First, a little background to set the scene. I have an ‘03 XJ8 with 118K. Previous to my ownership (1 year+), it was owned by a friend of mine who took great care of it. I bought it at 99K and it’s been a good car up to this point.

I am very farmiliar with the issues these models can have with the A drum failure and to prempt that, I serviced the transmission in Sept ‘17. I have a friend that works on these at Ericsons in CT, so it was done right. We drained the fluid and dropped the pan. There was zero metal filing in the pan and the magnets just had a fine metallic paste on them. We filtered the old fluid and again, found zero filings. We checked the speed sensor, that sits next to the A Drum and it too was clean of any metal shards. We did the upgraded valve modification and changed the filter. Filled with proper ZF brand fluid, did an ECM reset and road tested it. All good.

Fast forward 7 months and I noticed that the transmission was beginning to shift a little funny. It was holding gears and then shifting hard. Sometimes it would bang into gear. Eventually, it would throw a gearbox fault and go into limp mode (usually in third).
It seems to run fine when First started and will start to act up after it has warmed up. The last time the tranny started banging into gear, I actually got a check engine light. It went away after three key start cycles. I have done a hard reset, but that hasn’t cleared the problem.

I’m looking for a little help in where to look next. I really don’t think it is an issue with the transmission and I’m beginning to lean toward a battery/electrical issue. Before I start throwing parts at it I’d take it to a mechanic, I’d like to explore some other possible causes. I restore British sports cars as a hobby and know my way around a tool box. I don’t have the CATS software, so I may need to go to my mechanic who does.

Any ideas, suggestions or prayers would be greatly appreciated. Thanks in advance.

 

Did you flush the old fluid and replace? With OEM or equivalent? Before looking elsewhere I would at least check the fluid level. Your issues sound to me to be transmission specific.

The classic A drum failure symptom is hesitation when shifting into first from reverse or park, then a bang. Even noticed when coming to a stop and then accelerating before the transmission has completed the downshift to first.

The work you performed should help prevent A drum failure, but it can still happen.

 

 

Did you check for possible misfire(s)? Misfires can also cause the TCM to place the gearbox in limp mode and display the 'Gearbox Fault' warning on the instrument cluster.

Are there any DTCs stored? If so, post them here.

 

I am joining in this thread because I want to know how this turns out. I am getting a gearbox fault, no traction control and limp home suddenly while cruising in traffic in like third or fourth gear. Shut it down and restart no issues but only for about half a mile before I heard not a bang but a gentle thunk in the rear. Coasted to a side road. Restart cleared it; I assume temporarily.

Fluid was changed by a qualified tranny mech who has done ZF gearboxes several times a month. At the time, he said he saw no shards, filings or other issues. It has run smoothly for exactly a year. Mass air flow sensor was replaced then. And gear faults, etc cleared then and been flawless.

 

Update 6/17: Having got frustrated driving the car, I put it aside and rode my motorcycle while the weather was good. Left the car in the garage and did some research.

I am going to assume that the transmission is NOT failing as the symptoms indicate, but have decided to jump into the land of possible electrical gremlins. Took the car to Advanced Auto and had them run a full battery test on it. Here are the results...
> Static Voltage: 12.44V
> CCA: 595 (battery rated at 730)
>Cranking: voltage drops to 11.2V
>Alternator output: Load-13.53V No Load-13.78
They consider the battery to be good, but it could be charged. My thoughts are that the CCA, while in spec, may be low for what the system needs. Does anyone have any thoughts on this???

I have done a hard reset on the ECM and put the battery on the charger overnight. Will have it retested tomorrow. A new battery with a three year warranty and 920CCA is $160. Might consider just replacing it as a cheap fix to guarantee that it is not the problem.

Input please!! and Thanks!

 

i just bought a 2001 xj8 with the same issue, was told it was after powerwashing the engine but took that with a pinch of salt and price was allowing for a box swap.tried new battery, cleaning tcm contacts, box contacts,reseting, hard reseting plus checking oil level.seemed high today when i checked it but may have been higher than recommeneded 30/40 as got a lot spill out when i opened plug when engine running.couldny get plug back in quick enough as kept burning my hand on the exhaust lol.i also changed and flush the coolant as it was all water only as a few hoses were broken and had just been topped off id say...

dont know wheather to try a fluid filter swap as ite200 wasted if the A DRUM IS DEFFO GONE ???

 

 

Hello there, did you ever figured out what happened?