Greetings all...

The transmission in my '01 XJ8-L was rebuilt by AAMCO (don't laugh...was a friend's car before I got it) about 30000 miles ago and now the 3-4 is flaring/shifting hard. I looked at the ticket and of course they put the wrong fluid in it. I'm going to have a flush done and use the approved fluid.

Provided this does not work... Locally there is a 1998 parts car with the 5HP24. According to car-part.com and a couple of other sites the 1998 is a stand alone year. However, all the numbers on the transmission are the same as mine and according the the chart on the ZF site they are all the same from 1998-2003. The wiring harnesses seem to be the same as well. The fluid looks good in the salvage car trannie and I would like to have a backup in case mine goes south (people who ride with me are certainly shocked at the shift thud). Does anyone know about the cross reference on these and if there are any differences?

Thanks for any advise on the subject!

 

They are compatible.
The difference is in some internal parts, but you can put a 1999-2003 parts in 1998 case and it will work.

 

As Moscow sez....there update differences internally from the AJ26 to AJ27 engines.
Mainly concerning the uprated front 'A' clutch drum, bearing and circlip holding arrangements and these 'improvements' were introduced usually on TSB's or broken trans.
Otherwise they are virtually identical save a little tweeking in the gearbox ecm changing values....same ratios.

 

Most differences are in the valve bodies. Springs, valves and all that stuff.
Anyway, i've rebuilt mine tranny this march. I've had a brand new 5hp24 from Range Rover and mine tranny was dead. So, i've bought a gasket kit, disassembled both gearboxes and assembled mine back with all of the RangeRover internal parts, except output shaft and torque converter. Also i've used a RangeRover's valve body. Jaguar wiring connected w/o problems, everything runs great(shifts a little bit harder, but i just love it).
So... Virtually all of the 5hp24 (exc.AWD ones from VW/Audi) are all the same.

 

Awesome info. I can't help wonder if the transmission has already been changed in this car as it looks fairly clean. I'm going to do the flush on mine and see if the correct fluid will make a difference.

Provided I do get the transmission, should I get the TCM from the donor car?

 

Don't forget to change the filter. Also, drop the pan and if there's a lot of debris and metal... If there are - well in this case it's better to swap the trans. If the fluid looks fairly clean - do the flush, change the filter and oil pan gasket. Also, it's good idea to reset an adaptations by removing ECT and TCM fuses (3 5Amp fuses under the hood) for a 3-5 minutes.

No, there's no need to swap a TCM. Just reset adaptations as described above.

 

Let us know how the fluid flush works out. My transmission occasionally shifts roughly from 3rd to 2nd and 3rd to 4th on light throttle. Mine was also rebuilt about 30k miles ago and filled with the wrong fluid.

Does yours make any noises? Does it always shift harshly?

My harsh shift is almost totally eliminated if I keep it in sport mode.

 

Mine did ALL the same.
After some digging i've found that LTFT was up to -15 on both banks and STFT was -20 on both banks. No check engine, just light hesitation during acceleration. Found that it was caused by vacum leak via PCV hose on a right bank. Changed the hose, LTFT/STFT were back to normal and transmission shifts awesome again. Seriously, the harsh shifts may be caused by improper engine operation, even if the check engine light is not lit.

 

I need to check mine. My failing MAF caused my trans to slip out of gear when it was cold outside. I thought the transmission was going to check out at any time until I replaced the MAF.

Did your transmission occasionally bang into gear if you slow down to about 5mph and accelerate away? Mine seems to hang in 3rd gear as I slow down, then it bangs into 2nd when I accelerate. In sport mode, it won't get stuck in 3rd.

 

Yes, it did. Also, there was HARD bang in R when cold. Also, the RPMs were falling down way to slow after the cold startup. The milage was bad too.

 

Wow I have ALL of those symptoms! Thanks for the heads up! I thought the hard reverse shift was evidence of future failure.

 

Well. Check for a vac. leaks and may the fuel trims be with you

 

The valve body is what controls the shifting, so hard shifting is likely a valve body hydraulic fault (the valve body does have electric solenoids so it can also be electrical, just less likely). Just because AAMCO rebuilt the transmission, they probably did not touch the valve body. Its a known fault that the main pressure valve wears in the bore and can cause delayed or hard shifting. Its commonly thought that this is the main contributor to the dreaded A drum failure. Since you are going to change the fluid to an approved type anyway, go ahead and drop the valve body, disassemble the main pressure valve to inspect for wear (It comes apart easy enough and I used a large 8" c-clamp to compress the spring and put it back together). There's threads on here showing how. You could even take it to a shop or send it off for testing. But its a whole lot easier to replace a valve body than a whole transmission.