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TR4/4A TR4A - A Type OD Solenoid - need a bit of help

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tdskip

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Hi guys - hope everyone is doing well. OK - so here is the deal. The last major thing (thanks to a lot of help from folks here) on the 66 TR4a to get sorted is getting the OD working.

I bench tested the solenoid. Grounded and with power applied it actuates.

In the car (bypassing the lock-out switches for now) I get power at the solenoid lead when the overdrive stalk is actuated. I get 11v at the lead with the car off, and around 12.7v when the car is running.

I can hear the relay clicking.

So that that appears to be all good - except the solenoid is not actually actuating on the car. That is to say that the piston is not actually moving?

Should I be thinking ground on the solenoid? The ground is simply through the solenoid metal face and screws, right?

Other ideas?
 
When you activated it on the bench, did it try to jump off the bench? If not, I'd guess the pull-in coil is not working (a common failure).

The solenoid contains two coils, the "holding" coil only draws an amp or two and isn't very strong. It will move the plunger with no load, but not against the pressure on the OD operating valve.

The "pull-in" coil draws close to 20 amps and is much stronger; but will also overheat very quickly if it remains powered for very long. There is a little pushbutton in the top of the cavity where the plunger moves, so that when the plunger is all the way up, it pushes the button which in turn opens the contacts inside the end of the solenoid and interrupts current through the pull-in coil.

You might be able to coax it back into life by cleaning those contacts and/or finding a broken wire leading to them. But most likely IMO you need a new solenoid. The good news is that they are on sale @ TRF.
 
Hi Randall, good morning. It did click with some vigor, but sounds like not enough. I'll put a brand new one in (having TR4a redundancy is helpful at times) and see how that works.

Thanks.
 
OK - it doesn't appear to be the solenoid. Put a brand new on in / mounted on the car the piston on that one does not actuate either.

I doubled checked the first solenoid with a battery and as soon as power is applied the piston snaps right in.

Update - same solenoid and piston connected to the wiring and no action on the piston even when it is just sitting on the floor board (not installed so there is no resistance on the piston). Good ground on that test, so that suggests <span style="text-decoration: underline">not enough power</span> is getting through, no?
 
tdskip said:
...I get 11v at the lead with the car off...
Click to expand...

Is this your battery voltage? If yes then the battery is low or worse. If you get more like 12.6 at the battery then you're looking for a dirty/poor connection along the way.
 
Was the 11v measured with the solenoid connected? If not, I'd try it again with the solenoid in circuit, and measure right across the solenoid (from the housing to the wire lead). If there is 11v applied and it doesn't suck in the piston even when not connected to the operating lever; then that is a bad solenoid even if it is brand new.

But I agree with Geo, that would also mean you've got a poor connection somewhere that should probably be addressed.
 
That was at the solenoid w.out the car running. Battery is OK. I cleaned the connections at the relay but no change in at the solenoid. So that needs chasing as well.

Battery is OK and charged.
 
OK – starting to dig into wiring again and I have 12v going from the big brown wire into C1 but not going to C2. Cleaned everything again. Swapped the relay and connected all the circuits and I now have 12v to C2 when I activate the OD. Connected everything and it now works, including the lockout when not in the correct gear. Tried the old relay and that worked as well, so it must have been the cleaning that did the trick.

Thanks guys.
 
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