Another newbie 915 shifting question--first gear

[mbintx]

I've had my '74 for 2 months now. Whe I first got it, I had some issues finding third gear, but decided it was user error. Now that I have figured out that the 2-3 shift requires a deliberate little "jog" instead of a straight diagonal movement, I rarely have trouble finding third. Yay.
However, first gear is a different issue. When coming to a compete stop at a light, for example, trying to engage first gear is a 50/50 proposition. It will either slide in like butter, or it will refuse to engage. If it doesn't engage on the first attempt, I have to either disengage the clutch and try again, or sometimes I'll put it in second gear and then try to slide it back into first. What I haven't found is a quick and reliable Plan B if first gear is being stubborn.
There is no grinding, and all other upshifts ans downshifts are trouble free. Could this just be an adjustment/alignment issue?

[Bill Douglas]

A good first thing to try is to change the gearbox oil. This might fix the 2nd to 1st thing. THe other business may be sorted with a new coupler and even new engine and gearbox mounts/sport mounts. Good luck, and I don't think it's a gearbox itself problem.

[toddu]

Yes, new bushings are probably in order (all shift rod related, not expensive), and a linkage adjustment. I find shifting into first is easier while almost stopped, but still approaching stopped. So like the last few feet prior to stop.

Todd

[Reiver]

Have you tried double clutching? That can assist you if the synchros/dog teeth worn.

[puddy]

Bushing can make a huge difference to the feel of the shifter. I'd start with that.

From my experience the 915 doesn't want to go into 1st gear unless I'm almost stopped. I'll also double clutch to help mine shift into gear easier.

[zedsn]

I have the same issue with my 1977 915 box. I believe that the many miles on my box has not helped the situation. I have done all the parts changes to try to cure this including a wevo shifter to no avail. I am afraid that you will just have to live with this unless you want to drop the box and have it rebuilt.

[jlex]

If you're trying to engage 1st while moving: DON'T. Is hard on the synchros. When I had the '85, I made sure I was at a complete stop before going to 1st....

[javadog]

It's an issue with shifting technique. The easiest way to put any gearbox into first is to do this: when you are slowing to a stop and approaching walking speed, shift into neutral, release the clutch, then press the clutch again and shift into first. Done right, at the right speed, it will go into first gear almost effortlessly.

If you have old transmission fluid, or the wrong fluid, changing it can be beneficial. Making sure the bushings are all in good shape takes no time and it's always a good idea to replace worn parts. However, neither of these things is a substitute for learning the right techniques and becoming aware of what feedback you get from things like this.

JR

[Drisump]

My car has, and continues to be straight forward to put in first while moving slowly. I have a long, rough, steep driveway that is best handled in first. I approach the driveway, slow to climbing speed, VERY lightly blip the throttle and she slips into first perfectly every time. Very occasionally she is a bit of APITA getting her in while at a dead stop but going into second before slipping into first always does the trick. Cheers

[fizeus]

All the previous suggestion are correct.
I also vote for a bushing problem or a wrong/worn transmission fluid.
If possible I'll add to check for idle speed... it should be between 850 and 950 rpms or you will suffer engaging problem.
Always engage 1st after a complete stop with javadog's tecnique if your bushing and transmission fluid are good (use swepco 201!!!) you will not have anymore shifting problems.
Keep in mind 915 gearbox it's not a modern gearbox and has to be treated with respect.

[javadog]

My technique is to shift it into first before a complete stop, not after it...

JR

[gomezoneill]

How many miles on the car/transmission? Most likely the dog teeth and/or syncros are worn probably both.

[mderienzo]

I have this same issue after replacing all bushings, mounts, and fresh Kendall fluid. I'm quite sure this is related to mileage and wear on my trans.

My technique is to shift into first just as the car comes to a stop if I know I'm going to get going again right away. If I am going to wait a while like at a traffic light, I leave the car in neutral, clutch out. When I'm ready to go, I put the clutch in, briefly touch the shift lever to 4th gear (just a quick 'click' on 4th, not into the gear) and then it slides right into first. I got this hint from an Alfa Romeo friend of mine (Porsche guy here too) since old Alfas use "Porsche-type" syncros and this was a common problem with them too.

