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Just bought a 1997 XK8 and I am running through all of the things it needs done before getting it smogged and registered.
I have been going through all of the forum threads i can find and seeing that everyone else has experienced every possible thing i am running into and implementing most of your solutions to my problems ( thank you all ). Especially the "stuck" parking brake that the previous owner had just been driving through, car has a lot more power at low speeds now hahaha.
I think the last large outstanding thing that I am facing down is the previous owner reported that the transmission would slip after about a half hour of driving. I haven't experienced the transmission slipping in drive yet, however i had it rev the engine up while being put into reverse for a couple seconds before it felt like the reverse gear softly engaged and the car started rolling backwards.
I have seen that other forum members have detailed that these ZF transmissions have a bad part in the valve body that destroys the forward drum, i unfortunately don't know exactly how to diagnose what is going on with the transmission without tearing it out of the car. Can anyone give me any advice on that front?
I may have lied, one more thing just popped into my mind that i am somewhat concerned about. The dash voltmeter is reading 13v while the car is idling, i replaced the battery with a new unit and while that fixed my battery problems, that did not fix my voltage problems. Bad alt or voltage regulator i am guessing?
Last edited by Mad Hatter; Jul 29, 2019 at 08:19 PM.
Reason: Noticed my bio isn't showing the car information :( Added year to description of the car
Friend, What do you think is wrong with the voltage? The guage is an inaccurate borderline idiot guage that's generally directionally accurate. You need a simple voltmeter to check voltage .
Many small transmission symptoms are 1st addressed by charging the fluid. This may be a long shot in your case. Let's see what folks with more tranny experience say.
Oh yeah, very important, always post the year and model (it's an XK8, not an R right?).
John
Hey, yeah, that is odd. I added the car to my forum bio but it isn't showing for some reason.
It is a 97 XK8 Coupe.
I had already realized that the dash gauges were idiot lights, but I had read somewhere on these forums that the voltmeter gauge was accurate.
I will go throw a voltmeter on the battery terminals with the car running to see exactly what the alternator is putting out at that point.
The previous owner supplied a filter change kit for the transmission. I was about to go change the filter and what oil I could get out, just wanted someone with better transmission skills than I have to chime in and tell me what I should be looking for in the condition of the oil, what kind of level of metal particulates is acceptable, what to do and expect really. I have rebuilt an engine, and replaced as far in as the pump on a transmission, but i am much less knowledgeable than most of the users here on this beast i imagine.
EDIT: Put the voltmeter on the battery terminals and had 14.2v at idle. I am more than happy with this, would like to have some words with the people who decided dummy gauges were a good idea. Wrong information is more dangerous than no information at all.
Last edited by Mad Hatter; Jul 29, 2019 at 10:21 PM.
Reason: Providing more diagnostic information
You are fortunate, it sounds as though your electrical system is humming along. The 12 volt battery in good condition should have a charge of close to 13 volts. Jaguar running should charge at about 13.5 to 13.7 volts.
The transmission sounds as though it might be a good time for a fluid change. It sounds like it may be low. When you do the fluid change make sure to follow the steps in the tech manual for drain, fill and level check. Overfilled is just as bad as under filled.
If you need a copy of the tech manual send me a private message with your email and I will send a link to a copy in my dropbox.
The pan on the transmission is leaking, who knows how long the PO let that leak go. I bet you are right that the fluid level is low, regardless of any other things that may or may not be wrong with it.
Your bio shows a 1974 XJ6 and new 1997 XK8 which means you understand how "picky" our cars are. Some good advice on the voltage problems from Johnken and avern1. I would check grounds and possible battery drains too.
Your description points to a previous owner saying your transmission had rough downshifts when hot. Plus you say there is a delayed engagement for reverse. Bad ATF and low fluid levels are the first "easy" fixes. I've attached the Jag Technical Bulletin on this issue, but it's a bit simple and not really directed at the home DIY-er.
Johnken is right in that changing out the fluid and filter is the first thing to do as it may fix your gremlins and is a perfectly DIY-able job. Better with a lift (if you can get access to one) rather than doing it while flat on your back. Drained fluid should be clear and red/cherry colour. If it's brown and or black, with metal on the pan magnets, then it's bad news. Acceptable levels of metal shaving, is hard to quantify. Fine particles on a finger tip I would describe as fine, but any small metal chunks not acceptable. On my 1999 XK8, I had dark brown fluid with both magnets having a thin coating of fine metal sludge. I suppose you could put it through a filter to be sure, but I didn't.
