Reverse switch help - Defender Source
Defender Source  

Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Join the Defender Source Community Today
Reply
 
Thread Tools
  #1  
Old December 23rd, 2013, 07:43 AM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
Reverse switch help

So as I've documented here before, I need a new reverse switch on my tranny. No power at bulb, check power is getting to switch, but not through when engaged in reverse.

I believe I have an R380 based on my research here discussing the tranny shift pattern ( im a noob having purchased truck 6 months ago). I've gone to local auto zone and Rovahfarm to get a switch. Both times I've received a switch as depicted on the left with part number AMR3918.

The switch I pull off is located to the right in the photo. Does someone recognize the switch? Do I have a different tranny?
Any help would be appreciated.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	288
Size:	110.6 KB
ID:	86577  
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old December 23rd, 2013, 07:45 AM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
Ok
I'm goofed up and the photo flipped upside down. Read left as right and right as left in the above post. Sorry
Reply With Quote
Sponsored Links
Advertisement
 
  #3  
Old December 23rd, 2013, 09:04 AM
NPT90's Avatar
NPT90
Status: Offline
JT
D90 óriginalé
Member
 
Join Date: Apr 2011
Location: DC/MD
Posts: 2,308
Registry
put your meter on the old one and check for continuity.

I mean push the plunger and see if your meter beeps or you get a reading.

Not doubting you on the power but I am trying to figure out how you would get a reading with reverse engaged. You'd have to hold one lead to the tranny case while holding the positive to the switch. Just for shits and giggles use the resistance test on the existing switch.

It sounds more like a ground problem at the reverse light housing (wouldn't be surprised, english garage mechanics like to use electrical tape and wrapped wires... horrible electricians)
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old December 23rd, 2013, 10:42 AM
sonoronos's Avatar
sonoronos
Status: Offline
Ed
None
Member
 
Join Date: May 2010
Location: Arlington, VA
Posts: 4,959
Hey Joe,

The old switch you pulled is for an LT77.

The new switch you have is for an R380.
Reply With Quote
  #5  
Old December 23rd, 2013, 12:52 PM
mikeslandrover's Avatar
mikeslandrover
Status: Offline
Mike Hammond
110 200Tdi and a 2005 Scorpa SY250
Member
 
Join Date: Oct 2003
Location: Oxted, Surrey, England, U.K
Posts: 1,753
Registry
Quote:
Originally Posted by SimpleJack View Post
So as I've documented here before, I need a new reverse switch on my tranny. No power at bulb, check power is getting to switch, but not through when engaged in reverse.

I believe I have an R380 based on my research here discussing the tranny shift pattern ( im a noob having purchased truck 6 months ago). I've gone to local auto zone and Rovahfarm to get a switch. Both times I've received a switch as depicted on the left with part number AMR3918.

The switch I pull off is located to the right in the photo. Does someone recognize the switch? Do I have a different tranny?
Any help would be appreciated.
Lt 77 reverse is to the left of 1st gear.
__________________
Mike Hammond
Diesels.....great when they're going and so easy to work on.
Reply With Quote
  #6  
Old December 31st, 2013, 11:27 PM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
I'm gonna try to sort this out tomorrow, but I definitely have reverse below 5th gear on this truck. Is it possible that my truck(#357) was between the LT77 and R380. LR nstalled the R380 but tapped the casing to accept the LT77 switch? I don't know how that would work as they seem to be different lengths...

Could I have a non Defender tranny from say a Disco that the PO installed?

Are there any markings on the casing or elsewhere that can help me figure out what tranny I have? Not that it changes the fact that I need a switch from an LT77, but it may help me in the future as issues come up.
Reply With Quote
  #7  
Old January 1st, 2014, 12:05 AM
DannyboyUpstate's Avatar
DannyboyUpstate
Status: Offline
Danny Harrington
1983 110 3-door
Member
 
Join Date: Oct 2013
Location: Albany, NY!!
Posts: 395
Registry
Reverse switch help

It seems that someone bought the switch for an LT77, it wouldn't fit your R380 gearbox, then re-tapped the R380 to hold the wrong switch. Then when the switch didn't work in the wrong gearbox, they just gave up.

