Hi all! This is a long shot, but my Jag has some strange transmission issues. I know, I know, another one of these threads.

My Jag is a 1998 X308 4.0 with the ZF 5HP24 afaik. I bought it in december with 420k kilometers on it for dirt cheap and I honestly didn't expect it to even make it to june. But here we are and it has been basically flawless. Once in a while, it has had some weird harsh shifts, especially on inclines. Luckily I live in the Netherlands, the flattest country on earth, so it only happened maybe five times in the six months of ownership.

But yesterday, it was extra weird. I drove it to work and it kept engaging and disengaging randomly. I'd hold the pedal in one position and it would just lose and gain drive constantly. Not harsh or anything, but definitely weird. I was really worried and already looking up transmission rebuilds, then I decided to try it again today and it worked flawlessly... It has had this same issue véry slightly every once in a while, where it would subtly hessitate when holding constant speed, but never this bad.

So, TLDR: Transmission randomly picks days where it engages and disengages at will at constant speeds. On it's good days (99%), it shifts beautifully and smoothly. What could it be? I have a trans fluid swap planned for this month anyway, but could this point to more than just lack of fluid/old fluid/clogged filter?

 

Here's a couple of videos to review.... this guy Gary Ferraro has a number of videos on this transmission.



Here is the upgrade part he is speaking of...Transgo Pressure Regulator Valve for BMW, Jaguar, Land Rover ZF5HP24 Trans (5HP24-PR).
This tends to be a tough item to obtain in Europe, but is easily found on US eBay, you may be able to find it through a local transmission shop.... https://www.ebay.com/itm/12629846252...Bk9SR-ix_IuIZA

If you haven't done a fluid change, this would be the opportune time to install this valve kit.

 

Thanks! I'm aware of the transgo upgrade. I can get it here for around $120 and I'm considering doing so just to be safe, but I did assume that A-drum failure would cause consistent issues, not random once-every-50 drives issues.

 

You need to take into consideration when the fluid warms up and the expansion. That you also may have a cracked valve body (the 2nd video), which can cause intermittent issues... the combination of issues that can occur depending on your driving conditions (traffic and/or acceleration). This to include fluid condition, proper top off level, clogged filter or all the above. Lots of video on YT about this.

There is a site member (Mrjay622) who eventually found his top valve body cracked as he was experiencing slipping. He initially did the upgrade, but the issue persisted and had to break it back down again and ultimately found the crack.
Ok, dug around and finally found thread of the crack he found in his valve body Post #9...https://www.jaguarforums.com/forum/x...ersing-259786/

Here's another thread to review... https://www.jaguarforums.com/forum/x...pgrade-265918/

 

New filter proper ATF and fill to proper level I know some will say additive doesn't work it depends I had 150k miles q45 Infiniti the transmission had delay shift adding 1 bottle of Lucas transmission fix solved the problem till I sold it I believe it will be helpful with such high mileage

 

I think this problem is the reason he got the car dirt cheap. With the known issues with this trans, plus the miles, this is going to call for more than miracle fluid. He should at minimum drop the pan, replace the filter and upgrade that regulator valve.

 

Over time and mileage high viscosity ATF is not bad choice
Lucas is high viscosity imo it's just like engine over time you can jump from 0w30 to 10w40 after let's say 50k mile adding 1 quart to the lt71141 won't make harm with high mileage automatic transmission actually flushing high mileage automatic transmission and adding fresh fluid could lead to many problems specially slipping because it's not new and the clutches are already worn . He have long way it's not just transmission the car will probably have leaks here n there problems will show up probably soon

 

The issue is more persistent now, happening on most cold starts for a few minutes before it goes away completely. I've ordered the TransGo valve from the US and once it arrives I'll be dropping the pan and replacing it myself, of course alongside fluid and filter. Looks pretty doable. If that fixes things, I'll be happy. If it doesn't, I guess I'll drop the pan another time and inspect further.

I'm gonna order a new filter and ATF soon. While researching I see both Mobil 71141 as well as ZF Lifeguard 5 being named as the preferred ATF. I can get either here in Europe but the ZF is almost double the price of the Mobil. I'm assuming the 71141 will do fine. I'll read up on the Lucas Transmission Fix a bit, it could be worthwhile at this mileage. I also read that the bolts for the trans are both T27 or T30... What's the consensus on that? I most definitely don't want to strip any boltheads.

I got the car for cheap mostly because Jags are unpopular here for tax/gas price reasons and because it had a broken AC pump that made it sound like a rattling paint can instead of a glorious V8 The trans has been pretty flawless for the 10k kilometers I put on it. We'll see how screwed it is soon. I can't really justify a replacement or rebuild financially, so I'm hoping it's fixable on my driveway.

 

Get the mobil 1 the original fluid is made by esso both zf and mobil source from esso I'm not sure about liqui moly 1200 or other brands . For the filter get OEM or this one H2522XKIT made by MANN

 

Thanks, I got them all waiting in the basket. The car is going for MOT today and if that goes well, I'll order everything and do the trans service as soon as the TransGo valve arrives. Around €230 for everything including the TransGo. Still better than a rebuild.

 

I have the 722.6 trans, so I'm not for sure on remembering this. But, I believe the 5HP ZF24 transmission electrical connector was known to leak and had pin issues. This is where the electronics go into the trans. So, since you'll be down there, be sure to check this.

I also ran across what appears to be an original repair manual for the 5HP (pdf)...hope it helps.

 

Maybe FEBI is available in your local area?(made in Germany)
Equivalent to LifeGuard 5 and ESSO LT71141
FEBI ATF Automatic Transmission oil Fluid ATF1 for Jaguar Land Rover