Traxxas T-Lock TRA5697 for TRX-4 – Guide

I found only one topic about the TRA 5697 T-Lock module (for summit).

The module allows you to control two servos from one channel.

  • Ch position -100 is all servos “off”
  • Ch position 0 is one servo “on”
  • Ch position +100 is both servos “on”

The problem with TRX-4 is: One servo is the other way around than what they are in the Summit. This means, by using the T-lock with TRX-4 as it is supposed to be used, you get a really funky setup:

  • Ch position -100 front is locked
  • Ch position 0 both are locked
  • Ch position +100 rear is locked

OR if you switch the servos:

  • Ch position -100 rear is locked
  • Ch position 0 both are unlocked
  • Ch position +100 front is locked

And that is what you do not want. You’ll be missing full lock and full open with the stock T-Lock setup which ever way you connect the servos.

What I did:

With my Futaba 4PL (4 fully programmable channels), I use one channel (ch3) for the rear lock ONLY. This allows me to have one button that controls the rear diff only. I can also set the End points for the servo, which maybe means it won’t burn out so quickly.

In ch4 I have the T-Lock system which is hooked to the front lock AND the 2-speed. Now I get:

  • Ch position -100 front is open and slow gear
  • Ch position 0 front is locked and slow gear
  • Ch position +100 front is locked and fast gear

This means whenever I run with fast gear, my front diff is locked. But I am willing to live with that, since I get to run my Futaba radio with front EPA’s etc (and I can also easily drive with one hand which is hard with the TQi).

If someone were to offer this piece (TRA8240) at shapeways where the other servo mount would be flipped, then the T-lock would work out of the box (with open, one locked, both locked functionality).

Hope this helps.

VRC 468x90 Traxxas T Lock TRA5697 for TRX 4   Guide

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