Edit: On second thought, that's not likely. The thread of the R380 sensor is so much larger.
Reply With Quote
  #8  
Old January 1st, 2014, 12:10 AM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
I sure as hell hope not.
Don't know if that was even possible as the R380 switch has more girth, they wouldn't be able to tap for a smaller girth switch or at least I don't think that's possible unless LR did it at the factory with the casing.
Just wondering if anyone else has run into this issue? Or has ideas on what I have here.
Reply With Quote
  #9  
Old January 1st, 2014, 03:53 AM
mikeslandrover's Avatar
mikeslandrover
Status: Offline
Mike Hammond
110 200Tdi and a 2005 Scorpa SY250
Member
 
Join Date: Oct 2003
Location: Oxted, Surrey, England, U.K
Posts: 1,753
Registry
1) Does the switch you pulled actually work if it's wired in but not fitted - you manually depress the plunger?

2) Select reverse with the LR stationary and poke a thin screw driver into the hole to get a sense of how far the switch has to reach to be activated by selecting reverse. The R380 switch looks to have a much longer reach into the gearbox compared to the LT77 switch you pulled. Then set the switch up by carefully screwing it in until the reverse light illuminates reliably when reverse is selected.(Disconnect the wires while winding in/out.)

3) Take some good pics of the transmission if this doesn't work.

Final thought, the hole for he reverse switch is drilled straight into the casing, there's no adapter to switch from the larger diameter threat on the R380 type switch to the narrower diameter thread LT77 type switch?

Having googled LT77 I get these images
Attached Thumbnails
Click image for larger version

Name:	reverselightswitch001.jpg
Views:	1080
Size:	118.9 KB
ID:	86997   Click image for larger version

Name:	reverselightswitch004.jpg
Views:	357
Size:	74.5 KB
ID:	86998  

Click image for larger version

Name:	reverselightswitch005.jpg
Views:	1036
Size:	109.3 KB
ID:	86999  
__________________
Mike Hammond
Diesels.....great when they're going and so easy to work on.
Reply With Quote
  #10  
Old January 1st, 2014, 10:19 AM
Roadsiderob's Avatar
Roadsiderob
Status: Offline
Robert Dassler
1994 D90
D-90 Source Vendor
 
Join Date: Apr 2004
Location: Albuquerque, NM, USA
Posts: 993
The switch in your original post is from an LT77. It should have come out of the back of the top shifter assembly. The reverse switch for an R380 is located on the left side of the aluminum extension case...so, a little lower & around the corner from where you pulled that switch. What I expect has happened is that someone has swapped an R380 in place of the LT77 and used the LT77 top shifter. This is not a problem as the castings for the top shifters are the same & they will interchange with slight modification. I have done this several times. The reverse switch was probably left in the top shifter to plug the hole so it doesn't leak oil. It is never being actuated as the shift patterns are different...you would have to get the lever up next to first to actuate that switch. The R380 case is 3 pieces. There is a cast iron front section, a cast iron center plate, and an aluminum extension case. You need to look at the left side of the aluminum extension case near the top. There will either be another switch with a wire pigtail that is disconnected or a plugged hole in the side of the case. Hook up this switch or install the new R380 switch in this hole if the switch is missing. Note: there is also a bypass block for the oil on the left side of the extension case. It is held on by 2 bolts. It may have a 2 wire temp sensor on top of it that isn't used. Do not mistake this for the reverse switch. The reverse switch will be above this. If the R380 reverse switch is present, it may have a connector on the end. Feel free to cut off the connector and put on spade terminals if necessary to connect to the car harness. If there is a plugged hole and you have to install the switch you bought, remember that the switch should have a crush gasket (14mm, I think). You should be able to get this at NAPA.

