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MG TD TF 1500 - TF reverse light - transmission switch

Went to hook-up the reverse light today after gathering all the proper wires, connectors, light bulb, fuse and other assorted bits. I had installed the transmission switch (Moss) and pre-wired it some 20 years ago anticipating installing a reverse light some day. I went to test it...and it does not work. Put the transmission in reverse and did a continuity check with an ohmmeter. For the most part it does not work. If I jiggle the wires and the shifter I get SOME brief continuity but mostly none. I suspect it's the switch. That said, had anyone installed the Moss switch and has it worked as expected? When I installed the one I have, I just screwed it into the transmission. I don't recall having used of needed a washer as one was not indicated as being needed.

Not sure of the quality of the Moss part. I've had issues with other parts I've bought from them in the past. Has anyone used an alternate supplier/switch?

Jim
Jim Rice

Maybe best to remove the switch from the g/box and test it for on/off,then if it's ok it may just be a case of determining the washer thickness required to get it operational.
William Revit

William:

It would seem (at least initially) that adding a washer would distance the gearbox actuating mechanism further away from the switch detent button making it less likely to fully close the switch contacts. Of course my logic/thought process has not always been spot-on, so I will play with it some anyway to see how it actually works. That said, just getting to the switch in the 1st place will be a task. I can see why some would opt for a remote toggle switch as an alternative.
Jim Rice

Jim,
It is easy enough to get at with the seat base removed.

Regards
Declan


Declan Burns

If you install that switch, do you have to cut an access hole in the transmission cover?
L E D LaVerne

Laverne,
No, you can take the wiring out underneath the floorboards.
Regards
Declan
Declan Burns

LED:

The transmission cover has a couple "bump-outs" on the driver's side meant to accommodate the installed switch. (see below link)

http://www.mg-cars.info/mgtd-mgtf1500-bbs/tf-reversing-light-switch-2016120400563625582.htm

As the narrative stated, this is on a TF. I don't know if the transmission cover was the same on the TD's. There were other discussions on the type of switch used. Like what Moss offers (P/N: 140-470), the blade connections stick out straight from the switch. Connecting the wires using that type switch MAY interfere with the transmission cover. As you can see in the pictures in the link, the switch being used orientates the connectors differently, so the bump-out gives the needed clearance with that type switch. I suppose you could cut a hole in the transmission cover if clearance was an issue, but then the carpet backing would be exposed to the elements unless a sub-cover of sorts was fashioned to cover the hole in the transmission cover.
Jim Rice

Is this a T type transmission? I did not know that MG added a reverse light switch until the late Mk1 MGBs in 1967
Bruce Cunha

Bruce:

I believe it was an option, as it was not a legal requirement to have a back-up light up through the TF at least. However, MG did provide a threaded plug on the transmission you can remove, and add the switch if you wanted to add a reverse light. The wiring harness does not include leads for the reverse light.
Jim Rice

I used an MGB switch if I recall correctly.
Regards
Declan
Declan Burns

Jim,

The original Lucas part number for this switch is 31077(X) (where X is some letter). They were fitted as standard to Y types. Also they were used as overdrive position switches on Jaguars. If I were you I would find the original part. Two are on Ebay USA at the moment. 154912208619 You also need to fit a fibre washer to prevent oil leaks. I have one of these switches in my spares box, I intend fitting it next time the box is out.

John
J Scragg

John:

Thanks for the heads-up and clarification. Hugh Pite had seen my post and offered up an original switch. Looking at the pictures and his description, it matches the switches you reference currently on E-bay, and it came off a Y-type. The connecting posts are the same as those on the fuse block and voltage regulator, so a bare wire end inserted into the slotted post and secured with the screw. Simple and sweet!

That said, it looks like a number of reversing transmission switches would work. The Moss version, the one used in the link I referenced earlier, and the original off the Y-Type gearbox....maybe others as well?

FYI for the group: If anyone is looking to install a reverse light and needs a switch, the 2 that John references are currently still available (E-bay item # 154912208619) and another one (Part number 31849A, E-bay item # 284875086668) off a Jaguar E-Type. That one is the same as the switch pictured in the earlier link I posted. The Moss switch is currently showing as back-ordered.
Jim Rice

Thanks Jim. That is interesting because when I was looking for an OD transmission for my 67 B. I had to look for a late 67 as the earlier OD's did not have a reverse light place on them. My 67 was built towards the end of the MK1 MGB's and did have reverse lights.

Interesting that they were looking at is as early as the TF, but did not add it to later transmissions.
Bruce Cunha

This thread was discussed between 10/09/2022 and 14/09/2022

MG TD TF 1500 index

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