4.8 Auto box

[Tunja]

Hi Guys, what could be the fault with a 4.8 auto box not changing from 4 to 5 gear other gears seem ok. Inside box or electrical control issue?

If its internal, any ideas of cost or will David S have a spare box :)

[iandvl]

I presume you have already flushed and replaced the ATF ?

[Tunja]

No, was looking at buying it but with faulty gearbox.... Hmmm need to make a decision to take a chance or not. really need a +- cost worse case scenario

[iandvl]

Sorry. Cannot comment on that.

My knowledge of the 4.8 autobox is also somewhat limited considering the ex wrote my 4.8 off before I could totally grok the auto thing.

I'd suggest calling David and getting a quote for another autobox. I'm sure he will have spare. I presume you have his number ?

[Spike]

Ernie, going on vague memory here because my brain is now full and I now only memorise what I'm currently trying to solve not what I notice in peripheral vision along the way

Shortened story....When I was fault-finding non-gearbox related stuff on my GRX I discovered somewhere in the multitude of editions of the manual that there is a fairly thorough fault finding section for the auto box and there are many solenoids n wotnot that operate the various functions. "If it goes into this gear but not into that gear then this solenoid is the problem"..."If there is a delay in down-gearing under X condition in Y gear then check such-n-such circuit" etc etc. Your problem may be very basic!

If you take the trouble to cross reference the manual editions, which can get complicated but that is another story, pretty sure you will find the info you're looking for

Is the 4th to 5th problem while driving in Auto or Tiptronic?

[Spike]

I had a scratch around and this is the first reference to the problem that I found. There are probably more instances in the various editions. Enough to give you a clue that it might be a minor electrical gremlin

[iandvl]

Reference manuals, in case you don't have them, are available from the DropBox link posted here:

https://patrol4x4.co.za/viewtopic.php?t=7667

[Tunja]

Thanks for all the advice

[JohnBoyZA]

Hi Ernest, unusual issue. Did you check the transmission fluid level? Or better yet, flush/replace ATF as Ian suggests. As Spike asked above, what about steptronic, does it still not change? Please keep us updated.