Transmission issues summary

[SlickGT1]

Yea I am waiting for a new gasket and filter from ECS, along with another $400 worth of parts. Going to drop the pan and filter right away. I found a case of 12 of ZF lifeguard fluid online for around $200. Not bad I think. Ordering that today as well.

[740ilDuke]

Nice! Went with the hi-roller fluid too! I looked at it and decided that the Valvoline MaxLife had always given me great results and would be better than what they had developed a decade ago when mine was filled up.

I hope this solves your issues!

[SlickGT1]

Yea I wouldn't mind getting some cheaper fluid, but I just can't seem to find a comparable one to the ZF Lifeguard. Well it might be because I am an ATF noob.

[bigfish]

hey all,

I have an 03 e53 4.6is. I'm running the Dinan S3 kit wich includes Vortech V-2 supercharger running 9.5lbs of boost, I have 175K miles on the it. I also added an M3 steering wheel with paddle shifters from Mr. Paddle Shift.

This car is my daily driver and it puts a smile on my face everytime I start it up. However, I have been having an ongoing issue with rough downshifts between first and second gear. I often drive this car in sport mode with manual shifts. My service engine soon light is on most of the time. The code is failure of the tourqe convertter to lock up. My local shop is suggesting a new (rebuilt) tranny and also replaceing the tourqe converter at the same time. They are not able to issoloate the issue.

I would like suggestions on where to go from here...

Thanks,

TB

[RRPhil]

The torque converter lock-up clutch in your 5HP24 is designed to spend the majority of its time constantly slipping unless you’re cruising at steady speed on the highway. To maintain a constant slip rate (around 2-3%) the LUC piston is fed a hydraulic pressure which is proportional to engine torque. If your engine is tuned (the transmission was originally designed for a maximum of 440Nm input torque) then clearly the PWM duty cycle on the proportional solenoid that supplies this pressure (shown in photo below) will be that much higher and the LUC will have to work that much harder to maintain constant slip. You could maybe try swapping the torque converter lock-up clutch solenoid with one of its three identical neighbours (labelled A, B & C below) to see if the DTC changed at all ?



but at that mileage it probably would be sensible to replace the converter anyway. Was anything done to uprate the transmission when the engine kit was fitted (increased pressures, etc.)?

2-1 downshifts on the 5HP24 should be seamless as the engaging element is a mechanical sprag and not a clutch.

Phil

[Helmuth]

As written here: http://www.xoutpost.com/bmw-sav-foru...on-broken.html

I had that "rrrrrrrrrrrrrrrr" at exactly 1400 and 1900 rpm when accelerating in D mode. Had that now since about 3 months and it was getting worse.
Dealer did a test drive and the first reaction was: new transmission. I told them that this is not an option since I believe only the lock up clutch might be the culprit.
They changed the transmission oil now (at least half of it - they said they cannot change the oil which is in the TC ....?!?)
I was also told that the error "gear monitoring 4+5" (?? Gangüberwachung 4 and 5) had been stored and after a 60 km test drive with the new oil it did not come up again. Now the rattling is much better but it has not disappeared.

Not really sure what to do now because a tranny change would be about €3.500.- (material only).

On different webpages I could read that changing oil more often might help here but ........ ?

Helmuth

[fmugur]

I just updated main post with firmware update fixes. The EGS firmware update fixed the hard downshift from 2-1. So if you have a hard downshift from 2-1 make sure you update the EGS module before you do any further investigations. It might be an explanation but at this point I cannot explain why with the old oil the tranny was working fine and with the new one I needed to update the firmware. I guess the new firmware can handle the tranny better when some parts are worn out inside there.

[jbond007]

Here is the part from my post on my 4.8is tranny fluid flush that pertains to this thread

PART 2! The Lurch!

After a week my car started shifting down from 2-1 with a lurch or a feeling like I was getting rear ended whenever I came to a stop. Very harsh. Upshifts were harsh too.

