|Almost the oldest RV in the park until this one showed up!!|
|An Astro Van Allegro from 1986! Great couple that is traveling in this one. They have a Harley as a toad!|
The problem?? Well the RV has a TurboHydromatic (TH400) three-speed transmission and there are a couple of things that happen to these over time. One is the vacuum modulator can go, stopping it from shifting. Simple part to replace if you have it. I'm keeping spares in the RV. The other possible (and more likely) issue is with the little plastic gear on the end of the governor that controls shifting. This part is purposely made weak to prevent damage to the tranny should any abuse take place. The part gets used up and saves other more valuable bits inside.
A lesson on the TH 400 GM Transmission:
|A shot of a very clean and new TH400 (I am so jealous!) the white thingy with the red nipple is the modulator (or as Marvin the Martian would say, the PU36 Space Mod-u-la-tor!) Near the back is the governor cover plate on the same side.|
|This is a picture showing what happens to that gear over time. Once it looks like this it's toast and you wont get out of first gear. The kit costs about $8 online.|
|A kit you can buy off Amazon for about $7 to fix what is likely the main suspect in your no-shift issue.|
|This is what your governor looks like if its in working order. These can be had for about $70.|
|A red stripe vacuum modulator that controls shifting. Sometimes these go or the vacuum line gets brittle. Cheap at about $16 so it's worth just getting if you're not sure.|
More later once we get there and see what's up! Oh, the joy of owning a vintage RV!
UPDATE! Got to Camping World and did the gear swap. The old gear was completely worn down! The RV is safe at home now and awaiting a new transmission filter and oil change.
Thanks for reading!!