Stuck in reverse...AGAIN?!?!

[Larrybrook]

1974 2.7 litre 911 This will be the second time stuck in two years.

The transmission was rebuilt about 10 years ago (by a reputable Porsche shop) during the restoration process. I probably have only put about 1000 kms on since then. All I did this time was pull out of the garage and park in the driveway...luckily I was able to push her back in and she's up on jack stands right now. Is it the gear oil? I used Motomaster Extreme Pressure SAE 85w-140. I will gladly change out the lubricant if that makes a difference. I have read that Swepco 201 or 212 is recommended. Anyone know where to purchase in London Ontario Canada? Is there another product more readily available around here? Is this really the problem? I am so hesitant to drive her anywhere now...

Thanks,
Larrybrook

[Bob Kontak]

OK - this link is based on John Walker's input. It is a minor job but DIY-able, although can be a stinker with electrical connection re-assembly..

Long story short, there is a pin underneath your reverse light switch on the transmission.

If you can remove the switch and push the pin in it may engage the reverse detent (I have no idea what a detent is, but I sound pretty knowledgeable) to allow it to come out of reverse. The other end of the pin, when in reverse, closes the switch to light up the white lights.

915 prob fixed. Big thanks to Pelican forums and John Walker!

[Larrybrook]

I have replaced the coupler and all the bushings in the shift linkage so that's not likely the culprit.

Also, I can get TUXON SYNGEAR 75W-90 or Castro 80W90 locally.

[Larrybrook]

I have done this once before, it was a little messy with the front end jacked way up and without draining the tranny; but I got it none the less.

This time I'll most likely drain the lubricant and push the pin back in and THEN replace with a superior product...assuming it'll help...

The thought of driving makes me nervous, I would hate to get stranded if this happens a THIRD time.

[Bob Kontak]

Originally Posted by Larrybrook

This time I'll most likely drain the lubricant and push the pin back in and THEN replace with a superior product...assuming it'll help...

I remember on my 915 when rebuilt, there is some kind of issue with parts not being as wide as original and this causes some disruption in engaging the reverse light - pin is too short, I think.

So from reading some posts, I went to Home Depot and bought a long high speed steel drill with a long shank that was the same dia. as the pin. I crafted it to the dimensions the post recommended.

I don't know if this would relate to the detent issue.

It may not be the quality, the original part may not be the best fit post rebuild.

Hope the trans guys will kick in for you and confirm or shut this idea down.

All the best.

[The cap'n]

Disconnect the linkage by removing the cone screw and try to move the transmission out of gear by moving the shaft (push on it). If it comes out of gear, you have a linkage adjustment issue.

The Cap'n

[Arne2]

Mine has stuck twice in that time also, but the only time it does it is when I'm messing with the coupler. In other words, when I get the coupler adjustment totally f'd up is when it gets stuck. Then I have to unstick it, and slow down and adjust the coupler correctly.

So my guess is that your coupler adjustment may not be as good as it should be. That, or your linkage bushings are worn and somewhat sloppy.

[1990C4S]

Originally Posted by The cap'n

Disconnect the linkage by removing the cone screw and try to move the transmission out of gear by moving the shaft (push on it). If it comes out of gear, you have a linkage adjustment issue.

The Cap'n

I would start here. Even going under the car and working the shift input shaft rotate the same direction you would for reverse, but reverse the push/pull.

So if reverse on tour tranny is counter-clockwise and push, you rotate the shaft ccw and pull it out.

[john walker's workshop]

the reputable shop likely missed the proper placement of one or both internal detents. (not the two on the side of the diff housing). when one shaft moves, a detent locks the other shaft. all you can do is keep pushing in the reverse light pin unless it's taken apart and fixed. swepco is not particularily good for the 901 and 915 friction style syncros. too slippery. use a 80/90 GL-5. i like kendall.

[Larrybrook]

That part was easy, use a big a$$ flat head screwdriver and the body of the car as a lever. Clickity click Barba trick. I drained the gear oil that was in there and will replace 80/90 GL-5 Kendall (or something similar). With the help of my Son I adjusted the shift linkage in hopes that "I won't get fooled again"... The lower part of the shift lever is now more vertical/plumb.

I'm feeling better about driving her since the picture below (from a fellow Pelicanite) of properly adjusted linkage shows a lot of "spline?" on the shaft:


Here's mine before adjustment:


If she get's stuck again, I will pull out the transmission and take it to the shop that did the re-build, see what they say.

I have my fingers crossed.

[Walt Fricke]

1) If you backed it out of your garage (using reverse), and it got stuck in reverse, did you find someone to sit in the car depressing the clutch while you pushed to get back in garage?

I'm glad you resolved it, but am trying to figure out how this happens, and particularly if it can happen even if detents are properly in place. There are one or two inside the transmission which can shift to the wrong place when you have the transmission all apart on an engine stand, and decide to reinstall parts with the case upside down (or at least not in the orientation which has gravity keep the detent on the proper side of the rod it serves to detain). I've made this mistake, but caught it before I had gotten too far in reassembly. I don't recall if the factory manual warns against this or not, but if you pay someone to do this work it is reasonable to expect he will know about this and not make the mistake.

So what exactly were the symptoms beside the fact that you couldn't engage any gear but reverse? Was the shift lever also stuck in reverse? No amount of pushing forward on it would let it move to neutral? Or could you get it into neutral, but couldn't engage any other gears? (not necessarily a bad thing, because one common problem is a transmission locked (luckily, while the car is pretty much stopped) into both reverse and some other gear (which means you can't even drive it backward).

