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M46 overdrive woes

ogamer777

ogamer777

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Joined
May 22, 2016
Location
New North Winchestersonville (PNW 425 gang)
1982 244 b21ft m46

So my OD doesn't engage and I've chased this issue for a few months. OD light comes on when I hit the button, I hear the relay and I can hear the solenoid engage as well but the darn thing will not go into OD. I've replaced the solenoid with a brand new unit.

Is this the actual overdrive unit itself gone bad? Or something else? Afaik it's the original m46 with nearly 240k miles.
 
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+ 1 on the piston o-ring seals, that's the second most probable, after wiring issues.

"Gear oil" in the m46 should be ATF Type F (can be harder to find) or SAE 30w non-detergent motor oil. Hopefully you will be able to tell by the color what is in yours.
 
We regularly rebuild J overdrive units and we did one last week.

We normally have all the gaskets and seals in stock as well as a decent collection of used parts.

The last O/D needed a clutch and although new ones are still available, the customer opted for a good used 1 which we had.
 
Dump the clutch in reverse? Wut? I always turn the car off with the trans in fourth with the overdrive engaged and then the overdrive comes off the trans easy and is not hydro locked to the sucker. Just jack up the rear wheels to do this.
 
It's a pretty easy job, I did the manual swap last year and this prompted my rebuild:

kpwrgqcl.jpg


Here's a seal kit for it that you can pick up off of ebay, includes the often forgotten solenoid seals. I picked up the gaskets from Ian.
 
I would first connect the wire to a test lamp and confirm current is making it to the solenoid.
 
There are 3 paper gaskets, but if you want to properly reseal the O/D, there are a number of additional parts that are needed that aren't in that o-ring kit.


Dowdy seal to seal the solenoid to the case
2 copper sealing washers for upper case studs
O-ring for speedometer housing
Small lip seal for speedometer drive gear
Rear seal

There is 1 more seal and that is for the main filter plug and if original, it's an aluminum crush washer. I mention it so you can make sure you find it to reuse as it doesn't always come out when you remove the filter and it can fall out while cleaning and might be over looked or lost.
 
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