GB 42 Transmission Temp SW Questions

[JESSEDIVER49]

I bought a 1984 GB 42 with twin Lehman 120s about 15 months ago. It has 4-yr old rebuilt Borg Warner transmissions and I noticed each transmission has what appears to be a temperature switch. My question: Are the transmission temp switches tied to same audible alarm as low oil pressure? i.e. a common "something is wrong" sounding alarm? If so, shouldn't I be able to test the switch by a jumper across the terminals on the switch mounted on the transmission? Do most cruisers install temp indicators on their transmission? at least a local indicator?

 

[hmason]

I have owned 2 GBs and never saw a temp alarm or switch on the tranny(s).

 

[Xsbank]

It's probably the neutral switch. Unless you are in neutral you can't crank your engine.

 

[Marlinmike]

I agree with the above, most likely you are seeing a neutral safety switch, is it right where the shift linkage is?

I have seen over temp switches on later models transmissions, if over heat would sound the buzzer, same buzzer as the oil and engine temp, so you would need to really look at the gauges and if all was good most likely the tranny.

 

[Marin]

It's probably the neutral switch. Unless you are in neutral you can't crank your engine.

This component must vary from boat to boat. Ours does not have these-- never did according to the boat's manual and schematic-- and I've not talked to a GB owner whose boat did either. But it's very possible some do.

 

[Xsbank]

My 32 had one.

 

[kchace]

On those transmissions the neutral switch is directly opposite the shift linkage. I know my boat has them. Temp alarm switches were offered as an option, not sure which hole they would mount in.

Ken

 

[C lectric]

PICTURE?????

Otherwise we are actually just guessing. Likely it is a neutral safety switch especially if it is screwed into the gear casing.

There are temperature sensitive snap switches which can, are, used for alarms but need to see.

 

[Capt.Bill11]

It's not at all uncommon for GBs to have tranny temp alarms. In fact many have an alarm panel with Amber lights for eng. temp., oil press., tranny temp. and sometimes one or two lights for other alarms or to show that the engine room lights are on.

The tranny temp sender is mounted down low on the right side of the tranny as I recall.

 

[JESSEDIVER49]

GB Transmission switches

Thanks for comments. Actually, each transmission has 2 switches, looking from engine toward shaft/prop, one sw is at 12 o'clock and second switch is at 9 o'clock. I contacted Velvet Drive office tech support. He said most likely, one is neutral safety sw and other is high temp switch but couldn't tell me where indication would be since that's an owner decision.

I'm thinking likely alarm is same buzzer as oil pressure as several have suggested. I guess I can test this out but haven't tried yet.

 

[Xsbank]

Pull the leads off it, attach your ohmmeter and move the gear lever. That'll tell you if it is the neutral switch or the temp switch.

 

[Capt.Bill11]

The neutral switch is on top across from the gear lever. As I believe someone else pointed out.

Look on page 4.

http://www.marinemechanic.com/fpdb/Borg-Warner-Velvet-Drive-71C-72C-Transmission-Owners-Manual.pdf