My 2 cents is that the transmission didn't "know" it had new fluid and was operating on settings it "learned" or adapted to.

Took to my mechanic who reset the "Adaptations" in the transmission and then updated the software to the latest for the ZF. It was the best $180 I've spent! It shifts better now than before I even did the fluid change! Do these two things first if you have issues after flushing your fluid or with the "lurch" or harsh shifting in general.

Happy motoring! Hope this was helpful.

[bbultman]

Phil[/QUOTE],
You seem to be knowledgable of the 5hp24 trans. My '03 4.6is has a throttle oscillation at constant speed under 62 mph. It feels like the torque converter locking/unlocking/locking/unlocking every 2 seconds or so. This only happens under light constant throttle between 1200 and 2100 rpm. When in cruise, no oscillation. When in Sport mode, no oscillation. 2-1 downshift in Sport mode is a little harsh, but seemless in regular D. No other symptoms, no codes. Dinan trans software installed.

Does this sound like a LUC solenoid issue? If the TC can be commanded to lock up when in cruise or Sport mode, seems like the TC is working normally and more like a valvebody solenoid issue. Any comments appreciated. 141k miles with no history.

[RRPhil]

I’ve already posted this over on a Range Rover forum but, as an identical torque converter is used in the 4.4l E53, I thought it may also be of interest to a few of you on here.

I’ve now disassembled my old (108k mile) 5HP24 torque converter so that the lock-up clutch, which was giving me vibration problems, can be examined. The vibration issue disappeared when the converter was replaced with a re-manufactured unit.



Impeller vanes are radially straight in the F38 ZF 5HP24 torque converter



Torque converter stator element which houses a one-way clutch so that the stator is held stationary during the torque multiplication phase but can then freewheel once the coupling point is reached and the fluid flow direction changes



Torque converter turbine



Engine-side of turbine showing castellated slots which engage on lock-up clutch friction plate



Following removal of turbine, lock-up clutch assembly is exposed



Clutch piston is friction welded into impeller casing and part of its hub has to be machined away to release piston. Friction welding process has to be accurate to apply correct preload from six tangential springs to clamp LUC in ‘on’ position (i.e. transmission has to feed hydraulic pressure to engine side of piston to hold the converter ‘open’)



Lock-up clutch piston after removal



Lock-up clutch friction plate in impeller casing



Though I was expecting to find the friction plate completely worn it had 0.72mm (0.028”) of material left on each side (but unfortunately I don’t know what the thickness of a new plate is nor ZF’s wear limit) and looked in fine condition





The only indication that there’d been any problem with the clutch were chatter marks on metal friction face of the piston



Opposing metal track on impeller casing looked smooth & free from damage


So, although not immediately obvious from its condition, this lock-up clutch was causing vibration issues in my Range Rover at low engine speeds (the cattle grid noise) which were cured once it was replaced with a re-manufactured unit. My only theories at the moment are that :

a) the friction plate had worn sufficiently for the preload applied by the tangential spring straps to reduce enough to cause a stick-slip effect during the converter’s ‘continuous slip’ operating phase (typically only around 3% relative speed)

b) the friction plate started out with grooves in the friction material to allow fluid to flow across the surface when it was engaged and these had worn away causing the friction faces to overheat (or at least change the friction coefficient).


ZF vs GM

Okay, so maybe the friction material in the ZF 5HP24 torque converter LUC wears eventually to the point at which it causes a vibration due to lack of clamp force – a sort of early warning system. Judging by the amount of material still left on the plate though, replacement isn’t urgent and the transmission will soldier on for a good while without causing further damage.

On the other hand, the GM 5L40-E transmission in the 3.0l wears through its LUC friction material (due to low system pressures) without any warning at all - it’s fitted with a torsional vibration damper - and the first you know about it is when it dumps huge quantities of metallic debris into the fluid causing the whole transmission to grind to a halt, by which time it's too late.



I think I prefer the ZF system!

Phil