Well, I ended up turning around halfway to work because it was still not wanting to up shift like it should. It shifted fine when cold (after idling for 15 minutes or so) then as soon as I got up to about 55 it would stay in 3rd. I slowed down it down shifted to 2nd, I made my turn and got back up to speed and it refused to up shift to 3rd again. This all happened within a 2 mile distance from my house. I drove back home, checked the fluid to see a normal fluid level on the hot line while the car was running.

Just to clarify as well the car would up shift to 2nd at 30 before when the problem was occurring and into 3rd at 60. Now it doesn't up shift to 2nd until about 35 mph or 4500 rpm and won't shift to 3rd until about 70 mph similar rpm. The old fluid did smell a little burnt but nothing out of the normal.

Again any further suggestions are greatly appreciated!

Drew

 

Hi Drew,

I'm sorry your gearbox is misbehaving even worse than before. A couple of questions: First, did you do only one drain of fluid via the drain plug, and one refill via the dipstick tube? Or did you do multiple drains & refills and drop the pan and change the filter? If you've done only one drain/refill, your gearbox may be suffering from an unhappy interaction between the old fluid and the new, in which case you need to do probably two more changes to remove as much of the old fluid as possible from the torque converter (it holds around 5 quarts if I recall correctly).

Second, did you "bleed" the transmission while the engine was running by depressing the brake pedal, then moving the gearshift to each gear position for several seconds to allow the gearbox to fully engage in each forward and reverse gear?

Don

 

Thanks for the reply Don,

I just recieved the 3 gallons today and have only had enough time to do one drain and fill. I did run throught the forward and reverse gears in my driveway while stopped and also moving before I headed out for work. There was no slipping or clunking or anything out of the ordinary at that time. I do have the filter kit and plan to drop the pan and replace it on the 3rd drain and fill.

I have seen a few things about the valve body solenoids being plugged up with gunk after sitting for a while on old fluid. Would it be worth looking into while I have the pan down? or even possibly replacing them entirely?

I guess I'm a little frustrated already just because of the current issues I'm having with my other car. I didn't expect an immeadiate difference, but I surely didn't think it would get worse.

Drew

 

One or more plugged or lazy solenoid valves could certainly cause shifting issues.



I wouldn't have expected things to get worse, either, but I have read a lot of reports online from guys who had bad fluid interactions when doing only a partial change, so it would be worth doing at least one more to see if the performance changes.

It would be interesting to hear from any members of this forum who have had similar problems or have had work done on the valve body. A friend of mine at the Jag-Lovers XJ40 forum just replaced the valve body in his car, which corrected some rough shifting. He found an affordably priced NOS valve body on eBay.

Don

 

It almost seems like the kick down is sticking so it's thinking it's trying to accelerate harder then I really am.

This is one of the reasons I like a good manual trans, it's either in gear or its not. It does what you tell it to and that's that haha.

There is a good reputable transmission shop near me and another European shop that has come HIGHLY recommend by another member on here, I may just call them up to see if they have seen this issue as well. Otherwise I may even take it into them and have it fixed right and done for good. I will need this car to perform reliably for the next few months. I appreciate all the insight you have given me Don, as well as the rest of you that have chimed in on this thread. The Jaguar family has treated me well!

In the mean time I will do another drop and fill of the trans. More updates to come tomorrow.

Drew

 

Well, still no luck with better upshifting. Looks like I will be taking it in to All-tranz, to have them repair it next week. Labor rate is only $85/hour compared to Fields $125/hour. I called Fields today and asked a few questions about it and they told me they don't really have any tooling for a vehicle this old, and they would have to charge me full diagnostic time plus what they have into it for repair. No thanks.

The unfortunate part is I really don't have the time to deeply dig into this issue. I will update next week to let you know the diagnosis!

Drew

 

It's certainly possible that you have an electrical problem, since the gearbox is electronically controlled.

The XJ40 online eBook at the Jag-Lovers forum has an excellent diagnostic procedure for testing the electrical circuits of the ZF 4HP24, but it sounds like you don't have time to get into that yourself at the moment. Please keep us informed.

Cheers,

Don