1986 240 5-speed into 1980 240, what needs to change?

Man, how fast things change... I was just looking to pick up a 1995 944 to pull some parts off of it for my 1992 944T. Instead, that fell through just as a 1986 245 5-speed showed up!

So, I'm been wanting to change the transmission in my 1980 242. The 3 speed BW saps energy, makes highway driving 'buzzy', etc. (I'm sure you all know already). So, I was thinkg about putting a AW71 (pulled from my old / wrecked 1992 940T). When I asked about it, it became clear that the speedo was going to be an issue. Certainly one that could be overcome, but still just another thing to work around. So, now that this rusty, no title, 5-speed 245 showed up locally I'm wondering what obstacles I will have to navigate in order to install the manual transmission?

Perhaps now would be a good time to ask about what stock Volvo manual transmission is a good candidate for me? I don't know which transmision would be in a 1986 240? I can't remember all the nomenclature, but is a M46 better than a M47?

TLDR: Is a 1986 240 5-speed a good donor car for a 1980 240? What will be easy, what will need to be modified / overcome? Which transmission is a good solid unit?

Yes but you'll still have a speedo issue unless you swap the back cover on the OD.

Redwood Chair said:

Yes but you'll still have a speedo issue unless you swap the back cover on the OD.

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Can I take that to mean that if I put a new back cover on the overdrive, I can connect a speedo cable to the manual transmission?

I'm assuming that Redwood Chairs response means that the later transmissions just got a cover plate to replace where the speedometer connected. And, that if you put on an older cover, I would still be able to connect the speedo cable that is in the 1980 242. Do I have that right?

Nope, your car has a mechanical speedometer, just switching the cover plate won't help you. You would also need to switch in a carrier in the rear end with the 12 tooth ring and also change your speedometer to electronic. I just use a GPS for a speedometer.

deadken said:

Can I take that to mean that if I put a new back cover on the overdrive, I can connect a speedo cable to the manual transmission?

I'm assuming that Redwood Chairs response means that the later transmissions just got a cover plate to replace where the speedometer connected. And, that if you put on an older cover, I would still be able to connect the speedo cable that is in the 1980 242. Do I have that right?

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Yes plus the worm gear shaft from an earlier Laycock De Normanvillan OD, and the drive gear plus the mounting bits and bobs for said drive gear.

In the correct color for your rear end ratio.



So basically an early parts OD and several hours of fussy recombining by someone who knows the ins and outs of the Laycock ODs.

Or of course a known good early [pre 86] OD and 'simply' swap that on there.

NB:

Also your 80 B21F probably has a 1.75" driveshaft and the 86 has a 2" prop so you might want to grab that too.

Whoops sorry bad information from me, I saw back cover and immediately thought of differential not transmission. My humblest apologies.

During the transition years from cable to electronic speedo there could just be a plug in the speedo hole of the OD. Then it's just be a matter of sourcing the speedo gear with it's housing and retaining hardware.

1986 240 should have a M46. We typically call this "4 speed with OD", not a "5 speed". I think there is some confusion in this thread because of the nomenclature.

M46 will have a mechanical speedo drive. All M47 cars have electronic driven speedos with a sensor on the rear axle.

I prefer M47s for simplicity and weight (easier to put back in!) but the M46 might have the edge on durability. It's not uncommon for M47s with high miles to wear out the countershaft bearings. That said, I have one that is merely a little noisy in neutral with about 300-350k on it (it's been in a few cars).

It might work to swap the '86 rear axle in to get your speedo to be accurate. That is, assuming that Volvos all have the same "internal speedo ratio" in the cluster itself.

tjanson said:

All M47 cars have electronic driven speedos with a sensor on the rear axle.

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That's what I thought until I saw a parts catalog that shows a speedo gear for M47.

hiperfauto said:

During the transition years from cable to electronic speedo there could just be a plug in the speedo hole of the OD. Then it's just be a matter of sourcing the speedo gear with it's housing and retaining hardware.

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Rare bird for sure.

The three 1986 240 M46's I've dealt with were all without any provisions for the gear.

tjanson said:

1986 240 should have a M46. We typically call this "4 speed with OD", not a "5 speed". I think there is some confusion in this thread because of the nomenclature.

M46 will have a mechanical speedo drive.

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Read what I wrote in a couple places above, in fact the 700 cars always had electronic speedos so they didn't get the mechanical drive parts.

tjanson said:

All M47 cars have electronic driven speedos with a sensor on the rear axle.

I prefer M47s for simplicity and weight (easier to put back in!) but the M46 might have the edge on durability. It's not uncommon for M47s with high miles to wear out the countershaft bearings. That said, I have one that is merely a little noisy in neutral with about 300-350k on it (it's been in a few cars).

It might work to swap the '86 rear axle in to get your speedo to be accurate. That is, assuming that Volvos all have the same "internal speedo ratio" in the cluster itself.

Click to expand...

Early cars had various combinations of gearing setups to mechanically drive the speedometer.

Ok... FWIW: I've owned at least 5 1800's. All of them were manual transmissions. I've dealt with Laycock '5' speeds, but I've never had to mess with the actual overdrive short of checking fluids and some solenoid wiring. And, to be entirely clear, it was mostly all a very long time ago. I did a clutch on my '72 ES in my garage and put the transmission back in by myself but I was likely in my late 30's or early 40's at the time and likely before I had hernia surgery. Yeah.. I didn't love the weight of that Laycock transmission...

So, I guess, the next logical question would be: How unreasonable would it be to swap in the later instrument cluster, or at a minimum, install the later speedometer head into my cluster?

I know that I'd have to swap in the later rear end (which I might just have a G80 installed before doing). Considering I was going to swap over the driveshaft, as suggested above, I'm wondering how much more to pull the wiring out of the donor car and 'upgrade' to the later style speedometer (basically taking everything from the flywheel back from the donor car).

I don't suppose Dave Barton does a mash up speedo cluster? (I'm checking his webpage(s) now..)

Not so sure I'd rip the main body harness all apart like that.

Maybe just install the electronic speedometer and surgically wire it in.

I think I saw a write up on that conversion job on here once, but I don't recall the author or the details.

Redwood Chair said:

Early cars had various combinations of gearing setups to mechanically drive the speedometer.

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Isn't that what the little number at the bottom of the early speedo is for? I always thought it related to rear end ratio of the car.

Redwood Chair said:

Rare bird for sure.

Read what I wrote in a couple places above, in fact the 700 cars always had electronic speedos so they didn't get the mechanical drive parts.

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What is a "700 car"?

Another option for OP is to spring for a GT cluster, but replace the speedo with a programmable one running off whatever - a swapped abs strut, sensor, and tone ring, rear axle sensor, or some sort of custom setup on the driveshaft or transmission output flange. VDO makes programmable speedos that are non-offensive.

tjanson said:

What is a "700 car"?

Another option for OP is to spring for a GT cluster, but replace the speedo with a programmable one running off whatever - a swapped abs strut, sensor, and tone ring, rear axle sensor, or some sort of custom setup on the driveshaft or transmission output flange. VDO makes programmable speedos that are non-offensive.

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Or make one...It is just a plate with round holes in it for motorsport gauges. Its the guages that make a real gt cluster valuable, If you already are doing a speedo swap, might as well build your own. VDO vision series look proper.

a 700 car is a chinese paperclip/bbq/screwdriver pre-cursor......

I did this swap into my 79 245. Used everything from the engine back on the 86, then wired the speedometer from the 86 into the 79 and mounted it in the 79 instrument panel. That took some work, but three are posts to follow for all of this. I have them saved on my PC but am out of town. Search deep enough and you will find them.