2) I am doubtful that the transmission oil had anything to do with this.

[Larrybrook]

Yes, I backed the car out of the garage, I'm sure I used the parking break, don't recall if I left it in reverse while parked...but several hours later when I tried to return to a clean garage...the car would stall if you let the clutch out. (Note to self: "never clean the garage")

Luckily the neighbour and his wife were home (my family was nowhere to be found), we backed the car all the way to the street due to the incline and pushed the car while she steered with the clutch down...

..Luckily the neighbour and his wife (and her mom) were home, we backed the car all the way to the street due to the incline and pushed the car while grandma steered with the clutch down...it was a little steep for just the two guys. (Thanked them the Canadian way, with cold beer and coolers...nice eh?)

Symptoms: engine runs with clutch depressed, cant get tranny out of reverse. shift lever moves but wont go into another gear, or it's in both...not sure. I admit I never tried driving it backward. hopefully I will never have to try again.

Good excuse to change the engine oil while up on jacks, and I have new gear oil as well (80/90 GL-5).

She's back on terra firma, but I got caught up in the Germany v Brazil world cup game...test drive tomorrow.

[Walt Fricke]

With careful adjustment of the shift linkage, you may have solved things, at least for the foreseeable future.

When you push the shift lever over to the right to shift into reverse (or 5th), a finger on the main shift rod (the one the coupler attaches to) moves down (or maybe up) and engages a slot milled across the rod which has the 5/R shift fork attached to it. Because it is dropped down into a slot, moving the shift lever back or forward will now move that rod one way or the other.

Over time, the edges of the slot can get rounded, as can the edges of the finger. As a result of this, if the finger doesn't move as far as it can into the slot, the bevels can push it up as you try to move things back and forth. If you are in reverse, and things are loose, you might have pulled the finger out of the slot while the rod was still in reverse. If by chance you started to pull out of reverse before the clutch was entirely released, this calls for more pressure on the rod to accomplish, making it easier for the finger to be pulled out of the slot from fore or aft motion.

So now the shift lever is in neutral, and can be moved over to the 3/4 or 1/2 position. But I think the detents John Walker referred to are set up so that you can't move the 3/4 or 1/2 rods deeper in the transmission if the 5/R rod is not in the neutral position (i.e., neither of those is engaged). This prevents engaging one of those gears, which is a good thing, because if you engage two gears at once, you can't move the car! Doesn't matter if the clutch is depressed, the transmission is locked, which means the ring and pinion, and thus the wheels, can't move!

But when you move the lever back to what should be 5/R, the finger just sits on top of a completely round rod, so it has no purchase to move it forward or backward anyway.

When you did the reverse switch pin trick, you pushed the 5/R rod backward to its normal neutral position. Now everything is lined up. Luckily, it seems we never have this problem shifting out of 5th, because there is no way to pull, rather than push, on that rod with the transmission in the car.

Careful adjustment of the coupler, biasing it a bit toward pushing the finger deeper into that slot, might get it below any bevels. Same with being sure that the bushings in that connector are good. They are designed to be loose in the fore and aft direction, which doesn't affect any of this. But it is their rotational tightness which counts.

That's my pop diagnosis.

If you could push the car backward, you could have driven it backward under my take on this, so I don't know how to explain the stalling (other than just normal messing things up and stalling).

[Bill Jennings]

A couple of years ago when removing my car from the container my car was imported in, the port driver managed to get my car stuck in two gears. A chat (interrogation) to her revealed she had gone from reverse to 1st gear while the car was still rolling backward. The symptom was car would stall as soon as you started to let the clutch out even with high revs, could move the gearlever to different positions but without selecting anything different and could not drive the car in any direction. We bounced the car onto the trailer for the 180 km trip home. Once home I found it was no longer stuck in gear and had fixed itself. I'm assuming the jarring of an unsprung trailer unstuck the problem. Was very disapointed my new to me car had what I thought was a stuffed gearbox. Later after reading here about linkage issues I renewed the coupler and lever bushings and managed to get it stuck in two gears again when trying to adjust the linkage. I was able to get it unstuck by moving the gearlever around while letting the clutch out with the engine running.
I am very careful to ensure I am at a full stop when changing from reverse to 1st and have not had a problem since.
Like the OP I was very fearful that the car could get stuck at anytime until I renewed all the linkage and found a way to free it whilst sitting in the car.

Cheers
Bill

[CatsEyes]

The whole linkage adjustment process can be bewildering if you don't have a firm point of reference. Just a tiny mis-adjustment of the coupler too far to the left or right, or up or down, can have you with all gears one minute, and then mysteriously missing one or more a few minutes later. I've left the house OK, but had to limp back home in third, because first and second (or reverse) disappeared while driving, after a mis-adjustment.

I found that Bob Tindel's procedure worked much better for me than the factory procedure. Basically, you load the gear lever full to one side, and the coupler to the other, and tighten in neutral.

Pelican Technical Article: 911 Shifting Improvements

If that's all the problem really is...

[Larrybrook]

I did use this Pelican Technical Article: 911 Shifting Improvements, and I have replaced all the bushings including the coupler. New gear oil, new engine oil...just gotta find a few minutes to take her for a spin.

wish me luck!

[Larrybrook]

She runs like a jewelled watch, solid in all gears. it did pop out of 5th gear when I was on her heavy and I popped the clutch, but normal driving was perfect! mroe test drivs required...

[azzarule]

Just got to say thanks for this thread, saved our bacon, we got stuck in reverse after Hubby played with the coupler adjustment, but followed this thread advice and voila. Love your work Pelican gurus.