Edit: Also, thinking about it a bit more.....my 1994 has 2 unused wires in the harness (white, I think) that have spade terminals that are tucked away in that area. If you find the R380 reverse switch actually connected to a pair of white wires, disconnect them and hook the R380 reverse switch to the green & green/brown that you disconnected from the LT77 reverse switch. The white wires are just extra in the harness & don't do anything, but someone may have mistakenly plugged them in as they are in the correct area and look like they should be connected. Let me know if that doesn't make sense and I'll try & get a picture.

Edit again: I see your truck is number 357. Mine is number 391 and has an LT77. I can say with reasonable certainty that your truck left the factory with an LT77. Lots of them have been converted to R380s for various reasons. If you have any question what transmission you have, post the serial number and I will tell you what it is. The transmission serial number is stamped on a cast oval pad on the main case, just forward of the drain plug on the right side. If reverse is below 5th, you have an R380.
__________________
Rob Dassler
SWR Automotive
505-872-7818 (shop)
Reply With Quote
  #11  
Old January 1st, 2014, 12:12 PM
mikeslandrover's Avatar
mikeslandrover
Status: Offline
Mike Hammond
110 200Tdi and a 2005 Scorpa SY250
Member
 
Join Date: Oct 2003
Location: Oxted, Surrey, England, U.K
Posts: 1,753
Registry
Good info Robert, if that doesn't sort it nothing will. I've learn't from that, thanks.
__________________
Mike Hammond
Diesels.....great when they're going and so easy to work on.
Reply With Quote
  #12  
Old January 1st, 2014, 06:49 PM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
Mike and Robert - Thanks for the help. I checked on the left side of the tranny and lo and behold found the AMR 3918 reverse switch. Whats weird is that it wasn't wired to anything, but the dummy LT77 switch was wired to the reverse light wiring. I guess I have been driving around without a reverse light for the past 7 months and didn't know it until recently. Anyways I wired the reverse wiring to the side mounted switch and not the dummy/plug.
You guys rock. Im all sorted out now (or at least the reverse light is).
Robert - Whats the benefit of using the upper casing like the PO did and you mentioned in your post?
Reply With Quote
  #13  
Old January 1st, 2014, 07:12 PM
DannyboyUpstate's Avatar
DannyboyUpstate
Status: Offline
Danny Harrington
1983 110 3-door
Member
 
Join Date: Oct 2013
Location: Albany, NY!!
Posts: 395
Registry
Wait, so you had 2 reverse switches in the one transmission?
Reply With Quote
  #14  
Old January 1st, 2014, 07:19 PM
Roadsiderob's Avatar
Roadsiderob
Status: Offline
Robert Dassler
1994 D90
D-90 Source Vendor
 
Join Date: Apr 2004
Location: Albuquerque, NM, USA
Posts: 993
Jack,
The only benefits to modifying and using the LT77 top shifter on an R380 are cost & convenience. If you are converting an LT77 to an R380 and the R380 did not have a top shifter, it is easy and (almost) free to convert the LT77 part to fit. The castings and shift rod are the same, but there are 3 differences. There is a spool retainer bolted to the underside of the LT77 shifter that must be removed. The detent assembly bolted to the side of the shifter needs to be removed or gutted. I remove it and plug the hole with a 21mm freeze plug. The reverse light switch can be removed and the hole plugged with a short bolt or it can be ignored and left in place to plug the hole. Other than that, they are the same.
__________________
Rob Dassler
SWR Automotive
505-872-7818 (shop)
Reply With Quote
  #15  
Old January 1st, 2014, 08:27 PM
SimpleJack's Avatar
SimpleJack
Status: Offline
Joe
94 D90 NAS ST
Member
 
