AF20 auto box oil changed but need help

[G-cav]

Hello guys I drained the oil from the auto box and 3 litres came out I'm told the box carries 7 litres in total and 4 is left in the torque converter so it should be done twice, I just want to know after how long since the 3 litres being re-newed do I have to wait to change the oil again, the flashing S still keeps going off but only starts once the car is warmed up just after the blue bit on the temperature gauge, would anyone know why this is still going off the selector switch has been cleaned along with the contacts, I had grease in it but it was going off soon as is started my journey now it's all clean now and now only comes on when the temp needle passes the blue bit on temp gauge all help appriciated thanks

[Cavalier342]

4 liters in a torque converter? Sounds a bit much..

The haynes manual doesn't specify the total capacity but says 3.0 to 3.5 liters at fluid change. Now whether that means total or what's left in there, I don't know.
Check your fuses, there are 2 that relate to the automatic transmission itself, and one for transmission/reverse lights I believe.

My old box played up when I first had the car, cleaning the switch didn't help, but a replacement did. Hard to find but something that needs to be gotten unfortunately. Cleaning may help, what grease did you put in when you cleaned it?

[G-cav]

Thanks for reply, i thought these boxes had 7 litres I read on google and they had to be changed twice but your right when I drained old oil it was only 3 litres that popped out so would this be ok or would I need to changed it again soon to make sure the oil has mostly all has been renewed, the oil that came out was completely dark it looked like close to motor oil, the grease I used was moly grease I was told to use, but it was no good I now cleaned it completely an shined the contacts, also even if I switch the ignition off and in the s light still flashes and doesn't clear the fault hope this helps, do you know what fuse there is for auto box I seen the reverse light one and that's all fine is there another one that is to with the transmission ? Thanks again

[Cavalier342]

Right, what I would do next is perform the paper clip diagnostic test. Do a search on the forum, I can't remember where the thread is located but there was information on how to do it. Basically, the diagnostic plug in the far right corner of the engine bay, between the bulkhead and the nearside strut housing can be un-plugged, and a paper clip pushed into pins A + whatever the transmission letter is, someone may confirm which. That will flash an error code on the dash with the (s) light.

When I changed mine, the old stuff wasn't too bad but it was fine after I changed it. I only drained out what was in the box through the drain plug and re-filled it through the dip stick.

[Robsey]

Fuse for autobox is Fuse 16 - 10 amps.

Okay - diagnostics..

To get the "S" light to flash out the fault codes, short pin A to pin C on the diagnostic plug,  turn on the ignition - engine not running.

17 Solenoid 1-2/3-4 (Voltage Low)
21 Throttle Position Sensor (Voltage High)
22 Throttle Position Sensor (Voltage Low)
23 Coolant Temperature Switch (Voltage High)
25 Solenoid 1-2/3-4 (Voltage High)
26 Solenoid 2-3 (Voltage Low)
27 Connection Solenoid 2-3/Solenoid TCC
28 Solenoid 2-3 (Voltage High)
29 TCC Solenoid (Voltage Low)
31 No Engine RPM Signal
32 Pressure Regulator Solenoid (Voltage Low)
33 Pressure Regulator Solenoid (Current High)
36 TCC Solenoid (Voltage High)
38 No Transmission Input RPM Signal
39 No Transmission Output RPM Signal
41 Gear Error Hydraulic Fault (usually an internal transmission mechanical failure -  forward clutch ?)
42 Pressure Regulator Solenoid (Short Circuit)
47 Down Shift Protection
48 Battery (Voltage Low)
49 Battery (Voltage High)
56 Selector Switch (Incorrect Signal)
65 AT Oil Temperature Sensor (Voltage High)
66 AT Oil Temperature Sensor (Voltage Low/High)
67 AT Oil Temperature Sensor (Voltage High)
75 Transmission Switch (Voltage Low)
76 Engine TPS Load (Signal Incorrect)
77 Kickdown Switch (Voltage Low)
78 AT Shift Time (Too Long)

[G-cav]

Thanks guys, I will do the paperclip test, mine does seem smoother after oil change but the flashing s still there , do these auto boxes have temp sensors as it comes on once it goes over the blue bit in the temp gauge ?

[G-cav]

Sorry me again, can someone give me a short run down on how to read the codes when doing the paper clip test thanks

[Cavalier342]

Ok, have you found the diagnostic plug? Read Robsey's post, short out those two pins. A and C. Leave the plug in a safe position, and go turn on the ignition. Not the engine, just ignition. All the dash lights come on. The s light will go off immediately. After a few seconds, it will start flashing. It will go flash, *pause* flash, flash. It will repeat that twice more, so that is code 12. The pause between flashes indicates a new number. That is to say that it is running the diagnostic. If there are any fault codes recorded by the ECU, it will flash them out after the initial code 12.

