|
Stuck in Reverse with a Twist
I spent Friday reading any "stuck in reverse/gear" thread I could find. I got my '79 915 in this position trying to back out of the garage on Friday morning.
In many of the threads drivers mentioned recent work on either the coupler/bushings or the 915 internals themselves. In my case I have not made changes to either but had symptoms that caused me to suspect the bushings and order a new set. In the mean time my factory short shift selector rod has begun to rotate (which I read is a characteristic failure). I now have the classic regret for not addressing both of these sooner. The twist in my case is that while others in this situation have mentioned that they seemed to be able to engage other gears 1-5 fairly easily I can say that effort to get into the 1-2 plane in my case seems pronounced and I can't see much or any coupler rotation when moving from R to 1. Is the coupler motion (or lack thereof) indicative of simply being stuck in reverse, maladjustment or something worse? Am I right to assume that I need to get into neutral to remove, reinstall an adjust the coupler? If so should I assume pushing the reverse switch pin back into the case is the right method? Thanks in advance for your collected wisdom. |
What I found in my recent experience was that the coupler would move as normal. I could select any of the gears using it, disconnected from the shifter linkage.
My fix was to remove the reverse light switch and push the crazy little pin back into it's home. Once I felt it disengage the detent, the wheels moved freely. Once your car is safely on jack stands/lift, try moving the rear wheels both in the same direction. If it's the detent, the wheels will not turn at all. Depending on if you have limited slip, they may turn in opposite direction to one another. This is how I confirmed my problem(besides the car jumpstarting itself and driving up the tow truck but that's another post.) BTW-I had not done anywork recently on my shifter linkage or bushings although I did notice it was difficult to select reverse once in a while. |
When mine was stuck, I did not have full range of side to side motion. First and second was difficult if not impossible. I'd recommend getting it too where you have only reverse with the lever as close to the neutral position as possible. Then try to push the rod under the reverse switch back into place.
http://forums.pelicanparts.com/porsche-911-technical-forum/659567-915-prob-fixed-big-thanks-pelican-forums-john-walker.html |
Thanks for the quick thoughts. I've definitely read that thanks to Pelican & JW thread. I think I'll try the reverse pin tomorrow.
In case I need an excuse to drain the 915, how long does gear oil last in a street rod? Don't worry I won't ask what to put in it if I drain it. |
Funny how projects of passion/recreation get put on the back burner...
So I finally go to do this today and I find that the initial symptoms seemed to have evolved. When this problem first occurred I found I could only reliably select reverse. I validated this by backing out of the garage a tad but pushed the car in after reconsidering driving to the office in reverse. Now though I still have the same motion available (which is to say 5 R plane biased) I can't seem to only select reverse. Trying to back up now the car just stalls as it did when I tried to select forward gears before. Is there anything else a novice but diligent enthusiast should do to diagnose/remedy this at home? |
did you try to push the pin in? you seem to be aware that is a likely solution but reluctant to do it. I can tell you when I had a similar problem (stuck in R plus problems getting into lower fwd. gears no matter how coupler was adjusted) it was a broken 1-2 slider.
|
I should clarify that I was trying to back it onto ramps to push the pin in but since I was unable to get it on the ramps and the symptoms seemed to change I did not proceed.
My assumption was that if it is stuck in reverse I could use reverse and pushing the pin in will put me in neutral. If I can't use reverse at all I'm wondering if I have another issue that pushing the pin in will not fix since my understanding was pushing the pin in just disengages reverse. |
Sounds like you are either overthinking this or need some outside help.
|
If anyone has a suggestion I can try to get only reverse selected I would appreciate your thoughts.
Likewise if I am over thinking this and pushing the reverse pin in would be helpful even if I have more than reverse selected that would be helpful to know too. One of the other stuck in reverse threads had an owner, apparently luckier than me, who was able to fiddle with shifting out of reverse and successfully got into neutral. I had tried to do the same by selecting reverse and gently shifting back to neutral repeatedly (maybe 8 times). I wonder if this has anything to do with my current problem which seems to be that I am always in two gears instead of sometimes being only in reverse. Thanks in advance for any thoughts, |
Every thread is better with photos: :)
http://forums.pelicanparts.com/uploa...1355626812.jpg Please help me help the narrow blau hotrod get back to what it loves to do. |
If you can get it to where it reverse works (i.e. not two gears, reverse only) with the lever somewhere in the vicinity of neutral, that will likely be the time to try to push the rod in. That's what worked for me.
|
Thanks Arne. I'll give that a shot.
|
If I am stuck in gear should I be able to rotate the rear tires at all? Mine will rotate with some resistance and spin in opposite directions (915 has LSD).
|
Quote:
|
Oh great... Can/should this behavior change with damage or other circumstances?
