Neutral Stop Safety Switch

[bkahler]

Since I'm making the swap from a TH400 to the 4L80e I've been sorting through the wiring issues. In 1974 on the motorhome chassis GM used a Neutral Stop Safety Switch (NSSS) that fastened towards the left side rear of the transmission and was activated by the linkage movement. That transmission was long gone before I got the Argosy so other than sketches in manuals I've not seen a picture of one.

The 4L80e that I got from the 94 box truck never had any sort of NSSS mounted on the transmission and I can see no means of mounting one, i.e. none of the mounting bosses have tapped holes for mounting a switch so I am surmising that in 1994 GM put the NSSS in the steering column.

The 84 & 86 motorhomes that I'm familiar with did not have any NSSS mounted in the steering column yet I don't remember seeing any NSSS on the side of the transmission. That doesn't mean they didn't have one, I just never noticed it.

Any suggestions on what would be the best way for me to incorporate a NSSS on my Argosy using a 4L80e transmission?

Would a later steering column NSSS bolt on to my steering column and work?

Thanks!

Brad

[martin300662]

Originally Posted by bkahler

Since I'm making the swap from a TH400 to the 4L80e I've been sorting through the wiring issues. In 1974 on the motorhome chassis GM used a Neutral Stop Safety Switch (NSSS) that fastened towards the left side rear of the transmission and was activated by the linkage movement. That transmission was long gone before I got the Argosy so other than sketches in manuals I've not seen a picture of one.

The 4L80e that I got from the 94 box truck never had any sort of NSSS mounted on the transmission and I can see no means of mounting one, i.e. none of the mounting bosses have tapped holes for mounting a switch so I am surmising that in 1994 GM put the NSSS in the steering column.

The 84 & 86 motorhomes that I'm familiar with did not have any NSSS mounted in the steering column yet I don't remember seeing any NSSS on the side of the transmission. That doesn't mean they didn't have one, I just never noticed it.

Any suggestions on what would be the best way for me to incorporate a NSSS on my Argosy using a 4L80e transmission?

Would a later steering column NSSS bolt on to my steering column and work?

Thanks!

Brad

I guess it prompts a follow-on question from me, of what are you going to use the select gears on the 4L80E? I see there are TH400 linkage to 4LxxE adapters - maybe they have the switch mounted on them?

[bkahler]

Originally Posted by martin300662

I guess it prompts a follow-on question from me, of what are you going to use the select gears on the 4L80E? I see there are TH400 linkage to 4LxxE adapters - maybe they have the switch mounted on them?

On the 91-94 4L80e transmissions the shift range selector is basically the same as the TH400. The later transmissions were cable shifted which is what you're probably referring to. From what I've been able to find so far all I really need to do is lengthen the shifter rod that comes from the steering column about 3" and tweak the angle slightly. That's the easy part

The original TH400 in my Argosy (and probably yours) had a switch on the left side rear of the transmission that was used as the Neutral Safety Stop Switch. From what I have found it was specific to the motorhomes or P30 chassis vehicles. Mine is long gone and likely wouldn't bolt to a 4L80e anyway.

The 95 and up 4L80e transmissions had what is called an MLP switch located on the side of the transmission and worked in conjunction with the shift range selector shaft. The bosses for mounting that switch are not drilled on my transmission and the shaft sticking out of the transmission is not long enough to allow the switch to be used. At least I don't think it's long enough and I plan to verify that.

I did find one forum where someone had the same issue and they modified their steering column by adding a hole in the steering column for the Neutral Safety Switch and then welded a tab on the shaft inside to trigger it. That's what I'm going to be looking into this weekend. If I can go that route then problem is solved. If not I'll have to keep looking!


Brad

[martin300662]

I thought you had to install a shift kit like this one Brad (http://www.shiftworks.com/4lx.htm) to get over the fact that we only have drive, 2, 1 selection.

The kit in the link comes with the option of a NSS

[bkahler]

That might be one approach if nothing else was available. Tonight I looked closer at the 1986 steering column that I had transplanted into the Argosy and found this



It's been several years since I installed the column and didn't realize at the time what the switch was. At the time that wasn't something I was to concerned about. Apparently at some point GM stopped putting the NSS on the transmission and moved it to the column. I know my 74 steering column does not have the NSS installed and I'm betting your 75 doesn't and I wouldn't be surprised if Matt's 76 didn't have the NSS on the column either.

It appears that on the 4L80e transmissions starting in 1995 GM moved the NSS back to the transmission and called it a MLPS.

You might want to check your donor and see if the steering column has the switch mounted on it. If it does at some point before it goes away for good you might try and salvage the column.

The bad news is I spent over a day worrying about the problem. The good news is I didn't have to do anything to fix the problem

[martin300662]

I will definitely check the column on the donor Brad

[bkahler]

Since you're looking at later engine/transmission combos the switch will likely be included with the transmissions like the 95 and up 4L80es have.

But it wouldn't hurt to know what you have available, just in case

[martin300662]

I think my 'swap' options are simple....

I am keeping my fingers crossed the little 350/TH350 hold out until it gets back to UK.

If it does I am going the try and pick up a 8.1L/Allison in a running vehicle and ship that as well (so I have all the parts to do the electronics swap).

If my luck runs out and we have to swap sooner then I can only install another 350 (probably a (#19210009) 350HO/(#19260380) 4L65E/(#19212657) transmission controller), so that the specification is the same as a VIN for registration in UK.

If I can't find a suitable 8.1 I think will buy and ship the 350HO/4L65E/controller with Bella so I am ready for the inevitable.

[J. Morgan]

http://www.yogisinc.com/index.cfm/pa...06/prd4206.htm




Talis gentium ceciderunt.

[J. Morgan]

https://www.premierstreetrod.com/det...witch_Kit.html




Talis gentium ceciderunt.