Don't forget you've got to run the car and later go back and drain/fill again as the old fluid will be held in the Torque converter. My car took approx. 6.5L initially and a total of 7.5L second time round. Don't know why the difference in my case but my gear box is running fine now and fixed by downshift problems.
One worry for the ZF5HP24 is that the valve body is the Pressure Relief (PR) bore which tends to wear and a lack of fit with the PR valve causes pressure spikes which can damage the A Drum. This is a known weakness of this particular gearbox, but there are ZF and Transgo replacement upgraded PR valves which are inexpensive, but a frightening experience to install. Taking apart an automatic valve body is not for the faint hearted. I've worked on a manual transmission before, but this Jag was the first auto gearbox where I looked inside a valve body. Here's a link to the Transgo PR valve I put into my car. TransGo ZF 5HP-24: 5HP-24-PR
Pic below of the front lower half of the valvebody, where end plate has to come off to install new Valve body - beware the springs.
While you're in there, I would check out the condition of the valve body, as there are internal channels for the ATF flow, and the F channel is next to the edge and is also known to crack through. The valve body can be replaced but, if you're in this position, then I would actually start seriously looking at the ZF5HP24 entire service/upgrade kits available on the market. This gearbox is very common across brands so kits/parts are available including an upgraded A drum (another known weakness).
I am going to fix this car come hell or high water is what I am going to do
This XK8 is going to be my daily driver while i am building the other jag out to be my mona lisa.
The XJ6 that I have never gives me any major problems to be honest with you, but it also was lumped before i bought it, and then i cut the entire wiring harness out of it and made a whole new one. It doesn't have much opportunity to be british.
Thank you for all of the tech manual information in those links. I had been scouring the jag forums for this kind of information and was finding great anecdotal information that i will cherish, but these manuals are a dream come true if actually do end up having to crack this thing open.
Right now the plan is to make space in the garage, drain the fluid and change the filter out since I just have one sitting here. Will refill the transmission and then take it in for an inspection at a local transmission shop that i trust, assuming that it doesn't look like a grenade exploded in the bottom of the oil pan.
Ultimately, I want to learn how to rebuild transmissions, the XJ6 needs to be converted over to a 700r4 from a TH350 anyways. I might just go grab a 700r4 core from the junkyard and a rebuild kit and start building some knowledge. If i feel confident after that, maybe I will try to make myself a spare 5HP24.
I think I have already fallen in love with the XK8 to be honest with you. Unfortunately it seems as though every single time I hop in the car I find another brittle piece of plastic broken. I guess I will be getting good at gluing a car back together.
Draining and refilling the ATF in these ZF transmissions is much easier and more precise if two people are involved - one person underneath the vehicle pumping the new fluid in once the pan is at the proper temperature, and the other person in the drivers seat running through the gearshift patterns as required during the fill process. And loosen your ATF fill plug slightly BEFORE you remove your ATF drain plug. You always want to be sure that you can indeed remove your fill plug because if you cannot, you will be dead in the water if you drain your ATF first....
OEM life time fluid was lifeGaurd 5, Pentosin manfacters LifeGaurd 5 for ZF. Pentosin ATF-1 is LifeGaurd 5. Last mechanic put in Bilstein I drove on it for maybe 5 miles, then researched it. Bilstein does meet the LS spec, but is a synthetic Blend.Pentosin ATF-1 (LifeGaurd 5 ) is 100% synthetic. I had the bilstien removed and flushed pronto and after putting the Pentosin ATF-1 back in there was a very noticeable difference in the smoothness and shifting of my 2003 XJ8. I had been using the Pentosin ever since I had the tranny rebuilt. My tranny died due to ignoring the ABS Not Available warning light. The light come on because the ABS computer units have bad solder connections inside which all eventually fail. When the unit fails it no longer tells the tranny valve body how fast the car is going. So the valve body doesn't open and close all the different valves that control the fluid inside of it, so the tranny burns up. The next sign other than dropping the transmission pan and inspecting the fluid and the pan will be the car going into restricted performance mode. After a while it will go into restricted performance more and more often until the tranny just dies and leaves you stranded.
Jon89: Good call, I likely would not have thought to ensure I could get the filler plug open before draining fluid. Where there is a will there is a way, it will come open somehow, but good logic to put your ducks in the correct order.
GreggP: The check engine light was on when I got the car, it was throwing a code that when translated to jag was "abs ecu failure". I quickly checked the wiring and found a broken ground wire on the front right sensor. I am still waiting on getting an OBDII scan device that can clear the codes so that I know whether the problem is resolved or not.
