1979 F150 4x4 C6. Am needing to replace the transmission vacuum modulator. There is no color stripe on the old modulator but the rod looks like it may have some white paint on it. Does this mean the old modulator had a white stripe on it at one time? I know they are adjustable but since I have to buy one I would like to buy the correct one. The rod measures 1.707 in length. Thanks!

 

No, there are 4x pin sizes that I am aware of and 1.707 is long. 1.688 is the longest recommended rod.

1.601-1.611
1.634-1.644
1.650-1.660
1.666-1.677

The striping is based on the factory adjustment but generally are the same. All are push in except white.

Black is typically for light trucks
Green for Diesel trucks
Purple for low vacuum engines
White is a screw in modulator for all C4/C6 for 64?-72

Different rod lengths are designed to add adjust-ability if you have hit the modulator adjustment threshold.

Wire diameter is .125, with that said I use welding wire to fabricate my own pins. I have a "Old" kit that has an adjustable rod that collapses at the correct preload (.030) and then I cut the welding wire to size. Fine tuning can then commence but gives you a great start point.

 

Thanks F250. The rod definitely measures 1.707 with a digital caliper. It does not look homemade. Looks like I need to try to find a black modulator. Just wondering since the rod had a touch of white paint on it but the modulator is a push in style. Thanks.