Didn't try firing it up now that all four tires are off the ground but previously it stalled without budging whenever I let the clutch out. So I was shocked I could rotate the tires by hand at all. Weather has been such that I've not been missing much driving so far but this is starting to look like a more painful repair. Thanks for your thoughts. |
If you are sure you have a LSD, and your axles are spinning in opposite directions, then the differential is not functioning properly (ie:the clutch plates are worn out). If you search "limited slip" you will find quite a bit of detailed information on this.
I don't think that this would have anything to do with your other problem but do not know for certain. |
Stall when clutch let out = stuck in 2 gears.
Push the #$#$% backup light pin in. You won't lose enough oil to worry about. The diff issue = LSD worn out. Not that much of a problem as things go. Car will work fine without it. |
When I removed the switch I could tell that there was a pin there but already seemed quite depressed. FWIW the reverse lights where not active before I removed the switch. They had been at another point in this process so perhaps I need to try to shift back into reverse and try again?
For those looking for the switch the below picture is taken with the switch removed camera facing toward the rear of the car from just in front of the transmission support. http://forums.pelicanparts.com/uploa...1358129971.jpg Mine did not have the boot that is on the exploded parts diagram but YMMV. I lost about a third of a quart being slow to decide to reinstall the switch hand tight while I consider next steps. Does tired Swepco look this cheerfully bright blue? Either way I am wondering if the next step is draining the trans and opening the bottom inspection panel. If I see something bad (eg. chunks of metal) when I drain the trans or open the panel can I still get the car onto a flat bed with an empty 915 by holding the clutch in? I want to push further into trying to fix this but I don't want to wander into a dead end of my own creation. Thanks again for all the input. |
you seem to have a pathological fear of trying to push the pin in. if you think it is already pushed in, confirm that by pushing it with a punch and mallet. if it doesn't move that means it was already in.
|
Perhaps a fair judgement...
I am scared to damage my favorite possession. Trying to balance that with the ideal of learning to take care of it myself as much as is reasonable. Being a perfectionist about something you have no experience in may not be a healthy attitude. ;) Genuinely I assumed it was all the way in because (as you can somewhat make out in the photo) the pin is not visible. I could feel the end of it with a finger but it wasn't actuating the switch. How far back can it reasonably be driven? It is quite a bit higher than the floor of the car so I would have to find a way to use the punch on about a 30 degree angle... |
Some understanding may help here. Reverse and 5th are engaged by a rod which has a finger sticking off to one side. In the main shift rod - the one which sticks into the passenger compartment - there is a slot. When the main shift rod is rotated to the 5th/reverse position, the finger engages the slot. At that point, moving the main rod forward or backward (and remember that the shift lever console reverses the direction of movement of the shift knob) moves this secondary rod. The secondary rod has a fork on it, which moves a sliding piece. This either engages the synchro and teeth of 5th when moved to the rear of the car/transmission, or physically moves gear teeth into mesh with the reverse gear.
What happens if a car is in reverse, and the driver yanks it out of reverse? Well, usually nothing bad, but it is possible for the finger to skip out of its slot before reverse is disengaged. If another gear is now engaged (1st, for instance), you are in two gears at once and going nowhere. Putting a transmission into two gears at once during a rebuild is one way of locking the shafts so that nuts can be tightened. Nothing much can turn at that point. The backup light switch is a lightly spring loaded pin. Parts of the reverse gear system physically pusn on the end of this pin, and it closes a circuit in the switch, etc. But this means that the pin, if it gets shoved hard enough, can push the short shaft, and thus disengage reverse if pushed far enough. This is not the only way troubles can happen in transmissions. But it is relatively common, as such woes go. Which is why you are being urged to try it - hard. You won't damage anything more than perhaps it already has been damaged, and you might undo the problem. The slot in the main shift rod should have nice square, sharp edges. Over time, the edges can get worn, making this kind of thing more likely. You might think, as I often have, that if a guy just put the car back into the reverse position on the shift lever end of things, the finger would plop back down into its slot, and all would be well again. As it can be if the backup light pin trick works. Doesn't seem to be the case, for reasons I don't understand. it is much harder to get the tranny into any two gears when none involve reverse. Unless improperly assembled, there is a clever ball and spring interlock system such that when the 1/2 secondary shaft is in either of its engaged positions, the 3/4 shaft cannot move at all. Anv vice versa. However, if all else fails, and you decide to look farther before calling the flatbed truck to take the car to a shop, pulling the "inspection" plate (really the holder of the dongle fulcrum fork) will give you a view of sorts of the innards. You can see where the dongle end is, which of the two shift selectors is or is not engaged, and have a chance, if one of them is engaged, of disengaging it. As you know, the shift rod has three rotational positions: 1/2, 3/4, and 5/R. In either of the first two, the ball end of the dongle (the thing the shift rod moves inside the main tranny housing, which you are staring at with the plate removed) should be in one of the secondary shift rod engagement slots, depending. When in the 5/R rotation, it has moved free of both of these engagement slots, and should be able to be freely rotated up and down through them. So it will be quite obvious if something is amiss in there. Good luck |
If you are only locked into one gear, depressing the clutch will allow the car to be pushed or winched. If locked into two, no. But the flatbed folks ought to be able to dolly it up. They usually have dealt with all kinds of problems.