Count the number of flashes and write the numbers down. Long pause - new number.

e.g. Flash Flash_pause_ Flash Flash Flash = Code 23. Each error code will flash out 3 times. Gives you a chance to remember it. Once all the error code/s have been flashed out, it will flash Code 12 again to say that's the end of the diagnostic.

Good luck.

[G-cav]

Hello guys just me again I did the paper clip test and I believe there to be 4 faults, the codes I have got are , 23, 28, 36, 41, I really can't makes out what it can be I know there is a list above about high voltage to splonoid and one of the codes is about forward gears internal, just want to know of this is a expensive job or can I DIY it and also is there a matter of time before it packs in or would it keep
Going just want to know the damage thanks again

[Robsey]

Three of those codes are for "Voltage High".
I am sure that these are basic wiring checks... that anyone with a reasonable understanding of electrics could sort out.

Possible short to battery voltage.
A matter of checking wiring for chafing or dodgey connections.

The fourth is a fluid fault.
The internal gear blurb - could it be something as simple a a fresh fluid change.

If a fluid change doesn't sort it, then it may be something expensive.
Hard to say - worth ringing any old school auto-box repairers.
Maybe they would be able dust off some old fashioned fixes and advise if it is cost effective to fix or to find a salvage auto-box.

Only problem with a salvage box, is that it could be okay or it could be worse than yours.

[Cavalier342]

Sounds like the selector switch is faulty to me. The boxes themselves shouldn't get damaged unless the fluid is never changed and you rag them all the time. Finding a replacement switch could be a mission however, breakers yards are your best bet, always ask for automatic cars, or if someone here is breaking an auto model..

[G-cav]

Thanks rob, I done the fluid change last weekend and it was really dark I re filled the box again it seems smoother but like when I done the paper clip test it showed up so It might be more deeper fault in the box runs ok I ain't run it long enough just locally and back

[G-cav]

It may be a selector switch as once I cleaned the grease out and cleaned the contacts and reinstalled it the fault has been not going way when I have switch the ignition on and off , where as before it would clear the fault this was before I cleaned the switch

[Cavalier342]

You may have fitted one of the contact pins back in incorrectly or maybe some old dirty grease is trapped in there.. If you feel comfortable taking it apart, give it another check. Worth eliminating without spending anything.

[G-cav]

Thanks andrei, I had the switch apart twice and cleaned or up with electric contact cleaner as well as abrasive paper and then contacted cleaner again making sure I got it right in the gaps also used a small needle to make sure it was all out so I'm hoping I didn't miss anything, also wanted to know worst case senario if it was to completely go or is it a slow process for the box to go

[graham8v]

If you need a new selector switch (the one under the bonnet) I've seen a new one on one of the vauxhall parts search sites online, was expensive, £170 or more if memory serves. but can be got. If you need the interior selector, there's one doing the rounds on the bay often for £25 plus post, has been on there several times, so you should find it easily enough

HTH

[planetc]

The only one I ever had with a solenoid fault (one of your codes) was repaired with a replacement solenoid inside the gearbox.

[G-cav]

Thanks guys, PLANETC is it a easy job doing the solenoid inside the box or a job for specialist also how much am I looking at if it was the gear box solenoid and also is there a reason why they may pack up thanks in advance

[Cavalier342]

Anything can pack up at any time, there's no way of saying why, but if the boxes are kept maintained and not too abused, they shouldn't fail for the life of a car. My old AF20 was bullet-proof even after accidentally jamming in Reverse while moving forward (faulty selector switch causing me to shift manually), it just seemed indestructible.

Though if you don't take it for a long run every now and then, it won't help. The fluid needs to be hot for the box to function at it's best.

[G-cav]

Thanks andrei, the fluid was changed but still no difference, pulling away when the sport light is not flashing it doesn't want to move so have to select 1 to pull off and shift up manually, I have took it on a long run 1 hour but soon as it gets a little hot like over the blue bit on the temp the sports light starts flashing and even if I shut the ignition off and let it reset when I start it and drive off it starts to flash again, so really confused what it may be as it should clear the fault at least

[graham8v]

have you had a look at your radiator to make sure it's not blocked or got bent fins? I'm sure the auto cars had a different rad that incoroprates a gearbox cooling section. I'm wondering if the box is overheating causing the flashing s?

[Cavalier342]

Not really, the automatic models have almost the same radiator, but with another pipe coming out of the nearside of it which feeds coolant to the transmission. Overheating wouldn't be an issue unless you were trying to tow a truck with it on a hot day.

On a side note, have you checked the breather hose to make sure it's not blocked? The problem you describe points to the selector switch anyway but worth checking. The breather hose comes off the top of the box, just under the battery tray and it is routed towards the bulkhead and ends under the flap section of the scuttle panel, where the long rubber seal is.