Electrical T5 Neutral Switch Question.

Lyonmt

Member
Nov 17, 2004
110
7
18
Tampa, FL
I bought a used T5 off craigslist. It has the neutral switch on the right side of the top cover. My original has the switch on the left side of the top cover. I tried to swap them, but the old one is a slightly larger diameter than the new one. Does anyone know where I can get this in the correct diameter (I want to keep my cruise control)? Additionally the new one has a square connector which is incorrect for my application, my harness requires the mostly round connector. Though I am not really concerned with this as I can solder on the connector from my old one.

New one: [E5ZR-9E940-AA]:
20151123_194327.jpg

new top cover [13-51-097-901]:
20151123_194748.jpg

Both switches (the connector on the new switch was melted):
20151123_191940.jpg
 
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The NSS has nothing to do with cruse control; That is a function of the VSS (vehicle speed sensor) that is mounted on the speedometer cable.

What the NSS (Neutral Safety Switch) does:
5 speed transmission: It has no connection with the starter, and the engine can be cranked without it being connected.
Auto transmission: It is the safety interlock that prevents the starter from cranking the engine with the transmission in gear.
What it does for both 5 speed and auto transmission cars:
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running computer diagnostic tests. It also checks to see that the transmission is in Neutral (5 speed and auto transmission) and the clutch depressed (T5, T56, Tremec 3550 & TKO)). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.
 
With the NSS disconnected, you will not be able to dump the engine running codes and you will get a code 67 when you dump the codes. There are also some idle problems associated with a malfunctioning or missing NSS.
 
The T5 and NSS may have come off of a GM car or even a Jeep. Take the old sensor to the auto parts store and see if they can match it up for you.
 
The body has a part number for a Mustang Trans, same as my stocker. However, the top cover looks to have been changed. I wish I could find the correct thread as I don't have a lot of confidence that I can re-thread the hole thing and it looks like it uses all of the threads.
 
I'd venture to guess that's not a Mustang T-5. You might want to ID it first before bolting it in.

The part numbers cast into the body and cover are part numbers for those actual components they are physically cast into, so it's possible to have numbers match for various things like the case.

There is a tag usually bolted to the tailhousing that will have the relevant info stamped into it. This will ID the trans. If it's missing, well the job gets a lot harder.
 
I'd venture to guess that's not a Mustang T-5. You might want to ID it first before bolting it in.

The part numbers cast into the body and cover are part numbers for those actual components they are physically cast into, so it's possible to have numbers match for various things like the case.

There is a tag usually bolted to the tailhousing that will have the relevant info stamped into it. This will ID the trans. If it's missing, well the job gets a lot harder.


I checked the number on the case and it shows that it is for an 1986-1991 Ford WC

Top Cover CASTING NUMBERS:
13-51-097-901 85 Ford w/neutral switch on RIGHT SIDE

So where do you get one of these oddballs?

I was gonna try a transmission shop, *shrug* before I buy a regular one and try to tap it down to fit.
 
Just perusing my tremec manuals.

World Class T-5's have the NSS on the left side of the case

Non-WC T-5's have it on the right side of the case. These are usually older, pre-1986 Transmissions.


based on that, I would venture to guess you need to find an NSS for a 1984-1985 T-5 and then solder the post 1986 NSS plug onto it since the electrical connections are different.

This is a T-5 I yanked out of a 1985 Mustang. You can see the plug on the right side and the difference from the later connector
pic.php
 
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So after a bit of research I found that this is a one year only switch that they only used on the 1985 model. further research found that Todd at Prestige Mustang in Monroe GA has one for $50. However, since I am on a shoestring budget and from what I can tell, most people think that it won't make a difference with the idle; I bought a pigtail connector that I am going to use to close the loop and bypass the NSS.

Special thanks to Matt at NPD for taking the time after hours (sitting in his driveway actually) to discuss this with me at length. That kind of customer service is very rare in this day and age!