M56H Manual not shifting into 1st/2nd, rest of gears are fine

[DWBF1]

Any ideas on this?

Just did a manual swap and I've run into a bit of a problem.

Car will shift into 3rd, 4th, 5th, and R without an issue. It will shift into 1st and 2nd gears too, but there is not a "click" and those gears do not engage. The car will roll forward when it's in 3rd and I let off the clutch. No forward movement in 1st or 2nd. It is not physically difficult to get the gear selector into 1st or 2nd.

I noticed the following:

In first gear, the shifter cable is fully retracted. It is short of the pin by about 1/4". I can put it on the pin by extending the cable, shown in the first picture



Similarly in second gear, the cable is fully extended. It overshoots the pin by roughly the same amount. It can be put on the pin by retracting the cable slightly, shown in the first picture



No grinding noises or other sounds that would indicate 1st/2nd are shot. I tightened down the shifter cable retaining bracket again. There is still *some* play in it so I'm going to add washers under the bolts and see if that changes things, but it probably won't.

The gears will engage by hand, at least it feels like they do. At this point, I'm going to try disconnecting the cables, engaging the gear by hand, and then getting in the car and letting off the clutch to see if it moves while the car is running. Now that I finally got all the intercooler plumbing clamped and ran the car for a good 10 minutes, and it's almost running right, I can properly test the transmission. It was hard to do when the car would just sputter and die after a few seconds.

Also going to try draining the fluid and refilling.

Don't think this is clutch/hydraulic related because the car still goes in other gears...

[Alan M]

Have you fitted the cables properly at both ends and to the correct location considering this is a full swap.

[DWBF1]

First thing I checked was the cable routing, all appears as it should. And like I said the other gears work fine, so why would improper fitting cause only 1/2 to stop working?

Found out that newer 70series cars used a different retaining bracket on the M56 transmission than the 850 did. Ordered the part, it's arriving tomorrow, I'm hoping that a slight repositioning of the cables with the new bracket will solve this.

However, it would not go into gear by hand, so I am wondering if there's something wrong with the transmission internals. Really has me stumped.

[p fandango]

wouldn't a short-shift plate solve it, i know its not resolving the actual existing problem but if it gets the car drivable

[DWBF1]

How do you figure a short shift plate would solve it? By increasing the force/shortening the throw needed to notch into gear from inside the car?

[p fandango]

How do you figure a short shift plate would solve it? By increasing the force/shortening the throw needed to notch into gear from inside the car?

at the minute your cable isn't travelling far enough to select 1st & 2nd isn't it? With a short shift plate it won't need to travel that extra distance anyway. As i say its not fixing the original problem tho

[Alan M]

Did you fit your clutch correctly? It is marked as to which way it should be fitted.

[DWBF1]

Yup, we triple checked the clutch/pressure plate - but if in fact it were off, would that affect 1st/2nd gear alone?

[Alan M]

Usually all gears. Sounds like the cable movement is the part which is restricted if you can manually select the gears with the lever ontop of the box.

[DWBF1]

Using the levers on top of the gear box with the cables connected, I shifted by hand ON THE TRANSMISSION until the shifter INSIDE THE CAR was in 1. The car did not move forward when I started it in this position. I repeated the process (shift by hand on the transmission until shifter inside the car was showing in position 3) and the car moved forward.

Because of this, I'm thinking the gearbox itself is damaged.

[Alan M]

I misunderstood the earlier posts. I thought that you were unable to shift into 1st and 2nd with the lever but could do by using the plate on the box. If you can make 3rd,4th and 5th gears but no 1st and 2nd you may well have a faulty box. With the wheels off the floor can you selct 3rd upwards and get drive/wheel motion? If so you should be able to try 3rd upwards on the road as you should be able to pull away in 3rd then shift through 4th and 5th, that way you can make sure the car is working in those gears before removing the box for another or stripping. It may help you before you remove the box. I would still check the clutch assembly is fitted properly before condemning the box the the scrap heap. Either way it looks like you may have to remove the box for closer inspection.

[DWBF1]

Thanks Alan, that's the conclusion I came to as well. Sourced a new box this week, and I'll be pulling the engine this week and replacing the box. Unfortunate setback but it's probably either the shifter bushings or shifter fork for the 1/2 gears.