Scenario: Going to work, stopped at a red light: light turns green and I shift to 1st and the car starts moving forward "like normal" for just a couple feet and the shifter pops back into neutral. Had to pull to the side of road, did the usual check to confirm shifter in neutral and shifted into 1st and drove off. Had not experienced this before.

Question: is this an indication of potential trans problems brewing, any recommendations on what I should do next?

Thank you

 

Since it's done it only once, I might suspect the shifter was not fully in first gear position. I would suggest monitoring it to see if it happens again.

 

If your car has an aftermarket shifter, and it has stops, and they're not adjusted fully 'out', if you will, it can cause your shifter to be not all the way in gear. This will pop the gear out as described. The TR3650 has internal stops, so any additional stops on the shifter are absolutely not needed and in fact can be detrimental. If the thing pops out of gear it can damage the gear or the synchros.

You can possibly also get this effect if the trans mount or the motor mounts are bad, thereby causing the transmission to shift under torque load, and since the shifter is not directly mounted to the transmission, there can be a binding that might potentially cause the shifter to pull the thing out of gear. So check your mounts, just in case. Remote shifters and three rail internals are... yeah. Also, check the bushings of the shifter and mounts. If they're bad, replace them.

If all that's good, you probably just didn't have it fully engaged. I did that once before, just didn't have it fully in, took off, popped right out. Happens. Be firm, and don't worry about 'over-engaging', the internal stops won't let you do that. Shove it in there good.

If the problem persists, there may be a bad shift fork, and the transmission will have to be rebuilt/repaired. One hopes that's not the case.

Also, go swap out your transmission fluid. Over the years, metal particulates add up in that fluid, and you need to swap it. Mobil 1 ATF seems to be the best I've tried, but Royal Purple Synchomax or GM/Pennzoil Synchomesh are also good stuff. I'm sure others will chime in about this or that.

Hope that helps, and welcome to the forums!

 

Welcome to the forums. As for your trans issues are concerned, I would follow the advice from ZGrand and Houtex's posts and if their recommendations don't help in resolving your issues? then I'd consider having your trans looked at by a shop.

 

Thank you forum! awesome to see such a helpful community of Mustang enthusiasts