Hi, My buddy as a 71 Maverick 302 & lately the car won't shift out of 1st when you put it in D. 2nd seems to work fine when you put it in 2, just like 1 works fine too by itself. The car sat for a year, but within that year we replaced the trans fluid, new filter & new vacuum modulator w/white stripe. I also replaced the Neutral Safety Switch, would that have anything to do with shifting? I have a new vac mod trans line also, & the fluid is at level & not burning at all or leaking, if anyone has any info, please let me know. Driving around in 2nd gear at 35 mph is crazy.
Im not an expert but the transmission sounds like it may be toast. I got a complete AOD setup for sale if that c4 is out of service. But get it fixed and ready for the Phoenix Maverick Meet in February. See the list of Az. members in the general forum for details.
Now that you mention governor stuck, I had remember I had a similar problem once. back when I had a c4 and didnt drive much, I took the car out one day and before I left I noticed I was low on fuid because my pan leaked a little. So I filled it up and went drove around the block. It still wouldnt shift, was acting like it was low on fluid. I checked it again and it was full. I was thinking maybe it was air in the trans. So I went and drove it, in first gear, and got on it pretty good a couple times. Eventually it started shifting and acting normal again. I thought it was air, but could be governor sticking.
I would put a half quart bottle of K&W Trans-X in it, if the fluid level is where it is supposed to be. If it is a little low, a whole quart would be fine. If it has a valve or something sticking in it from sitting, it will take care of it. I definately would try that before I started tearing it down. You can get the K&W Trans-X at Advance, Autozone OR Wal-Mart. K&W is my brand of choice, but others say Lucas and Seafoam are great for that kind of thing also. Did you make sure and replace the little spring and cup correctly, that came out on the top side of your old filter? It is important that it gets replaced properly.Just my 2 cents.
Check the connections to the vacuum modulator. Since it works manually there is no need to add anything to the transmission. I suspect that you are not getting a good vacuum signal at the modulator. Check the hoses and metal line for the modulator vacuum. There are no additives made that are compatible with type F fluid and "mechanic in a can" products usually do more harm than good over the long term. If the modulator or vacuum lines to it are not at fault then you can access the governor for cleaning without removal of the transmission. Let me know what you find and I will help you from there.
All kidding aside, I know you have good intent but some additive can ruin the paper composit friction material, some swell and soften the seals to the point they rupture or prevent operation of the clutches and others fill the transmission with a sealer material that can freeze up valves. All of then say they are OK for use in automatics - but none of them are "recommended for use in 66-83 Ford transmissions that use type "F" fluid. Having seen the results from adding all kinds of "fixes" (including brake fluid) over my 35+ years of rebuilding these transmissions I am adament about their use in the C4 and C5 transmissions. It can be very costly to replace clutch drums and clean out valve bodies after these products are run in out little C4s. If the correct fix had been used in the first place it would have been a lot cheaper to repair what was wrong.
Well thanks for all the cool replies. We dropped it off at a Mustang repair shop yesterday to fix a leaky new front windshield, just great! So I told them to put it on the lift & see if that little hose came off the vac mod-maybe the diaphram ruptured or something in the vac mod? If that is not it I'll check that governor out when I get it back home to see if it's stuck like the earlier post said. The car won't be back for a few days so I have to wait, I was bumbed because I put in a 3.40 8" traction lock a few months ago & am really want to test it out, but can't-going only in 2nd gear!!!
