neutral safety switch

[dodj]

I'm no trans expert but maybe the 'rooster comb' has changed in design over the years and the replacement NSS's on offer were made to work with one specific comb, but are marketed for multiple years?

[chargerdon]

I'm no trans expert but maybe the 'rooster comb' has changed in design over the years and the replacement NSS's on offer were made to work with one specific comb, but are marketed for multiple years?

Maybe... 

Ok got it working, now hoping it doesn't leak (i put teflon tape on the threads first).   What worked for me was NAPA NS6514SB (recommended for 92 dodge truck...i.e a518.   

Four things i noticed:
1) the threaded part is identical in length......but
2) The center prong itself appears to be a little shorter !!  Also, in testing with multi-meter before installing i would get continuity for the outer two points even if i slightly depressed the center prong or the surrounding plastic.  On the other models for "74 challenger" that wasnt the case...just slightly touching it would stop continuity.
3) The NS6514SB comes with a metal washer not a rubber gasket!!   Maybe this is the difference !!  This is the reason i put teflon tape on the threads. 
4) I dont think this is a case of 904/727 vs A518 as i tried the NSNS6514SB in my old 904 sitting on the floor and it works there also!!   I'm thinking its more of a case of there was a design problem going way back, and Mopar redesigned it to work better in the latter years when the a518 came out ...but the part stores still carry the old style. 

Or Hell i don't know...just happy that the one for the A518 works !!

[Katfish]

Glad to hear it's working.
Any issue with the electrical harness connection?
The online pics seem to show the 3 pins coming out of the switch looking shorter or recessed on the part for the 518 compared the 727.

[JonH]

Well now I have to ask. Why would you order a part for a car from 1974, when the transmission is clearly from a newer vehicle? You need the switch for the trans. you have, not the car you have.....

Now what was so hard about that...

[chargerdon]

Glad to hear it's working.
Any issue with the electrical harness connection?
The online pics seem to show the 3 pins coming out of the switch looking shorter or recessed on the part for the 518 compared the 727.

It went on fine, no difference that i can tell.. 

[chargerdon]

Well now I have to ask. Why would you order a part for a car from 1974, when the transmission is clearly from a newer vehicle? You need the switch for the trans. you have, not the car you have.....

Now what was so hard about that...

One i bought my switch from NAPA not Rock Auto for $16.99   NO SHIPPING NO WAITING...  and IF it didnt work, easy return.   I use rock auto a lot on more expensive light parts where the price difference is worthwile...otherwise i support my local business.