Troubleshooting Transmission Issues - 2002 4.4
 

Hey there, I could use an expert opinion to see if I'm on the right track for troubleshooting the automatic transmission issues on my 2002 4.4.

It has 183k with unknown transmission service history. I traded an E46 wagon for it 2 weeks ago.

-Shifts normal in 'D' until it's warmed up.
-Has never given an error code.
-Issues go away (or more likely just masked) when in 'S' or manual. Haven't tested this on long drives though.
-When warm, it'll shudder between 2nd and 3rd, particularly under light throttle and going uphill.
-When warm, it'll hunt in 5th gear. It acts like slipping, but doesn't seem to be affected by throttle.
-When hot, after driving for a very long time, it'll hard downshift into 1st.

My thought process so far...
-It's temperature related, and issues get worse the longer (hotter) it's run.
-I *think* being that the issues are in multiple gears, I could rule out anything related to a single gear.
-The temperature sensor is easily diagnosed (https://xoutpost.com/986442-post13.html)
-If the temperature sensor checks out OK, what is the proper temperature for this trans to run at, and how do I read it while driving?
-Following the last bullet, if I find it's running too hot, are the trans cooler and thermostat the only culprits?

Let me know if you think I'm on the right track, and any assistance you can lend on the questions above. What I don't intend to do is throw parts/time/money at it without proper diagnosis.

Thanks!

Not going to find that "Expert Opinion" on this board. Don't know of any members on this board that rebuild ZF trans for a living. There are people who have rebuilt their ZF trans on this board and posted their experience.

If you looking for an "Expert Opinion" you should look at "Gary Ferraro's" Youtube channel. Gary has placed on his youtube everything you wanted to know about disassembly and rebuilding the ZF trans in X5, Jaguar, and Rover.

You have a hydraulic pressure issue that is related to the ATF temperature. The clutch packs that engage the gears are not able to maintain pressure because of the hydraulic pressure issue that is why you have the shudder and the slipping. The hard shift from 2 to 1 is because of the pressure valve in the valve body. The pressure valve is a known problem with this trans.

Two weeks after acquiring the X is why the previous owner was willing to trade this X for your E46. He already knew about this problem and was just looking to dump the X.

The only part that will fix this problem is a new or rebuilt trans. You can always listen to the Cliff Clavens on this forum and try a fluid change, or a new harness with a new temp sensor, or a new or rebuilt valve body or some new solenoids, but in the end, all those suggestions are just WAG (Wild Ass Guess).

Flame on I got my fireproof suit on today.

Read the comments in this video.

https://www.youtube.com/watch?v=DsQqpkC8Xs4

Do the symptoms posted by Ryan Toth sound familiar?

With your group of problems, I'd be inclined to agree on needing a trans (new/rebuilt). Will definitely be the quickest in times of turnaround. If it was just one problem with the trans you might be able to do a parts repair on yours. Or you could pick up a used trans for $500ish and roll the dice that it doesn't have the same problems your current one does.

Upallnight likes to insult the other members on the board for wanting to try to repair things by starting with cheaper fixes (even if they don't solve the issue)... but I've always thought all parts fail eventually (and these X5's are at least 12 years old now), and I have no problem using the shotgun approach if it means I can prevent a future part failure/downtime even if it doesn't fix my current problem. He gives out very good advice and knowledge, but you'll have to learn to disregard the "extraneous" material.

If you call calling out the Cliff Clavens on this forum insulting than I'm guilty of that. But if you read the OP comment he wanted not to throw parts at the problem. I gave him a source of info from a Guy that owns a Transmission shop and have posted videos on the ZF5HP24 trans that is in the OP's X. I gave him my opinion on why his trans was slipping. I just caution him since he is a newbie nob about the Cliff Clavens on this forum.

I appreciate the responses, but I'm looking for more troubleshooting experience.

If the issue is temperature related, why wouldn't you diagnose that specific issue? You could very well shell out a lot of money to rebuild a trans only to find out a failed trans cooler thermostat causes the rebuilt trans to have the same overheating problems.

You have a seal within that isn't holding pressure. As the trans warms up the fluid becomes thinner allowing it to push by the seal and lose hydraulic pressure. We see it a lot at the dealership as we have two techs that know the 5hp24 very well and have rebuilt a few.

You can use a program like inpa to monitor the trans fluid temp as you are driving.

Image courtesy of Overboost.

https://xoutpost.com/attachments/x5-...ssion-temp.jpg

For the past 3 Z6HP26 transmissions that I had worked with its all been the valve body solenoids. I have replaced them also the gasket that connects the valve body to the transmission and of course the transmission fluid and filter. Then do an adaptation
and go for a good long drive so that the ME learns the values again and it should run better. That is, the past three not saying that you fix all of this transmission like what I just explained.

Good luck.

I had the same thoughts with troubleshooting the transmission in the '03 I bought last month. I was disappointed to find a lack of tried and true methodology in testing for faults in these transmissions. I was told a lack of pressure testing ports was the reason for this.. So a lot of work done on these seems to be by using the Force or something. In my case I just gave my X to an experienced shop for a rebuild. I will pick it up tomorrow. I hope I like the way it drives and all...my experience with these vehicles so far has been limited to driving up behind several tow trucks, which has been the only way it's been able to get from one place to another:P