The return of my overdrive...a few observations

I received plenty of helpful advice (and a look at the Workshop Manual - thanks Peter) after my post 'A newbie writes' set out the sad story of the disappearance of o/d from my 740 GL Auto. Happily, it is now fixed. A few things I learned along the way:

1) If you go to a Volvo main dealer and ask for a relay, they won't ask why you think you need it, they'll just sell you one. It now seems that if the button on the side of the gearstick turns the 'orange arrow' dash warning light on and off, the relay is OK. It would have been nice if the parts guys had said 'but is the orange arrow working ?' and saved me £40 when I said 'yes'.

2) An autobox service, full power flush and filter replacement will come in at about £100 from an autobox specialist, at least in S.London. 'It uses £40 worth of ATF alone, mate.' I gather some practitioners use a detergent flushing medium rather than all new ATF and suspect these are best avoided.

3) If your autobox is old but working, a No 2 will almost certainly make it work better (it's part of the 30k service, I believe), but autobox experts to whom I spoke said it was unlikely to cure the 'no overdrive' problem if it's the solenoid at fault (although if the problem is just general gunkiness clogging the solenoid it might).

4) It's definitely worth checking the wiring (or in my case, having it checked by someone who knows what they're doing) with a test lamp before embarking on No 5.

5) If it's not the switch, the relay or the wiring, it's almost certainly the solenoid, and it will need replacing. A Volvo solenoid will set you back between £180 and £210 plus VAT, not counting club discount (I heard various figures) but Braydon do new ones for £75 plus VAT. For, er, 'pre-owned' I was quoted £30 by breakers in Rochester and £60 by another in London, but you take a chance on how long they last. If you can't even face this, the no-cost option is to machine a small slot in the face of the duff solenoid and refit it, which lets the fluid pass at all times. You get the o/d back but you can't turn it off. (As an aside, one autobox specialist told me that the solenoid from a Vauxhall Carlton (at least, I think it was a Carlton...) is the same, and I discovered the AW70 was also used in at least one Isuzu and several medium-sized Toyotas in the 80s, so thay might be sources of cheaper bits.)

6) If you can't face replacing the solenoid yourself (it's two bolts and a wire, but quite fiddly) it should be no more than 15-20 mins work for a pro who knows what they're doing.


7) Braydons mail-order service is excellent, though when fitted to the car it turned out that the first solenoid they supplied didn't work properly (I don't blame Braydon, obviously - they couldn't have known) but they supplied a replacement no quibble after I rang to tell them what had happened. I may have been helped here by the fact that I was having the solenoid fitted by Charlwood Restorations (very helpful), so there were no awkward questions regarding the competence of the fitting.

8) Solenoid No.2 fitted by Charlwood in 15 mins, problem cured. At b****y last.

Phil D

I obviously had a bit of finger trouble when sending this message and as the one up there is the one with the relpies this is the one to get rid of.....

Phil D