I have a 1999 XJ8 VDP with 120K+ miles. I see a lot of discussion about
the ZF transmissions taking a dirtnap during that range of mileage.
But, is it a concern only for a certain range of serial number XJ8's ?
Mine is VIN: SAJKX6043XC860673. Is it in danger of a big fail soon?

I am considering changing the Trans Fluid and filter. A local trans shop
(Not a big brand transmission shop) guy has toldme that if the fluid and filter
was not changed at the 50K range then any replacement after that will
certainly cause a failure? True, partially true or downright not true?

Regards and P O R (Press On Regardless)

Bob

 

Well, I changed my fluid and filter at around 90K miles, and then did another fluid change about 10K later - this is because you can't get all the fluid out without pumping it out through the cooler lines. But anyway, my tranny is still fine at ~140K miles. I do baby it a little when changing gears and I keep it in sport mode. BTW, I used Pentosin fluid. I think other folks have also.

 

Bob, I don't trust your transmission shop. The recommended procedure is now to change the fluid and filter at 50 or 60K mi, I forget which.

Your early model is more likely to fail, I think, and it would be wise to change the main pressure valve while the filter is out. It only takes about 1 hr. extra. Link below.

http://jagrepair.com/images/AutoRepa...%20ZF5HP24.pdf

 

I am not a fan of transmission FLUSHES of any kind, these can create issues when dislodging particles. Regular drain and fills are good routine maintenance though. My experience with transmissions (I've rebuilt a few...), is that a drain and fill is to be regular maintenance on a good functioning transmission. It generally is not good policy to change fluid to try to address an issue (unless there is a revised fluid among other things).

If your transmission is working well and you're trying to change to extend life, change away!

 

+1 to changing the main pressure valve. The revised and updated valve is less prone to sticking...which will limit the chance of a high-pressure fluid pulse that overstresses the input (A) clutch basket on take off (which is when the torque is the greatest and you have the most chance of shattering the basket.

Ericcson, who rebuilt my tranny, explained it that way to me when they were doing the overhaul.

If it's not broke, nothing to be lost with a filter and fluid change (not power flush...just drain and refill)...and if you have the bottom off anyway, replacing that valve may give you many more miles.

 

I've had two X308s a 2001 with 165K, 2000 w/ 125K on the clock & have experienced zero tranny issues. I drove the 01 hard & only got rid of it due to an accident. In fact of all the former business partners/associates that had/have this era of XJ8s I can only recall one having transmission problems mind you he was was the type to change the oil once the check engine light appeared lol.

 

I think the latter are more common with these cars when they were new... It's only when they get to us, 16 or 17 years down the road, that are concerned about keeping them in good nick that issues or how they were supposed to be treated when they were new are now being dealt with.

Let's face it, when these things were current production, the number of people with grey hair who bought them to run to the shops or bingo hall vastly outweighed those with less highlights on the scalp who bought them for the heritage and style...kick the tires and light the fires kind of drivers.

I remember buying a '90 Caddy Sedan de Ville (I was only 46 at the time...) and the looks I got going down the road: "hey, what's that young guy doing in an old Phart machine?" were more common than not. Didn't help when my dad went out and bought one for my mom...

FWIW, I know a couple of Beemer and Audi folk who have the same box in their rides who have experienced the A basket issue...so, it's not isolated to the leaper marque. Also had an '85 GTI which supposedly was prone to machine a hole in the case because VW didn't design a snap ring groove to locate a shaft...I never had a problem, but know first hand of a couple of my friends who did. So, it's up to fate, I think.

But, changing the fluid, new filter, and updating the valve can't hurt, right? And may be cheap insurance, no?

 

I've had three cars with variants of the ZF 5HP24. 2 Audi A4s with the ZF 5HP24A (one gone, one for sale) and a BMW 740i with the 5HP24. I am not a fan of them whatsoever. I've had decent luck with the 6HP26A in my A8, but it seems thats the only thing I've had luck with on that car!

I think 30-60k mile changes might get you decent longevity. I would definitely do what bdboyle mentioned preventatively, but I'd keep it in mind that it likely won't last like a 722.6. My 97 A4 which had 229k on it when the transmission failed. I thought it was a record, nope, based on what I found, it was the second unit lol.

 

The ZF's transmission problem is not fluid related.

That's not to say that fluid changes -- properly done are a bad idea. It's the "properly" done part that's important.

While I can understand (sort of) the idea of a "sealed" box back in the late 90's -- the fluid was not widely available in the aftermarket and most cars were dead buy 120k. I don't like not having dipsticks and drain plugs -- they make maintenance easy.

Both boxes hate heat -- they die quick.