Now before anyone asks if I checked the solenoid and switch wiring, yes. I get a audible click at the solenoid. I've pulled, cleaned and swapped out solenoids with others around the shop, bench tested. Took off the OD sump and cleaned the filters.

Prior to it not working it would engage harshly/erratic. Now it does nothing. I'm not super familiar w/ how the OD unit works, but I was thinking of trying some trans tune in the tranny.

 

A) I thought seafoam was a gasoline treatment for cleaning injectors

B) what year/model vehicle, with which transmission are we talking about here?

 

Do we assume you checked the OD relay?

 

assuming you're talking about the external OD on a M46/M47 stickshift car...

these overdrives are really underdrives, when the "OD" is off, the OD unit acts as a planetary reduction gear... when you switch the OD 'on', it locks it so its 1:1... it uses a clutch band much like an automatic transmission. find a old british car mechanic and he'll know how to rebuild it, volvo used the same OD units that triumphs and MGs used in the 1970s.

 

There's seafoam for engines and trans tune for transmissions.

Yes, I am talking about the m46 with p or j type laycock OD units. I have a turbo so it's the more beefer one, I forget which is which.

I'm sure I can find a used unit or rebuild it myself on my free time or have it done, but I really don't want to a bunch more money into my turd that needs a engine overhaul (it's going through to much oil).

It's good for hauling so I keep it around. It would nice to get 27-28 mpg instead of 20 or less.

 

An audible and felt click at the solenoid w/ the light turning on the dash eliminates all electrical.

 

My 240 would also 'click" but didn't work. I removed the solenoid and put a bent metal coat hanger into the hole. It would not go in!! I pushed it and wiggled it and viola it wet all the way down. I replaced the solenoid and it still works perfectly. I also removed the solenoid and replaced it with a "plate" eliminating the solenoid altogether

 

michael, we're not talking about a AW7x automatic OD here. this is a manual transmission with a seperate OD unit on the output. if the OD solenoid was bypassed like that, you would either always be in OD (making 1st, 2nd too tall) oryou'd never be in OD, leaving you with no 5th for the freeway.

 

I'm new at this. Sorry! I found this thread trying to find an answer to my problem with my 240 odo. Might you have my answer?

 

I'm new at this. Sorry! I found this thread trying to find an answer to my problem with my 240 odo. Maybe you have my answer

 

no problem, I just wanted to put that out there so anyone /else/ stumbling on this thread wouldn't get confused. the 4 speed manual with external OD was a 70s thing, they phased that out in the early 80s in favor of 5 speed manuals, so they are pretty rare today.

to 'guest01', I may have the OD service greenbook in my collection somewhere, I can't copy them (they are copy protected document files), or even screen print from them (really copy protected) but at least I could summarize the procedures for rebuilds. I glanced at a parts breakdown of the J units, phew, complicated beasties.

 

I opened my instrument cluster of my 1990 240. Found the broken gear and replaced put all back together only the odo will not work. When I found the gear the motor housing separated from the small circuit board. Did I break the motor?

 

you really should start a new thread, this has nothing to do with guest01's M46 overdrive issue.

 

I can't! !

 

go here, Volvo 240, 740 & 940 - Volvo Forums - Volvo Enthusiasts Forum and click 'New Thread'.

 

Actually the M46 was used into the '90's, as ALL Turboed Red Blocks needed its stronger characteristics to work... The M47, a "true" 5 speed, started to show up in NA 240/740s in 1987 but it's not strong enough for turboed cars. The M46 Laycock De Normanville (I love the name) is an ancient beast but it works quite well and is still quite common...

BTW, I doubt that the Sea Foam for trannies will work...

 

It's very possible that passage way on my 740 is clogged, didn't think to check that when I had my solenoid out.

 

I was going to say my 740 is a 88. I've never heard a 5 speed not being powerful enough. I have more service tech. info on volvo's, but as an enthusiast I know honda's. People turbo all 5 speed tranny's. DX, CX, STD. People choose to go away from the auto, but that still has been done. I don't see why the m47 wouldn't be strong enough. these 740 turbo's don't make that much power. (well auto's suck, but the 5 speed is ok).

as far as the seafoam, It's clearly clogged or not making pressure. I suspect it wasn't used very often when I got it, it had 147k the wires to the switch where cut, and I bought it from a guy in the city with already went through a clutch.