I have been reading the refill procedures and thinking I may be a little thick. It appears as though the instructions require use of a jag portable computer (PDU)? How else would i get the transmission temperature or read and clear transmission codes. Is this things that other OBDII scanners are capable of? Or am I just going to be under there with a IR heat gun haha?
Mad Hatter, a good visual resource for drain, replace filter & fill on the ZF is a video by old time forum member Reverend Sam; although his XK8 (as is mine) is a 2003 model with the 6HP26 trans, it is very instructive and led to my successful fluid change back a number of years ago. Here's a link to the video:
With your ambitions, and savy know how, this ATF fluid and filter change should be relatively straightforward esp. if you're thinking of disassembly and re-assembly of a complete ZF5HP24 gearbox. Having never done that, but as part of my research I found plenty of YouTube Videos showing the ZF5HP24 transmission drums and clutches, but it's the internals of the valve bodies that would worry me. There are numerous small parts, such as sprung coils, within the valve body channels and also dampers, filters.
A few things I noted during my go at this.
1. Corroded T27 pan bolts are a real pain to remove on the ZF5HP24. Impact wrench is a must. Make sure you have a spare tool bit as it's easy to strip one. Have spare bolts to hand too (or in my case I just replaced the entire lot)
2. Dripping ATF is a real pain making taking pictures, to record positions, difficult. I ended up putting my note paper in plastic sleeves
3. I went with gasket sealant as well as a new gasket but don't overdo the sealant on the lip as you don't want old bits being sucked into the valve body.
4. If you're going with the upgraded PR Valve, when you remove the front lower valve body, go gentle as there's a steel dowel that holds the upper and lower together. Wiggle mm by mm and don't be tempted to stick a screwdriver in for leverage. You don't want to crack the valve body case.
5. When you re-assemble make sure the sliding selecting lever is located on the pin (otherwise the gearstick won't move). Pic below. I checked twice during my work, and still screwed it up.
6. The temp. of the transmission is available over OBD2 (FWIW I think the car needs to be in gear to read a true value), but an IR reader is fine for the job. Second time round I just used my hand on the pan, as it's just hot to touch, not scolding.
7. I used a lift at my local mechanic's shop, when he had a slow day at the garage. He had one of these tools made up for this job, for easier access to the filler bolt. Access is a bugger especially between the hot exhaust pipe and the side of the pan. A lot of forum members had burnt skin from this location.
There's a dip stick kit available to install a dip stick on the ZF5HP24 where the modification has a tube in the engine bay where you can pump ATF in. Maybe that's some thing you can think about if you're on the job. Check out this thread by Tomlite https://www.jaguarforums.com/forum/x...ailable-53939/
I had the car on a lift to inspect it before purchasing it and it didn't appear as though the fill location was difficult to get to. I have pulled engine and transmission from my 74 several times in the garage and am not too shy about getting under this XK8 to change tranny fluid.
I have a bottle and hose specifically for side fill jobs like this ( like the rear end in the 74 ). I think it will suit me quite well in this instance. I am sure I will still find a way to burn myself regardless of how safe i will be
Right now I am going to get the pan and filter off and just inspect the fluid. I am hoping that after changing the fluid I will have enough confidence in it to drive it to the shop to get it smogged and registered.
I am pretty motivated to rebuild a transmission soon, the only things that I haven't taken apart and completely rebuilt at this point is a transmission and a rear end.
Not sure if you've disconnected the battery and the DTC you have. There's an old thread (link below) showing the Drive cycles needed to clear the monitors before going to SMOG. See Post #2 https://www.jaguarforums.com/forum/x...g-test-185262/
The battery was toast when I got it, I haven't driven it more than a mile since i bought it. I definitely am going to be driving it around like an idiot for a while trying to get the drive cycles done so I can get it smogged.
I forsee getting pulled over with guns pointed in my face ( AGAIN ) at 3 am on the highway. Yay America.
Last car that I bought I got pulled over at gunpoint for not having license plates while I was driving it from the purchase point to the DMV to get it registered.
Then a week later got pulled over at gunpoint with proper registration because it matched the description of a stolen vehicle. :/
I see a very cheap rebuilt transmission in my local area for $700. The only problem is that it is listed as a 98-02 compatible transmission. It is a #1058000026 serial number transmission which according to this other post recently should be compatible with my 97 also?
Since that thread devolved into people misunderstanding the initial question, i wanted to ask it again here to get confirmation before I snag this transmission for a spare.
Transmission Slipping
