Manual to Automatic

[volvobm]

I would like to covert a 740 2.3 to auto. I prefer to drive auto. I have a donor auto car . Is there any issues with doing this convertion ?

[SignumGB]

Originally Posted by volvobm

I would like to covert a 740 2.3 to auto. I prefer to drive auto. I have a donor auto car . Is there any issues with doing this convertion ?

Being non-mechanical (more electrical), is it more hassle than it's worth? Or is it simply a case of swapping manual out, removing clutch pedal and ancils and bolting auto box on? Is there any timing/calibration that needs to be done? How is the lubricant system affected? Electrical contacts if any?, indication lamps on dash if that model comes with it.

[john.wigley]

I'm inclined to agree with 'SignumGB', 'volvobm'.

I too prefer automatics, but if I were in your place - unless you have another reason why you want to keep your present car - I think that I would look for a good automatic replacement and sell the manual vehicle. The donor vehicle could remain as a valuable source of spares if you have the space to keep it.

From memory, the manual and automatic radiators are quite different - the auto incorporates an ATF cooler, which can also cause problems if it fails internally and results in cross-contamination of the coolant and ATF.

You would also need to check the rear axle ratio, as this varies by model and year (Haynes), and I think the auto box is longer than the manual, meaning that you would need to swap prop shafts as well.

I'm sure that there will be other considerations of which others more knowledgeable than I am aware, but it does sound to me like a big job for relatively little gain.

Regards, John.

[Laird Scooby]

Originally Posted by volvobm

I would like to covert a 740 2.3 to auto. I prefer to drive auto. I have a donor auto car . Is there any issues with doing this convertion ?

Go for it! I'd replace the engine and box as a unit, might have to raise the rear of the car quite high to remove and refit as a complete unit but worth the extra work to raise it as it saves so much time stripping the box and driveplate off the donor engine then refitting to the manual engine, no spigot bearing to worry about (removing it) and so on.

I'd keep the manual radiator and buy yourself an external ATF cooler (i had to do this when i couldn't source an auto radiator for love, money or bribery but could get hold of a manual radiator easily) as it will cool the ATF more efficiently and elimintae the possibility of getting coolant into the auto box.

If memory serves, you'll need the propshaft, obvious things like the gear selector quadrant, pedal box, clutch mech blanking plate, auto gearbox rear mounts and i can't think of anything else just now but sure there are more things.

While the auto box is out of the car, renew the extension housing seal and bushing, it's a fairly easy job and worth doing. Also inspect and perhaps replace as a matter of course, the propshaft centre bearing.

As for pitfalls, is the box you've got in the donor car just a normal 4-speed auto or is it electronically controled? Have a look at the plate on the side of the box to confirm which it is. If it's electronic control you'll have to transfer the wiring, ECU etc and if it's an AW-70/71 with the overdrive lock-out button on the gear lever, you'll have to swap the wiring for that too.
If it's the ZF 4HP22, you won't have that problem.

One last thing, is the engine the same spec as what you've already got? You may find you have to swap the ignition control modules (under tha dash above the pedals usually) as they are very often programmed with different advance curves to suit the auto box better.

Thinking about it, you may also need to swap the centre console over to gain the correct shift indicator and so on.

Long time since i've done an auto to manual (i know you're doing the opposite but almost everything is the same, just in reverse) but quite happy to help with advice.

One last thing, instead of Dexron II-D, i'd suggest Carlube ATF-U and once you've drivien about 1000 miles on it, do a part-change/sump-dump as there's a very high chance the box has been sat a while and may not have had a fluid change for a long time before you fitted it to your car.
Keep an eye on the fluid, if it gets dirty quickly, do another cump-dump after another 1000 miles or so thenagain if it's still dirty after the next 1000 miles.
After that, one sump-dump a year should keep it running very sweetly.

Don't be tempted to use the flushing method of changing the fluid, the new fluid is thicker and pressures are likely to be higher instantly and the seal-swell (a nickname for the compound added to the ATF to revive/condition the seals) won't have had time to work its magic. Doing sump-dumps gives it a chance to do that while cleaning the box internally.

[volvobm]

My idea is to have more power in my 740 estate. The other option is to put a more powerful engine in the automatic car. As from the answers there is as much work in changing the gearbox. Option 1 is a 3litre from 960 still Volvo.
Option 2 is a Rover V8. I have a very good V8 in my range Rover classic.
Anyone put a V8 into a 740?

[Laird Scooby]

Originally Posted by volvobm

My idea is to have more power in my 740 estate. The other option is to put a more powerful engine in the automatic car. As from the answers there is as much work in changing the gearbox. Option 1 is a 3litre from 960 still Volvo.
Option 2 is a Rover V8. I have a very good V8 in my range Rover classic.
Anyone put a V8 into a 740?

Yes, been done many times apparently. Not necessarily in England but a popular choice these days is the 1UZ 4.0 V8 from the early Lexus LS400 as the gearbox bolots straight in seeing as it's a renamed AW71 as used in the Volvo to start with.

Economy wise it's probably the best of the V8 conversions because it employs a lot of modern techniques in building the engine and if you get the loom as well there's no reason it should be hard to do.

This video is actually about dropping a 1UZ into a 245 but the idea will be the same in the 740 but if you search YouTube, there are all sorts of V8 conversions including a 5.0 supercharged Mustang V8.

https://youtu.be/hDmtezlc98o

There are plenty to choose from on YT so fill your boots!

Unless the engine in your Range-Rover has been changed for an SD1 or P6 unit or is a 3.9 EFi, chances are it only pushes out about 125bhp so probably less than your 740 if it's a B230E (131bhp) at the moment.

[classicswede]

I have done the swap both ways many times.

As long as you have all the donor parts it is all easy enough

[aardvarkash10]

let me see if I understand this - you are proposing to spend around 80 hours and an unknown sum of money faffing about to do a conversion (which, oddly, is normally done the other way around) when you can go and buy pretty much the vehicle you propose and sell the vehicle you have for little or no effort.

Are you barking, or do you just enjoy the challenge?

[Laird Scooby]

Originally Posted by aardvarkash10

Are you barking, or do you just enjoy the challenge?

His location says Dublin Ash, not Essex :

https://www.google.co.uk/maps/place/...563!4d0.075766

People can be called "a bit Dagenham" which means they're one stop short of Barking!

[volvobm]

Are you barking, or do you just enjoy the challenge?[/QUOTE]

When you live on an island with no Volvo 740s available your could be driven to being called barking!

I have been looking for a 740 automatic turbo estate in silver . I'll travel to get one and pay the right money. Just can't find one