Either way its a timing thing that works 90% of the time and rewarding once mastered :-)

Mark

[mbintx]

Thanks for all of the feedback. I can add that the previous owner was meticulous and had the car serviced at one of the best air-cooled shops in Texas. I'll verify, but pretty sure all fluids are recent.

I'll try some of the suggested techniques to see if i can improve first gear engagement.

[zedsn]

I changed the gear oil in mine and found a dog tooth on the magnetic plug and there was no change to first gear shifting with new gear oil.

[Walt Fricke]

Zed - er, did you open the transmission up to replace the engagement tooth part which had lost a tooth?

The shifting into 1st problem is a bit irritating, but not all that uncommon. My humble Suzuki Grand Vitara sometimes doesn't want to go into reverse, but putting it in 5th when that happens, then back to reverse, usually works.

The 1st gear synchro band and the gear's and operating sleeve's engagement teeth ought not to wear significantly. First off, the greatest wear usually is in 3d, where we all like to hurry the 2d to 3d upshift. 2d would be next, for the same reason. Other than at the track, most driving does not involve hurried downshifts, and those at modest RPMs.

At some point Porsche changed the shape of the engagement teeth for 1st gear, I guess on the theory that while for gears which see upshifts as well as downshifts symmetrical teeth are what you want, for a gear which doesn't see upshifts you can make the teeth asymmetrical, which they did (note these are the teeth engaged when shifting, as the gears themselves are always in (constant) mesh.)

Anyway, the touch (or engage) 2d - or 4th, or any other gear) approach if it doesn't want to go into 1st usually works. I think that if the gears aren't moving (which is pretty much the case when the car is stopped and the clutch is in for a while), sometimes it is as if the points on the gear's engagement teeth are hitting exactly on the ends of the teeth on the operating sleeve.

Here is a wear hypothesis, though. The operating sleeves move back and forth on the Y shaped spyder pieces, which themselves are splined to their shaft. If wear on the operating sleeve grooves, or the surfaces and sides of the spyders, or both, get to some point, the sleeve can sort of cock and be more resistant to moving. Not sure why this should affect 1st more than other gears, especially 2d and 3d, though, as I think they see more shift action.

Whatever you do, don't get so PO'd that you try brute force. I succumbed to that once, with the result that I drove home with 3d and 4th only, as I had actually bent one of the forged pieces inside the transmission by wedging the ball end of one of the shifter parts between the two internal receivers on the two shift rods.

[zedsn]

No I did not open the box and believe the tooth is actually from second gear and not first. I believe first is just kinda wearing out from higher miles. I do have to double clutch second or it will grind. I am getting pretty good about double clutching though and I do realize that I am on borrowed time and could have a catrastophy on my hands with second completely failing and locking up. I just got my 911 on the road finally this Spring and the car was basically new to me then.

[javadog]

There's no way is continue to drive a 911 that had any broken parts in the transmission. Lots of expensive things in there and I'd hate to tear them up.

JR

[GH85Carrera]

Originally Posted by javadog

My technique is to shift it into first before a complete stop, not after it...

JR

Same here. And that means at one or two MPH, NOT 10 or 15.

That does not help at a red light however. I don't want to sit at a red light with the clutch depressed. One thing for sure is don't just push harder to get it into first. If it does not want to go into first after sitting at a light, shift into second gear first.

All of that is assuming the gear oil is fresh, and the bushings in good order.

[JackMan]

Here's a tip. While at a stop light or sign, give slight pressure into first gear with the clutch in. If you sense the gear isn't going to get selected, blip the engine, just a wee bit to 3,000 rpm. That rattles things around in the gear, box, linkeage, etc. and the gear may or may not select.

This is not a fix but a coping mechanism until you can adjust the linkage and replace the bushings. The Wevo precision shift joint is a wonderful add on to any 911 shifting mechanisms. Their shifters are out of this world.