I have been trying to troubleshoot a gearbox issue I have with a 2003 4.4V8. I bought it on the assumption that the gearbox was screwed but on driving it I discovered the gearbox itself seems ok. I was getting the "trans fail safe prog" & it goes into limp mode & 4th gear mostly upon moving selector from park to drive. If I turned it off & put into neutral, then start it was ok but then sometimes wouldnt start. On occasion it would do it over & over, other times you can start the car drive 40 miles with no issue. It also does it from cold too, sometimes as soon as you engage gear. I thought it must have been the xyz inhibitor switch. I removed it, drilled out the rivets & got a chap to test it & it passes the continuity test so appears fine. If it's not that then what could it be? Test drove it & it stopped going onto trans fail safe when I went from park to drive but then does it driving Like say a min later.

Other faults I was having is randomly I would get the "trans low box neutral" can be 5 bongs after another then nothing for the rest of the journey or again for weeks. I did try low box but it just flashed & didn't go into low box.

Other fault I get an the odd occasion, I think twice now it's "trans overheat" I wondered about a blocked oil cooler.

It also sticks in 2nd gear on occasion & can only be shifted manually into third but no higher. You then turn it off & it's fine.

The guy I bought the car from said that the gearbox was leaking & cooler was blocked but no gearbox leak that I can see.

I have had it on a diagnostic at a garage & got two faults. "Trans range sensor circuit malfunction (PRNDL)-intermittent " & "output shaft sensor circuit - intermittent"

I also put it on a laptop running rsw all comms & got two faults. "Gear switch fault general fault" & "output shaft speed sensor fault general fault"

Right I then decided the other day to remove the low box motor & test it as in the powerful UK vid on YouTube. Here .

From what I could tell it was all ok & I got the motor to spin up. I took of the cover to the brush driven motor & found one of the copper bushes was cracked & broken. I removed the broken piece & the bit left seems to be in contact ok. I put it all back together & now I get trans fail safe as soon as I start it up. I can drive it though & it's not in limp mode but it can go into limp mode at any time like 5 mins or 30 mins later & then gearbox locks up.

Also now I get the "trans low box neutral" now coming on & staying on longer where before it would bong on & off. Also now it keeps bonging "high range" I have again tried the low box button & it does nothing at all now, doesn't even flash. So since taking of the low box motor & messing with it, it faults different than it did before. 2004 RR 4.4 V8 Autobiography

Last edited by PaulM on 15th Oct 2015 9:21pm. Edited 3 times in total

I'd say it's the Hi/Low motor on the transfer box, it uses canbus for most of it's operation so if it isn't getting the right feedback then it will do all sorts of funny things to the rest of the gearbox system...

I'd get that fixed and working first and take it from there.... Pete

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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I did test it as in that vid & it seemed to be ok but I'm kinda thinking the same thing. I just don't want to fork out for one to find its not that. 2004 RR 4.4 V8 Autobiography

Yeah, there not cheap even second hand, this is what Rave has to say about the transfer box ecu and errors connected with it, does this sound like yours??...



Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

The low range mountain symbol does not stay on, in fact it doesn't even come on at all even when trying to select low range. 2004 RR 4.4 V8 Autobiography

haven't a clue then, could be anything.... Ecu, motor, tranny box..... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Tried disconnecting the low box motor but made no difference. Well in fact I didn't get very far in it as if kept going into limp mode straight away. Once removed, does the low box motor need calibrating after refitting? Pretty sure I read something about it somewhere. Also can it be re-fitted incorrectly? 2004 RR 4.4 V8 Autobiography

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Is it generally the best thing to have electronics check on the computer first.

To me, this sounds like a wiring fault, or water getting into the wiring or switchgear. Have a good look around underneath, especially for chafed wires or water ingress, (The Air Con drains being a prime source....)

MW Car history includes: LR Series 3, RR Classic x 4, LR 101, Discovery 1 and 2 and now FFRR.
Yes I'm a masochist....

I did wonder that myself Mike about wiring fault, I have had a good look under there but whereabouts are the air con drains? 2004 RR 4.4 V8 Autobiography