240: M46 Reverse & Overdrive Issues

[VolvoScout]

Two issues with my 240 '82 M46 Transmission have recently arisen.

A couple of months ago, my Overdrive became unreliable.
It engages about 50% of the time, with no discernible pattern to predict when.
The relay clicks and the light displays on the dash. (I replaced the relay with same results)
Sometimes it engages, sometimes it doesn't and sometimes it does a "half-engage" of sorts.

I changed my transmission fluid a couple of months prior to these issues (type F) any connection?

And this week, my reverse gear started slipping.
No matter how much I depress the throttle, the car barely moves backwards but the RPMs increase.

Thoughts?

[Mr. V]

Use a test light to verify that you get power to the solenoid when the button is pushed; if there is power verify that the solenoid works when activated (feel it, should detect it operating when the button is pushed). If the solenoid works then the problem is internal, likely worn O-rings on the two overdrive pistons.

Then again, there may be an intermittent issue with the solenoid so that it doesn't always work when it should, but I've never seen that before in my limited experience: seems to me they either work or they don't.

As for the reverse issue, do you also have slipping when moving forward, or only with reverse?

Hopefully a clutch adjustment will help, otherwise it is something more problematical, like a worn out clutch.

[VolvoScout]

I'll have to check the solenoid for power.

I don't have any slipping in any of the forward gears, only in reverse.

Tips on clutch adjustment?

[esmth]

Slipping in reverse could mean the overdrive is stuck engaged. The solenoid actuator may be stuck. don't use reverse like this, you are destroying the clutch in the tranny!

Try pulling the solenoid, the seals may be preventing it from retracting.

[VolvoScout]

After inspection and if it's determined that a new solenoid is needed, is this the correct part number? "Type J, 1232101"

[hiperfauto]

Yes that's the correct part number but it's also sold under the old part number 380771.

https://www.skandix.de/en/spare-part...typ-j/1001129/

https://www.cvi-automotive.se/en/art...repro?q=380771

http://212.247.61.152/US/main.aspx?p...e&artno=380771

[tintintin]

Duane Hoberg told me one way to quickly tell if the solenoid is usually good or not is to shake it in your hand; if it's good its internals will rattle freely.

[VolvoScout]

How do i remove the solenoid for inspection?
All I see is 1 screw towards the front, which I removed, but it doesn't seem to permit the removal of the solenoid.

[carver]

Originally Posted by VolvoScout

How do i remove the solenoid for inspection?
All I see is 1 screw towards the front, which I removed, but it doesn't seem to permit the removal of the solenoid.

You need a 1" thin service wrench. If you look at where it's attached you'll see where it goes. Important to note that you want to clean the entire area completely before you start tearing into it. These units don't like dirt etc. Here's a good reference site for more info on the M46.

[planetman]

Here's 1 on ebay.


https://www.ebay.com/itm/VINTAGE-Bon...0AAOSw31Jfg7~W

[VolvoScout]

I removed, cleaned, confirmed working and replaced my overdrive solenoid.
Reverse gear is still acting-up, and only seems to properly engage around 1,000rpm.

At idle, in reverse with the clutch fully out, it sounds as if something is spinning inside the transmission but the drive shaft does not spin and the engine does not stall

[carver]

I think the wet clutch is toast, probably sheared itself off of its connection to the shaft. You can pop open the inspection cover and check the filters for debris but it's going to need to be pulled no matter what. Full rebuild time.

Just a question, when you engage the overdrive do you clutch it or not? I talked with a Laycock engineer years ago and he said the unit was designed to be used as any other gear -- clutch in -- engage -- clutch out.

[VolvoScout]

Is the "wet clutch" the same as the "one way clutch" in the OD?
So it's just worn enough to essentially disable reverse gear, but not worn enough to fully disable the OD Gear? (My OD "5th gear" is still operating as I mention in my initial post)

When engaging the Overdrive, I use the clutch about 50% of the time.
I never paid it much mind, as I remember reading a Volvo Manual that said it wasn't necessary.

[esmth]

There is an inner and outer face of the cone "wet" clutch, and a one-way "overrun" clutch. What I think is happening in your case is the inner face of the cone clutch that is engaged with the annulus with OD off is worn out, and in forward gears the overrun clutch is what is transferring all of the forward torque. In reverse, the overrun clutch is not preventing the input from overrunning the output and the inner face of the cone clutch is slipping.

OD will still work in forward gears due to it using the other side of the cone clutch that is not worn out.

I like this website for a basic description of how it works.
https://www.uniquecarsandparts.com.a..._overdrive.php

[tintintin]

Originally Posted by VolvoScout

My OD "5th gear" is still operating as I mention in my initial post

So it works now, not 50% as you mentioned in your initial post?

[VolvoScout]

It work about 75% of the time now, I'd say, but I am attributing that to the "Lucas Oil Stop Slip" I added rather than the solenoid cleaning.

Made a quick video as I pulled/cleaned the solenoid: https://www.youtube.com/watch?v=cxpi...UGV9AC&index=1

I'll probably just swap with the spare Overdrive I have on my parts car and evaluate the worn overdrive over the Winter. Anyone know where I can pick-up new Clutches for the overdrive?

[grumpy dad]

Hi
I like your how to very 1970 so go well with the Volvo
but while you were under there you should have cleaned the mesh filter
its the oblong plate with the 6 bolts in it
undo and you will find a mesh filter
clean and re fit
hope that helps

[VolvoScout]

Thanks.
I cleaned the mesh filter when I did my transmission fluid change over the Summer.
Would it have been advantageous to do it again so soon?

[carver]

Originally Posted by VolvoScout

Anyone know where I can pick-up new Clutches for the overdrive?

Used these two in the past with no issues.

Overdrive Repair Services LTD

OD spares

[planetman]

There are 2 filters inside J and P overdrives.

There's the 1 inside the pan but there's also another filter under the large plug you can access when you have the pan removed. The 2nd filter is where debris from the clutch normally collects.

BTW, we have a NOS cone clutch in stock.

[VolvoScout]

I disassembled my spare orderdrive from my '84 parts car.

Does this clutch look a-ok to put back into the overdrive or does it look too worn and in-need to replacement?

[IMG][/IMG]

[VolvoScout]

Here is the cone clutch from my '84 parts car.
Does this look reusable?

[IMG][/IMG]

[IMG][/IMG]

[hiperfauto]

Both parts look fine.

[VolvoScout]

I am assuming the oil seal goes in here.
The green book says to use a press to disassemble, is there a way to do this without a shop press?

[IMG][/IMG]

[hiperfauto]

The oil seal goes in the back of the tail housing.