Transmission / Overdrive: Can not shift to reverse

[tim333]

57 Commander 259V8 Manual trans woOD: Runs fine, shifts smoothly into overdrive. When stopped I cannot shift into reverse. In neutral with clutch depressed or released, car will not move (Engine running or not). I can restart and drive in all forward gears normally. This happened a few weeks ago, had to jack up rear end and pull car back with the floor jack. I noticed the rear wheels starting to move forward as the jack raised them off the ground. Problem went away after driving forward then but today it went go into reverse at all.

[jclary]

Perhaps someone with better expertise will chime in, but I'll take a stab at your problem. Overdrive transmissions have a "reverse lock-out" feature. Through the years, I have experienced a similar problem you describe. For some unknown reason to me, I have had a problem where my overdrive did not automatically "disengage" as it is supposed to when slowing to a stop. You'll know when this happens, because if you try to pull away from a stop in first gear with the overdrive engaged...it is similar to attempting to start off in second gear. If you pull into a parking place and the car is "hung up" in overdrive, the reverse lockout will keep you from being able to engage reverse. When that happens, try pulling the overdrive cable out. That should allow you to shift in reverse.

It has happened to me only a couple of times. Manually operating the cable has cured it and I've never had to do anything else to my car. Hopefully, you'll be as lucky.

[tim333]

I can't pull out the overdrive lever either, won't budge.

[jclary]

Next question...does your "kick-down" (passing gear) work? Have you jacked the rear wheels off the ground and attempted to manipulate the gears off the ground? How, bout pulling the cable while in neutral? Is your cable seized? Perhaps you'll need to go under, disconnect the cable, and move the lever with pliers?

Just trying to help...

[tim333]

Haven't done any troubleshooting yet, will over the weekend.

[RadioRoy]

The governor might be shorted in the "on" position. If you turn off the ignition, can you put the car into reverse?

[tim333]

With engine and ignition off I still cannot shift into reverse and car will not roll with lever in neutral or clutch depressed.

[TWChamp]

From under the car, move both tranny levers to be sure each is truly in neutral, then try to roll the car and try to pull the overdrive lever. Also try to shift to reverse.

[AC0J]

It wont roll with the clutch depressed? You got more than a linkage problem i would guess.

ETA; sounds like the tranny is locked up, the diff is locked up, or a brake is locked up.

[tim333]

AC0J....I can start the car and drive normally forward in all gears including overdrive. I just can't shift into reverse.

[AC0J]

OK, I read "it wouldn't ROLL" even with the clutch depressed.
That being the case, I would concur with twchamp as described earlier.

[gordr]

Sounds like something is blocking the rearward motion of the overdrive shift rail. Its purpose is not to lock you out of reverse when overdrive is enabled; rather the converse, to disable overdrive when reverse is selected. In order to do that, the shift has to be free to move backward. I am thinking you may have a broken overdrive pawl. The pawl is a slug of hard steel about 1" square. The stem of the solenoid slots into the end of it. The pawl has a notch in one side that the OD shift rail passes through. The rail has a narrow neck on it, and when the rail forward, the narrow neck aligns with the notch on the pawl, giving the pawl freedom to move inward when pushed by the solenoid. When the rail is pushed (or pulled, by the manual lockout) back, its larger diameter aligns with the notch in the pawl, and prevents the pawl from moving inward, even if the solenoid were powered up.

I'd suggest, #1, get the car on a hoist, and remove the solenoid, and see if the pawl can be moved by putting a screwdriver into its slot, twisting to get a grip, and then push or pull. You should be able to get about a half-inch of in-out travel. If the slot seems too broad, and you can't grip it by twisting a screwdriver in it, then the pawl may be split. If you can move the pawl, try working the manual lockout (after disconnecting the cable). If the pawl is fully out, you should be able to move the lockout lever forward, and once it is forward, it should then be impossible to move the pawl in more than a smidgen.

I suspect, ultimately, you will have to remove the transmission and tear it down. Are you sure that it is going into overdrive? You should have four forward gears, first, second, third, and third overdrive, so you should experience 3 shifts, 1-2, 2-3, 3-OD. Yes, you can get second overdrive, too, which makes a total of five forward speeds, but you have to go pretty fast in second to get there. If you know the overdrive is working normally, then chances are it will be a pretty easy fix, either the pawl, or shift rail, or both.

I suppose the sun gear could be stuck on the mainshaft, too. Do check the lube level when you get under there; both in the main case of the transmission and in the OD housing too. If lube is very low, or absent altogether, you just might get lucky, and everything might come good if you refill it, and drive for few miles. If that happens, go buy a Powerball ticket while you are hot.

[tim333]

Correction!! It DOES roll forward so it truly is in neutral. Reverse is locked out....stuck OD solenoid?

[gordr]

The overdrive contains a one-way clutch. With the cable pushed in, the car is free to roll forward in neutral or any forward gear. That is why you are advised to place shift lever in reverse when parking, so the car won't roll. Previous suggestion stands. Solenoid might be stuck, more likely the part it drives. Does the overdrive in fact shift when driving in forward gears? If so, solenoid cannot be stuck.

[tim333]

I was probing for voltage at the OD relay fuse....when I touched wire #4 position the solenoid clicked. It now shifts to reverse. Troubleshooting chart says disconnect wire #4 and if the solenoid clicks replace the relay. I guess my probing was the same as disconnecting the wire. There is 12v at all terminals of the relay with the ignition off...is that correct?