AOD transmission Thread size????

[frost0100]

I am trying to place the order for the last few parts that will allow me to get my car running. I have a 89 351W hooked up to a freshly rebuilt AOD. Everything is done except my transmission lines. I have all the pieces with the exception of the fittings that go into the tranny. I can't seem to find a fitting to fit the thread in the transmission though. I have 1/8" -6AN braided lines coming out of the radiator and going back to the tranny. I tried 1/4" NPT adapter but it did not fit. It was close but no cigar.

Does anyone know what the thread size is for the AOD transmission? I did some research and found some to say it was a 1/4" but it just doesn't fit. Again, it is close - but does not work.

 

[frost0100]

I did find this information out, but cannot seem to locate this part in summit catalog or jegs.

1/4" NPSM

The fittings are actually 1/4" NPSM threads. These are straight pipe threads, 1/4" pipe (roughly .520" OD) with 18 threads per inch. Straight pipe threads don't provide a seal so the sealing comes from the shoulder on the fitting meeting the shoulder on the case. I have seen 1/4" NPT with teflon tape used here, but you would need to be extremely careful not to break the case because the tapered threads would act as a wedge trying to split the straight threaded hole in the case.

 

[woodsnake]

Maybe call Ford, or take it to a transmission shop??