Join Date: Apr 2013
Location: Arlington, VA
Posts: 147
Registry
Quote:
Originally Posted by DannyboyUpstate View Post
Wait, so you had 2 reverse switches in the one transmission?
Yes. As Robert describes in the post above, seems the PO converted from an LT77 to an R380 and used the LT77 top shifter in the conversion. In order to do this the LT77 reverse switch was carried over to be used as nothing more than a plug. The problem is that the PO or a service shop wired up the LT77 switch and not the R380.
Reply With Quote
  #16  
Old January 1st, 2014, 08:29 PM
DannyboyUpstate's Avatar
DannyboyUpstate
Status: Offline
Danny Harrington
1983 110 3-door
Member
 
Join Date: Oct 2013
Location: Albany, NY!!
Posts: 395
Registry
HA! How the mystery unravels. How bizarre!
Reply With Quote
  #17  
Old January 2nd, 2014, 07:23 AM
mikeslandrover's Avatar
mikeslandrover
Status: Offline
Mike Hammond
110 200Tdi and a 2005 Scorpa SY250
Member
 
Join Date: Oct 2003
Location: Oxted, Surrey, England, U.K
Posts: 1,753
Registry
Quote:
Originally Posted by SimpleJack View Post
Mike and Robert - Thanks for the help.
You're welcome.
Learning as you go is the best way.
I still learn things after 3 full rebuilds, two of them chassis swaps and 2 engine conversions, the most challenging being 2 1/4 petrol to 3.5 V8 in an 88" Series IIA.
__________________
Mike Hammond
Diesels.....great when they're going and so easy to work on.
Reply With Quote
  #18  
Old January 2nd, 2014, 08:13 AM
Craigd's Avatar
Craigd
Status: Offline
Craig Dickson
1995 D90 Red Soft top
Member
 
Join Date: Sep 2003
Location: Boulder County, Colorado
Posts: 460
Registry
I am impressed with rob's diagnosis and clear instructions on how to fix it!! And all without seeing the vehicle.
Reply With Quote
  #19  
Old January 2nd, 2014, 12:56 PM
rover26c's Avatar
rover26c
Status: Offline
Lee
1994 D90 ST
Member
 
Join Date: Jun 2009
Location: NJ
Posts: 764
Quote:
Originally Posted by JSBriggs View Post
Rob is the E.F.Hutton of Rover drivetrains.
Speaking of E. F. Hutton & Co., my colleague now used to work for them. According to her they used to give lavish christmas parties and bonuses.
Reply With Quote
  #20  
Old July 20th, 2014, 03:39 PM
samer0214's Avatar
samer0214
Status: Offline
Samer Hijazi
1986 D110 V8
Member
 
Join Date: Apr 2013
Location: Irvine, CA
Posts: 386
Registry
Resurrecting a bit of an old thread, as I am having trouble identifying the location of my reverse switch, let alone if it's there at all.

Attached are 2 pictures I took of my transmission and highlighted with red boxes. One of them shows a switch towards the top right of the transmission and the other showing a bolt which looks to be newer than the others, as if it was changed or in fact used to plug the hole where the reverse switch is supposed to be located.

I have what I believe to be an LT77 transmission. It is in an '86 RHD Carburated V8, with reverse to the left and up of 1st gear.
Attached Files
File Type: pdf 2014-07-20 12.00.07.pdf (2.00 MB, 41 views)
File Type: pdf 2014-07-20 12.02.12.pdf (2.10 MB, 32 views)
__________________
Thank you - Samer
1996 P38 4.6HSE
Defenderless for now!
Reply With Quote
Sponsored Links
Advertisement
 
Reply

Lower Navigation
Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Tags
switch

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
reverse light switch - Help bneri Defender Technical Discussions 4 September 30th, 2013 01:36 PM
Reverse light switch adjustments StphNieuw Defender Technical Discussions 2 June 18th, 2012 08:24 PM
Reverse Lamp Switch Wiring fleabus Defender Technical Discussions 7 April 16th, 2006 10:58 AM
Can anyone explain what happens after the light switch is turned on? solihul Defender Technical Discussions 3 June 30th, 2005 06:28 AM
Ignition switch jorge Defender Technical Discussions 1 January 10th, 2005 12:12 PM


All times are GMT -5. The time now is 12:27 AM.


Copyright