Transmission relay constantly "clicking"

[rbdave]

Hi Everyone,

I have been troubleshooting an issue that led me to replace the CDL actuator.

I have a 1996 series 80 with a CDL switch installed, no 7 pin mod.

I replaced the center diff lock actuator. It works great now. But, the transmission relay,the switch that controls the actuator, keeps chattering--clicking off and on, over and over again. I am 110 % certain that is the part that is making the noise. I can feel it, hear it chattering when in gear, at idle, or any RPM.

It does NOT make noise when the CDL is engaged. It also does NOT make noise when the CDL switch is unplugged.

I did troubleshoot the switch by plugging in the hazard switch in its place, and it does make the chattering noise with the hazard switch plugged in, confirming the the switch is not the issue.

I replaced the Transmission relay, and the new one behaves the same.

Has anyone experienced this? I am thinking i might have a short in the system somewhere, but dont know where to start.

Thanks guys, hope someone can shed some light on this, and help me with a starting point.

Thanks,

 

[Offroads4x4]

I would start by cleaning all the electrical connections to the trans with electrical connection cleaner and then use dielectric grease in the connections before reconnecting them.

 

[Drune]

Hi Everyone,

I have been troubleshooting an issue that led me to replace the CDL actuator.

I have a 1996 series 80 with a CDL switch installed, no 7 pin mod.

I replaced the center diff lock actuator. It works great now. But, the transmission relay,the switch that controls the actuator, keeps chattering--clicking off and on, over and over again. I am 110 % certain that is the part that is making the noise. I can feel it, hear it chattering when in gear, at idle, or any RPM.

It does NOT make noise when the CDL is engaged. It also does NOT make noise when the CDL switch is unplugged.

I did troubleshoot the switch by plugging in the hazard switch in its place, and it does make the chattering noise with the hazard switch plugged in, confirming the the switch is not the issue.

I replaced the Transmission relay, and the new one behaves the same.

Has anyone experienced this? I am thinking i might have a short in the system somewhere, but dont know where to start.

Thanks guys, hope someone can shed some light on this, and help me with a starting point.

Thanks,[/QUOTE

I know it’s been a while, but I would love to know what you found on this. Currently same thing exactly with a 94 but I do have the 7 pin mod. It did this before and after the mod, also with a blown fuse (the 30 amp “diff” fuse) and with a good fuse. This thing is giving me fits! Any help would really be appreciated.

 

[agp35]

I know it’s been a while, but I would love to know what you found on this. Currently same thing exactly with a 94 but I do have the 7 pin mod. It did this before and after the mod, also with a blown fuse (the 30 amp “diff” fuse) and with a good fuse. This thing is giving me fits! Any help would really be appreciated.

Bumping this thread back from the dead, wondering if anyone found a solution to this?

96' LX450 with a pin 7 mod.

Actuator was bad and has been replaced, working as it should, but getting chatter from the relay. Tried a new relay and same noise from it. Doesn't chatter when center diff is locked, or the dash lock switch is unplugged. Tried the hazard switch in its place and same thing.

Doesn't chatter at idle or low throttle, but anything over ~20% throttle it does.

Edit: restored pin 7 to the transmission control relay to see if that would solve anything, and same result. Chatters unless the CDL dash switch is unplugged.

Oddly enough, I can still lock the CDL in high gear which I'm guessing shouldn't be the case without the pin-7 mod?

With the switch unplugged and shifted into low, the CDL locks as it should, but won't unlock unless I plug the dash switch back In and turn it off that way

 

[ppc]

Oddly enough, I can still lock the CDL in high gear which I'm guessing shouldn't be the case without the pin-7 mod?

The pin 7 mod has nothing to do with locking in high range. That mod only disables automatic locking when shifting to low range.

 

[Evil80Forces]

Im bringing this back from death to comment since I don’t see anyone resolving it yet.

Im having the same issue, and I think it’s what has lead to burning up the actuator motor too.

I finally pulled the transmission relay and it failed a bench test, specifically between terminals 6 and 7, the ones with the diode that will only give continuity a certain direction.

I have a other tested good relay coming in the mail so will see if that fixes the issue.

It’s been driving me crazy.

 

[Evil80Forces]

Bumping this thread back from the dead, wondering if anyone found a solution to this?

96' LX450 with a pin 7 mod.

Actuator was bad and has been replaced, working as it should, but getting chatter from the relay. Tried a new relay and same noise from it. Doesn't chatter when center diff is locked, or the dash lock switch is unplugged. Tried the hazard switch in its place and same thing.

Doesn't chatter at idle or low throttle, but anything over ~20% throttle it does.

Edit: restored pin 7 to the transmission control relay to see if that would solve anything, and same result. Chatters unless the CDL dash switch is unplugged.

Oddly enough, I can still lock the CDL in high gear which I'm guessing shouldn't be the case without the pin-7 mod?

With the switch unplugged and shifted into low, the CDL locks as it should, but won't unlock unless I plug the dash switch back In and turn it off that way

Did you ever find the reason for the relay chatter?

 

[Evil80Forces]

I know it’s been a while, but I would love to know what you found on this. Currently same thing exactly with a 94 but I do have the 7 pin mod. It did this before and after the mod, also with a blown fuse (the 30 amp “diff” fuse) and with a good fuse. This thing is giving me fits! Any help would really be appreciated.

ever figure it out?

 

[agp35]

Did you ever find the reason for the relay chatter?

I have not. Random starter issues have been taking up most of my time recently so I haven't had a chance to mess with it.

After a month or so with the new actuator in, it had stopped working. I tried figure 8's, cycling between high and low, and everything else I could think of to no avail. Got tired of trying to find the issue in the wiring so I bought a replacement harness that goes from the firewall to the trans and transfer case and all their sensors, but I received the wrong harness and that is the last I messed with it. Now that the weather is nicer, I hope to dig into it again whenever I get the time.

Any luck finding out about the chatter yourself?