Kickdown solenoid

[TomoHawk]

On my 280Z, the trans (Jatco 3NL41B) will only kickdown occasionally under high vacuum conditions (at any speed), and I've never heard the kickdown solenoid clicking, so I checked it out.

BTW- the trans was totally 'rebuilt' a couple years ago, and only has about 2,000 niles on it since.

I checked the voltage at the switch: 12.2 volts, which is just a hair less than the battery. Then I put a shunt wire direct from the battery to the solenoid wire where the switch is on the gas pedal. Still no solenoid click.

If the kickdown solenoid does work, then the only thing I can think of is that the solenoid doesn't have a god ground. Since I can't get under the car, I will have to get it to the trans shop and have the guy check the solenoid.

Unless there is something else to try.

thxZ

[sblake01]

The downshift solenoid is probably the culprit. I had a 77 200SX with essentially the same trans and went through that same problem. Probably not the ground since they are grounded by their mounting. When I pulled the solenoid, I couldn't get it to click by applying 12 volts to it. Bought a new one, insatlled it and the problem was solved.

[sblake01]

Is that the stock trans? I thought a 78 would have a Jatco 3N71B.

[TomoHawk]

Yeah, I forget the number. I was thinking of the Maxima trans.

I was going to add some ground wires to the engine to improve the electricals, and the transmission is one thing to get better grounded.

thxZ

[dk240z]

Good luck! I had to by one two months ago(it leaked tranny fluid), and it was 98$ from Nissan. Try another parts house.

DK

[sblake01]

On the note of adding extra grounds: I still don't get it. I guess I'm old school. I have never in my life added extra grounds to a car and I've never experienced and ground related problems. I just make sure that the grounds that already exist are good. The factory did a pretty good job building these cars. Why would your transmission need extra grounding? I think I paid like 68 bucks for that solenoid but that was 9 years ago. 31941-X0103 is the part number and I seem to recall not being able to find it at a Autozone/Kragen/Pep Boys type store.

[TomoHawk]

I am just concerned with the ground connections between things like the engine & body, trans & body, etc. Those things which could be isolated with rubber bushings.

I usually do take my Dremel with a wire brush to any exposed connectors that don't look like they would make a good ground, and shine them up a little.

[sblake01]

To each his own. The factory grounds work and things are not as 'isolated' as you think. Switches on a transmission, auto or stick, are just completing the circuit when closed anyway.

[TomoHawk]

Thanks for the part #. RockAuto doesn't have it, but maybe Autozone will.

thxZ

[sblake01]

Nah, checked Autozone and CSK. They don't have it. You might end up having to bite the bullet and order it from Nissan. That's the only place I was able to find one.

[TomoHawk]

My local Nissan dealer has them for about $100, and it needs to be ordered. The local trans shop had a used one, which didn't look nice enough to buy.

Edited July 3, 2009 by TomoHawk

[TomoHawk]

No good luck for me today.

I took the car to a friendly service place and after the guy took out the old unit, he took out the new one and it had a bent shaft. Nicks on the shaft show somebody jammed it into a hole and bent it. $50 to find out the new solenoid is damaged.

So the Nissan guy ordered an exchange, but the Z guy is on vacation, so I might have to go back to the service place again for another $50 job.

The oddthing that still gets me isthat since the same transmission was used on so many different cars and trucks, that the parts likethe kickdown solenoid would be more readily available still.

Edited August 13, 2009 by TomoHawk