New here - to tackle an old BMW e30 guzzler

[extragoode]

Originally Posted by Christ

Test the wiring first, if you have continuity through the length of the wire, get a JY solenoid and try it out. If that doesn't work, further diagnosis is required.

With the locking switch, if wired properly, and once you re-learn how to drive with it, there will actually be less lock/unlock cycles. Every time you let off your accelerator or hit the brakes, the TCC unlocks. If you have the switch wired properly, it won't unlock when you let off the accelerator to slow down a MPH or two (which you do more than you realize... trust me.), which lessens the cycles the TCC goes through.

It also allows for full-on engine braking, rather than slippage braking. If you engine brake, you'll want to try it out first in low speed situations, because if you leave the TCC lock engaged, it will hit hard and fast (which is actually better for automatics), and it may scare you.

You make this sound a lot more hard core than Joshua did. I'll still look into it and definitely ALWAYS test out any mods at low speed in an empty parking lot before trying them out in traffic. Would lock/unlock frequency thing still hold true if shift into neutral to coast further?

[Christ]

Originally Posted by extragoode

You make this sound a lot more hard core than Joshua did. I'll still look into it and definitely ALWAYS test out any mods at low speed in an empty parking lot before trying them out in traffic. Would lock/unlock frequency thing still hold true if shift into neutral to coast further?

Here's the fuzzy part:

It depends on your transmission.

According to what I've seen/read, it's probably only going to work in one gate of the selector, usually D or OD, unless the transmission was designed to lock in other gears as well. (This doesn't mean you can't make it lock in other gears, it just means that the transmission won't allow fluid to lock the TCC unless you're in a specific range of the selector.)

That being the case, shifting into Neutral will cut fluid flow, and you'll have a solenoid holding open a valve that isn't getting any fluid to it anyway.

If it's a fully electronic transmission, it's a bit different, since it was probably a design feature to allow for TCC lockup in any gear, since it's always in D/OD, with a preference allowed for a specific gear when you manually shift to it. (As I understand it, I could be perfectly wrong, though.)

In that case, you'll be able to leave it locked and still downshift manually for engine braking, but I don't know about using neutral, since Neutral is a bypass valve in the transmission that still allows fluid to be pumped without engaging any drive gear.

However, you won't use neutral as much as you normally let off the gas, so even if it gets cycled a little more often from you using neutral, I'm sure it's still well within the threshold of MCBF (Mean Cycles Before Failure, an average of the number of cycles that the solenoid can perform based on a sample group of units.)