|
Walt-
Thank you for your detailed and enlightening posts. When I first started to experience the "stuck in two gears" symptoms I had already managed to back the car part way out of the garage. The temporary fix was to push it back in with the clutch depressed. If it is truly not possible to push the car with the "stuck in two gears" problem then perhaps I have another issue. I am thinking the next step is to drain it, filter the oil for evidence and go from there. Assuming no obvious damage I'd open the bottom plate. Could a loose fork be causing my symptoms? My question about pushing/towing an empty 915 was assuming a worst case scenario I'd not want to fill it again just to flatbed the car. |
Quote:
|
Sounds like you are only stuck in one gear, which is better than being stuck in two.
And that the one gear stuck is reverse. Hence the exhortations about the pin. Is your shift lever in neutral, or thereabouts? |
If I was only stuck in reverse then it should not stall when I let the clutch out so there must be something else going on.
I have definitely tried pushing on the pin (though I see now I did not make that explicitly clear). I have not hit it with a hammer yet but I gather I don't have to worry about it being delicate. Shift lever is in neutral near reverse. Trying to shift into any of the gears at this point has a large amount of resistance. |
what are you pushing it with, your finger? unless you're Dr. No, that won't work. you don't need a sledgehammer, but you need to give it a solid rap (like with a plastic face hammer and punch).
|
Some progress I hope!
Fiddled with the linkage shifting into and slowly back out of reverse seemed to leave the pin in a more protruding position. Whacked it with a small hammer using a long bolt as a punch. Buttoned it back up (even optimistically reattached the switch wiring). Against my better judgement I fired it up on the jack stands because I wanted to be able to see rotation no matter what gear I was in (assuming I was in any one). Eased the clutch out and spinning rear tires! I the shifter appears to be in neutral can I assume pushing the pin back put me in fifth? Or is that precisely impossible since whatever gear I'm in now can't be the opposite pair on the slider for reverse (5th). Thanks all for the mechanical support group! |
Up on stands, RPMs just a bit above idle, you should be able to see if tires are rotating forward or backward. And 5th would rotate rather fast, even at low RPMs, vs a lower gear.
You might try moving the shifter into 5th (I assume you have pulled the rubber boot around the shifter up so you can see what is going on there, as you want the hook on the shift lever over the tab on the shift tower to be sure you are in 5th). Can we assume you have pulled back the rear passenger seat area tunnel upholstry, and removed the cover plate, so you can look at the shift coupler? The easiest thing to get a bit loose and go wrong with that coupler is for it to start sliding a bit where it attaches to the shaft coming to it from the shift lever. You put a whole lot more force on that clamped joint moving the lever forward and backward than side to side - you have to overcome synchro forces and so on, not just moving internal levers side to side. If pulling extra hard moved this joint backward, that might explain being in 5th but seeming to be in neutral (other than the fact that the lever would not feel like in neutral, just positioned as if it were). The movement you saw of the pin sounds like pretty good evidence that you were able to move the 5/R shift fork rod. I don't know if the backup switch pin is long enough to force things into 5th - maybe it is. Getting neutral is usually enough for victory. |
Shift boot is pulled up and yes the panel above the coupler is off. When this was originally problematic I expected to see that the coupler bushings in pieces as others have reported. Coupler bushings are intact but I will replace them, the cup and rod bushing as soon as I square this issue away. I don't think the coupler is loose but I will double check that.
It seems that what would normally be expected is that pushing the pin in would result in my being in neutral. Is there something else that I should do at this point to try to get into neutral? |
If you conclude from watching how the wheels rotate you are most likely in 5th, try to move the shift lever there to see if it will re-engage.
|
Earlier input from Walt that may help others:
Quote:
Quote:
|
First and foremost thanks to all for the help and advice. I drove the car to work today to celebrate victory.
In the end fiddling a bit with the shift lever (just within the play of the neutral area) seemed to drop the transmission out of the remaining forward gear it was engaged in. Once the car was no longer stuck in any gear I did note that both rear wheels spin in the same direction when I rotate them by hand. Perhaps there is still some life in my LSD after all. Next steps will be to replace all shift linkage bushings, change gear oil and enjoy. |
When you drain the gear oil remove the cover on the bottom and check that the shift fork is bolted tight to the cover.
http://forums.pelicanparts.com/uploa...1358543922.jpg |
| All times are GMT -8. The time now is 10:07 PM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website