Transmission trouble 75k miles after refurb. 5HP24

[TriX5]

So, it has been over a decade and the E53 has done 75k miles since my torque converter grenaded and made a refurb of the trans necessary. It was working perfectly since then with two drain and fills done.

About two weeks ago it went in to fail safe mode. It reverses fine and seems to have drive in failsafe but none in 1st/2nd (?) There was plenty of fluid in it, I recovered what came out when I had a look in the pan. The pan has some fuzz on the magnets but nothing out of the ordinary. When I restart the engine it feels like it wants to move but then reverts to failsafe within the first half second.

I am planning in my head how to get the trans out in order to have a look at the internals. Could be an O-ring, an axial needle bearing or some other mechanical problem I guess.

My question is, could this be a problem in the valve body and if so, what am I looking for? The fact that it wants move before going in to failsafe makes me think there is pressure from the VB in first gear and I would be inclined to assume the VB is ok but any insights would be helpful. (Here's hoping RRPhil pitches in as well :-)

It would of course be less work to just pull off the VB but I have sort of resigned myself to the need to pull the trans. Since the E53 is not critical to our needs I can take my time. However, I don't want it blocking my garage while figuring out what's wrong, it would help to have some idea.....

[RRPhil]

Is there any way you can determine whether the forward gear that the transmission is failing safe into is 4th or 5th? This is significant because it tells us if the A-clutch is responsible. The default is 4th gear, but it will failsafe into 5th if the A-clutch is the problem.

When it comes to determining which gear is selected, nominally the driveline is geared at 29.3 mph/1000rpm in 5th and 23.5 mph/1000rpm in 4th but, because the torque converter is open in failsafe mode, it can be tricky getting the driveline balanced so it’s neither driving nor in overrun when taking the engine speed reading at a steady road speed on the level.

Phil

[TriX5]

Thank you so much! To see if S-mode made any difference I tried it and noticed the gear indicator jumps to 5th when it switches to failsafe. Assuming that indication is correct, I'd be looking at the A-clutch then? I am not driving it at all so as not to over-stress the remaining function, but I could try it and verify with the rev counter and speedometer which gear it goes into.

My car is a June '03 build. IIRC, the '03s did not have the cracked A-clutch cage problem. My car saw quite a bit of city traffic up to 100k but more longer distances after that and has not been used for traffic light drag races. So, likely, it is a smaller failed component. (BTW, now at a shade under 170k miles.)

This weekend I am clearing my garage as I just completed a garden shed. The house construction stuff is moving into the shed. My winter tires are moving there as well some of the nine bicycles.......ugh, got to sell some bikes. I'll report back when I have it apart.

[RRPhil]

Yes, your transmission will have the stiffened A-clutch drum as it was manufactured after November 2000, and also the main pressure valve with the 10mm wide land. That’s not to say that these strengthened drums never fail at the snap ring groove, but it is much rarer.









The cause is more likely to be ‘the usual’ axial bearing wear, and subsequent O-ring failure, I would guess.









Phil

[TriX5]

Thanks! Great info, I will print and have it handy when I open it up.

[TriX5]

So, this has been long coming as I have been sidetracked into a couple of house projects in prep for some visitors from overseas. Then a problem with a hand required minor surgery and slowed me down for about a month in all.

I decided to pull the engine/trans and sub-frame as I did last time. Since I don't have a lift and I don't want to fight a heave item lying under the car, this seems a better way. I also want to do a few things on the motor that I should have done the last time it was out as well as fix a few oil leaks..... It is almost like a British motor cycle, if it doesn't leak, it is because there is no oil in it :-) It doesn't drip on the driveway but weeps enough for the pan to be wet. I should have done the reassembly of the engine a bit more focused on sealing things last time it was out. I omitted sealant here and there where the sealing surface meet on odd junctions, which came back to haunt me.

During the last week I finally got back to it, removed the front end and took off all the electrical and fluid connections top side as well as the steering shaft. I took off the stiffening plate and broke free the sub-frame bolts. Next is getting the exhaust off and the drive shaft. Then disconnect the anti-sway bar, hang the calipers from the coil-springs and disconnect electrical in the wheel wells. Finally the two bolts holding the knuckles to the front shock absorbers and that should free the whole thing. Hope to have it out over the weekend, then crack the trans open next week.

Stay tuned :-)

[Factory6speed]

M539 restorations has a nice video of rebuilding the valve body on the e70 x5.


Some trans install tips I got from a semi truck mechanic I wish I had before: use a digital angle gauge to get the angle the pilot is at and set the input shaft to the same on the jack. Thread two small studs in the bottom holes slotted for a screw driver. Get those to catch the bell housing holes and it should slide right up.

[TriX5]

Yesterday pulled the drive-train out of the E53. The cart I had assembled from some 2x4s previously had long since become part of a soffit in the garage :-) The setup I concocted this time did not work as well but eventually found a way to drop the front of the engine just below the frame rails and it could be pulled forward. I split the rear bracket and the transfer-case from the transmission and pulled the trans off the engine, then called it a day.

Today I had an hour to spare before dinner and I popped off the bell-housing and the intermediate plate. The thrust bearings look to be in rude health, same as they looked last time daylight touched the internals. However, the two o-rings on the input shaft are toast, both split and did not feel very elastic.

I will probably find some more o-ring trouble in the A-clutch. This morning I spoke with Matt at Eriksson Industries and they have the thrust bearing that goes behind the A-clutch in stock. Just need to figure out what else is bad if any and what to replace while in there.

[X5chemist]

Nice work! If I pulled mine like that, it would be out for months. I would go and replace just about all the plastic stuff possible. Plus, preventative maintenance.


Kudos on taking on transmission work. I just pay a shop to work on mine I can pull and install transmissions all day.

[TriX5]

Spent a little quality time with the repair manual to remind myself of how the 5HP24 is put together. Last time I had it open was 2010 I believe.

As soon as I pulled the B clutch assembly out I realized that the clutch pack in the A cage was at an odd angle! Sure enough, my A cage is split. Now hunting for the replacement part.

This morning I thought about handing it to a trans shop but it would take more time to find a qualified shop than to dig into it. And even if I located a shop then the uncertainty of the quality of the fix would be overwhelming. The DMV area is not know for great automotive service enterprises.