Does a gearbox oil change ever work?
 

Hi
Had the “transmission service required” light on the other day- we topped up the transmission fluid & re set the light & all seemed fine, TIL today, just came back on.
So, I had an oil change planned for it anyway but my question is, does it ever cure anything or am I just better off getting another box from a guaranteed scrappy & replacing it! (I think the whine I have is from 3rd/4th gear too)

It does need an oil change so maybe it’s throwing a fault up from the crappy oil?

Clearly it depends on the true root cause of the problem - but yes it can and often does work.... I'd say about 50% of the time.

However... usually it's problems like harsh or lazy shifting and flaring. It's less often anyone getting an error message on the dash has it cured by new oil.

Have you had the codes read? The TCM does log errors but sometimes they can be very non-specific.

For £50-£100 of fluid, personally I think it's worth a try.

The 5 speed boxes can be quite hard to find in guaranteed, used condition. Remember you need one from a AWD car (not 2WD).

If you have the later 6 speed box they are a bit easier to come by, but again you need a AWD donor.

full oil change and software upgrade is the first path to follow … after the fault codes are interpreted of course..

I did get the codes read, it was on my mates Delphi diagnostic equipment so it wasn’t as good as the vida, but I’ll not moan as he’s saved me a load of cash so far!
I think the next step is a full oil change then take it to the Indy near where I work & get them to diagnose the remaining two faults I can’t seem to clear.

1. Anti skid deactivated
2. Transmission service required

I’ll have to stop being cheap & pay the £35 plus vat for a plug in!

The anti-skid is often something really simple like a wheel sensor or ring.

Does the car drive okay (gearbox wise) ?

I have checked all the reluctor rings carefully- sort of gave up now!
As for the way it drives, its ok but the whine annoys me at 30-40 mph & I’ve noticed in traffic when I put it into “P” then into “D” I have to wait to feel the clutch engage (if it has a clutch?) before I pull away or it bangs loudly!

That it just the sort of fault that fresh fluid (& software & adaptations reset) sometimes significantly improves.

I’m going to do a drain & dump tomorrow & I’ll do another over Xmas I’m going to use the carlube atf u gear, does anyone have a pic of the drain plug? I’ve read there is another plug that can be mistaken for a drain?

suggest you do a search for gearbox oil changing on the forum and follow either of the two methods mentioned. ie Gibbons method or dump and top up. The drain plug only drains oil in box and there is another load of oil in the cooler. The drain plug has an inner & outer . Inner is the plug on bottom of level checking tube. Only take this out when the engine is running to check that you have correct oil level in box. Taking this out with engine not running means you end up with less oil than you should do and you end up loosing drive as you go round corners!!

What autobox do you have?

Measure what comes out from your sump and replace the exact amount.