Gearbox Oddities

[ulfilias]

Hi Guys,

Never had an issue with my old 2000 FL S8 and the gearbox up to 235K. Just picked up the new one 98 PF S8 and it drove from London fine. Up to Leeds and Back and then Monday on the 12 miles to work I hit the A1 and it reved up high and no power. PNRD4321 on the dash and then power came back but it didn't seem to change gear.

Got to work an put on vagcom 17117 - Gear 3 Incorrect Ratio P0733

Cleared this off and things worked ok.

Driving home and PRND4321 came up just after starting

Cleared the fault again and I could select select things on the dash and vagcom, but the gearbox didn't seem to do much. Tiptronic showed 5 not 1. I could go back and forwards, though pick-up was slow until moving forwards. Seemed like the car can go 0-??? in one gear!

Drove to the supermarket. Parked up. Did stuff. Got back in and no error. Drove home fine.

Yesterday morning it was fine for the first few miles and then again high rev. PRND4321 and similar problems. Clear the code and this time it seems Tiptronic shows 4. The revs are a bit higher at motorway speed, though take off is still very slow until moving.

Vagcom showed
17114 - Incorrect Gear Ratio P0730
17145 - Shift Solenoid 3 (N90) : Open or Short to Ground P0761

Again I cleared them off. Left it a while. But now i get PRND4321 with a bit of a thump when i select D or R

and 17145 keeps returning.

Any ideas where or what Shift Solenoid 3 is ???
BTW I do still have the old S8 at the moment for parts etc!

Lee

[steamship]

Originally Posted by ulfilias

PNRD4321 on the dash and then power came back but it didn't seem to change gear.

Lee

If you mean that all gears light up on the dash, I would suggest the F125 switch might be the culprit (although the scan isn't throwing that error). Not familiar enough with the other codes, but others will be.

[ulfilias]

I've heard of the F125 switch. In playing with what was doing what I believe that the lights and certainly the mirror was acting as though reverse was selected.

And yeah all the gears on the dash as a bar or [PRND432]

[ulfilias]

Hi There,

Been doing a bit of net research into this gearbox, solenoids and stuff and gonna put down a bit of a link dumping ground, so A I don't loose them and B it may be useful to someone else doing research into this box

ZF 5HP24A - It seems to also be used in quite a few cars, as such rebuild / diagnostic info on the same box on a BMW / Landy etc is still pertinent and useful while not always being 100% correct, but....

The gearbox assembly seems to consist of two parts. The actual mechanical gears and the Valve body which is the brain / controller. The valve body sits on the bottom of the gearbox and is accessible through the gearbox oil pan with the gearbox still in situ.




Diagnostic PDF - & overview on how things work
http://virtusplatform.com/sam/BMW/e3...P24%20diag.pdf

ZF Valve body maintenance "overhaul"
http://www.bimmerboard.com/forums/posts/527361

Gearbox Rebuilds

BMW
http://forums.bimmerforums.com/forum...e-Walk-through

Audi S8!!!
http://www.motorgeek.com/viewtopic.p...46685&start=25

Landrover based but lots of info/specs
http://forum.landrovernet.com/showth...5HP24-teardown
And he rebuilds for a hoby
http://www.rangerovers.net/forum/6-r...d.html#p298057



Solenoid positions / Names
http://i260.photobucket.com/albums/i...t2008/EDS4.jpg

Solenoid position / Names (official) - Also links to images of parts
http://www.tsgparts.net/index.php?p=...location_5hp24

Solenoid Positions / Diagnostic info
http://www.rangerovers.net/forum/6-r...l-problem.html

Solenoid wiring harness
http://bimmerboard.com/forums/posts/1091413

Solenoid Replacement / Swapping
http://www.rangerovers.net/forum/6-r...tml#post246833


Testing a solenoid
http://www.xoutpost.com/bmw-sav-foru...rror-code.html



Removing the valve body - Youtube video on bench
http://www.youtube.com/watch?v=rJw7RWGl0Qw

Removing the valve body instructions with pics
http://www.rangerovers.net/forum/6-r...tml#post247261


Overhauling the valve body & differences between UPDATED valves
http://www.xoutpost.com/bmw-sav-foru...-question.html


ZF rebuild manual details
http://www.audiforums.com/forum/audi...al-pdf-153014/
http://forums.audiworld.com/showthre...1759363&page=5


----

After having a think and a read and having a spare car, while the fault may be with soilnoid three, debris in the vavle body locking it out or similar. I am tempted to do a full valve body swap as it looks fairly simple.

Lee

[RRPhil]

Sounds like you may have an open circuit on solenoid 3 (i.e. it’s disconnected). Solenoid 3’s only function in life is to pressurise the opposite face of the reverse gear valve (RG-V) spool - thereby preventing engagement of the C & F clutches - in the event of the gear lever being moved into reverse while the vehicle is travelling forward at speed. Consequently it may never actually be required throughout the whole lifetime of the vehicle (unless the driver has a habit of doing this!)



However, it is also activated in Neutral, which is presumably why it is being flagged by your controller.

The easiest way to test it (without having to take the sump off) is to check the resistance at the 16-pin connector.



If you measure between pins 4 & 16 you should get a reading of between 26 and 30 Ohms.

I have loads of (used) spares if you need one.

Phil

[ulfilias]

Hi Phil,

Given your name, you appear to be the gent up in Lancashire that rebuilds these for a hobby. I recognise you from one of the Landy forums and i've read numerous of your posts. Very glad to have you here. Doubly so given my current niggles.

I actually have 2 S8's one FL and one PF both with the same gearbox (fbg vs ecx but both 5HP's). The facelift one has a dead engine due to timing and throwing pistons into valves (sigh) so I got the second which has developed this gearbox fault.

We did an oil flush and it was not too bad, though the magnets had silver particles.

I was looking at Swapping the valve bodies, but testing sounds good.

However I'm a little confused.....The Code is

17145 - Shift Solenoid 3 (N90) : Open or Short to Ground P0761
Also known as P0761 - Shift Solenoid C

I was thinking from http://i260.photobucket.com/albums/i...t2008/EDS4.jpg

That C was EDS5 ???

However you circle MV3 in red on one drawing and say SV3 on your pin out???

Lee