that looks like an adjustment port. Before I open it up, can anyone tell me what I am getting into?
6 wires going into this "thing", am hoping for fixable corrosion. This car is my sons daily driver to local college, no other MAJOR issues, so I hate to muck it up not understanding how it works. Any advice??
1992 XJ40 w/160k+ miles, many previous posts about this car.Finally narrowed down "lurching,missing"problem at steady highway speeds as the torque converter lockup kicking in and out. Read a post on a BMW forum about same problem with same transmission. Owner there wired in a electrical switch to manually engage/disengage the electrically controlled solenoid, solved problem for now. Talked to local Transmission Guru who Local Jag and BMW shops refer to. They said since solenoid is elect. controlled, almost always problem is connection corrosion, break in wires or ECU related. I can find no visible wire problems, but where wires attach to the tranny unit is sealed with 6 or so torque head screws holding unit together. That assy. also has a removable dust boot that when removed shows a 1/4 square "socket" that looks like an adjustment port. Before I open it up, can anyone tell me what I am getting into?
6 wires going into this "thing", am hoping for fixable corrosion. This car is my sons daily driver to local college, no other MAJOR issues, so I hate to muck it up not understanding how it works. Any advice??
Hi Shelby676,
I believe your '92 has the same ZF 4HP24 transmission as our '93. Below are links to photos that may give you an idea of what you'll find. Also, the eBook at the Jag-Lovers forum has an excellent diagnostic procedure for the ZF transmissions at this link:
I also have the ZF service manual in pdf form - PM me if you'd like me to send it to you.
Aside from checking the electrical connections and the solder joints and contact arcs in the rotary switch, you can check the electrical connector at the TCM and open up the TCM and inspect for starved or cold solder joints - I found a bad joint in ours that was the cause of our most recent Limp Home Mode.
Thanks for the reply and links to pics. I was looking at a different set of wires and Switch of some kind just below the pictured cable. I will dissconnect and visibly inspect connection tonight. The TCM is behind the Right side Knee well area, correct?
The TCM is behind the Right side Knee well area, correct?
Hi Shelby,
Yes - on our LHD cars the TCM is behind the right-side knee bolster (or "underscuttle" or "dash underpanel," depending on which Jaguar reference manual you are reading). I'm adding links below showing how to remove the and identification of the major components behind the panel:
Hello !
I have the same problem as OP : when the car is warm, after 10 km or so, when I reach about 82-85 km/h, the torque converter lockup kicking in and out.
It is ver annoying.
This morning I changed the transmission fluid with its filter underneath, but still the same.
Did somone already fixed this problem on 4hp24 transmisison ?
I have the same problem as OP : when the car is warm, after 10 km or so, when I reach about 82-85 km/h, the torque converter lockup kicking in and out.
It is ver annoying.
This morning I changed the transmission fluid with its filter underneath, but still the same.
Did somone already fixed this problem on 4hp24 transmisison ?
Hi Carmelo,
Did you use a fluid that is a true equivalent to Dexron III? Most of the modern transmission fluids have a viscosity that is too low (they are too thin) compared to Dexron III. One fluid I know of that is appropriate and should be available in France is Mobil 1 ATF.
Did you set the fluid level exactly at the HOT or MAX mark with the transmission fully hot? A good way to do it is to drive the car for 20 minutes or so to get the fluid fully hot. Park on a level surface, set the hand brake, hold the brake pedal, leave the engine running and shift through all gear positions, PRND32, holding each position at least 3 seconds. Return the gear selector to Park, then check the transmission fluid. It should be exactly at the HOT/MAX line. Even one pint too low or too high can cause problems.
The level is right between MINI and MAX : is it too low ?
I had theses lock in - out problems before (it is why I've done the flush) but less frequently.
I just took a quick look at the Material Data Safety Sheet for Total Fluidmatic ATX, and based on the published viscosities, it does appear to be a suitable replacement for Dexron III.
I'll ponder your symptoms. Your assumption is that the torque converter is locking and unlocking. Can you describe exactly what is happening? Is the engine rpm going up and down? If your car has Sport mode, have you tried engaging or disengaging it?
When you get a chance, please visit your User Control Panel and edit your signature to include the year, model and engine of your Jaguar so we don't have to scroll back to your first post to be reminded.
Ok. Now I am TOTALLY confused. I am still also having this same problem after changing my fluid 3 times as referenced in my thread. Is the 94 trans controlled differently than the 92???
Is the 94 trans controlled differently than the 92???
Hi Jerry,
As far as I know, the Transmission Control Modules for all of the 4.0L cars with the ZF 4HP24 were similar (made by Bosch, if I recall correctly), and the final supercession for the replacement TCM for the '90-'92 and '93-'94 cars were the same part number. However, the engine management and Engine Control Modules were different, and the ECM, TCM and ABS modules work together in orchestrating gear shifts and transmission operation.
I can't remember whether you are working on a '92 or '94, but if it's the '94, have you looked at the transmission diagnostic procedure in the Jag-Lovers XJ40 eBook by John Ping? I think it is only for electrical faults that illuminate the transmission warning light, but it might be helpful if your issue is with the control system rather than hydro-mechanical inside the gearbox.
I just took a quick look at the Material Data Safety Sheet for Total Fluidmatic ATX, and based on the published viscosities, it does appear to be a suitable replacement for Dexron III.
I'll ponder your symptoms. Your assumption is that the torque converter is locking and unlocking. Can you describe exactly what is happening? Is the engine rpm going up and down? If your car has Sport mode, have you tried engaging or disengaging it?
When you get a chance, please visit your User Control Panel and edit your signature to include the year, model and engine of your Jaguar so we don't have to scroll back to your first post to be reminded.
Cheers,
Don
Hi Don !
I have already set my signature with car model and year, and I see it in each of my messages.
When I reach 82-85 km/h (some times later, depending on road configuration and right foot weight), and if in Sport mode it's rather at 95-100 km/h I obtain :
- no up and down engine rpm
- the car shocks a lot, like the engine was stalling and restarting again, twice per second.
- as long as I don't release or push the accelerator, I'm "able" to keep the car jerking. As soon as I release accelerator or push it down, even a little bit, the symptoms immediately disapear.
Here is a little video I made yesterday. The problem occurs at 0'41'' (we hear the jerkings, but not see it because of my iPhone optical stabilization ) :
I can't tell from the video, but one possibility is that your propshaft/driveshaft center bearing surround has weakened and an oscillation occurs at that particular engine rpm/road speed. The transmission mount and flexible coupling between the propshaft and differential can also contribute to these kinds of vibrations at specific speeds.
Torque converter lock up problem
) :
