GT4 no reverse, confirmation of next steps

Does your shifter go into the reverse slot all the way? I ask this because in the GTS the shift gate has a bump stop in position so to select reverse one needs to push the stick down to shift into reverse. If the shift gate is reversed things get weird shifting.


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Check the rubber bushing on the shift shaft.

 

Well that eliminates that as the issue.


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Russel, this almost like what happen to me on my 308 QV. I went and park diagonal against the curb for lunch, then after lunch I got in the car, put it on reverse and the car went forward. I had my friend help push the car back so I can get it straight on the street and only then I can go forward but I had to start it on 3rd gear until I got her home. What I found out was, one of the bolt that goes through the silent block came loose, some how the nut holding the bolt came off and the shift shaft was very loose. So, I got a lock nut re installed the bolt and everything is back to normal again.

 

I just did something similar over the weekend. I would advise looking at the bushings. My front bushing had no play that I could see. My rear had a bit of play and may need replacing soon. However, I was able to adjust the shaft to make things work. This could be your problem.

I would recommend taking off the shift gate and see if you can carefully feel the gear selection. You should be able to find reverse this way.

If not you may have to take off your pan to see if there are other issues involved.

Aaron

 

Russell
I think your problem is inside the gearbox, the adjustment process is one we used to do regularly on our race cars. It can be caused by unsympathetic use of the gear lever! For instance if you have left the car parked and in gear then someone jumps in and pulls the gear lever to get it into neutral without dipping the clutch, this can cause one of the selectors to slide fractionally on the selector shaft, then you are stuffed! Also if the driver is at all heavy handed with gear selection whilst driving and/or the synchros are a bit slow (like they can be when cold) and any excessive force is used to try and get a gear, same thing... the selectors will slide, game over.
So here follows the full process for re-setting the selectors. Start at the beginning and make sure that the gear shifter bearings are in good order, and the rubber bushes at each end of the long rod are good. Better still replace them with nylon or PU bushes. Then make sure the engine mounts are not broken and have not gone soft. Use a pry bar on them and see if they move around excessively when levered.
Assuming all that is good the next thing is to remove the bottom plate from the gearbox (it’s the big one...) drain the oil first and inspect for debris, inspect the magnetic plug as well. Carefully catch the springs, balls and spacers that will fall out, if they don’t fall out use a magnet on a stick to get them out and make sure you have the right number, (three balls, three springs, one spacer). The most important thing is to make a jig so that these springs and balls can go back in and operate correctly with the plate removed. Without this it is all a waste of time as the selector shafts will not be in the correct positions in neutral. I have used various bits to do this, one was cut from a old casing, a bit radical? Another was made of ali plates and drilled holes, but now we make a purpose made jig for the job which bolts up onto the adjacent studs. (You can get this from DTMPower!!)
To be continued...

 

I vote for 1st checking BOTH shift bushings. I had the same issue years ago. The mechanic was happy when he showed me the disintegrated busing. Trouble is, he didn't bother to test his work. And it was funny when he couldn't back the car out of the bay. Back up on the lift it went for the tougher-to-get-to bushing.

After a week as the bushings settled in, I did have to have the gear selector adjusted as it would sometimes miss 2nd and go into 4th.

 

The reason you need the balls and springs in place is that these hold the selector rods in the right place when the balls are pressed into dips in the rods.

(all the pictures are with the gearbox upside down)

Get a competent helper to sit in the car and operate the gear lever to your instructions. Have the car on stands and leave the wheels on so you can turn a wheel to help the gearbox shift. Once inside the ‘box the first thing is to centralise the primary finger in rotation so that it will travel across the input balls on the 3 bell cranks with them all stacked up in line one above the other when the gear lever is moved across the full range of the neutral gate from 1/R to 4/5 neutral positions.

Next is to make sure the 3 secondary fingers are all lined up one above the other with the bell cranks one above the other. It is just about impossible to adjust the 4/5 finger on its selector rod, so use that as the datum and move the other 2 if necessary by easing off the clamp bolt and sliding the
finger, re-tightening the clamp bolt.

It should now be possible for the gear lever man to move across the full width of the neutral gate without any of the bell cranks moving or being nudged by the primary finger.
Now starting with reverse get the man in the cab to select reverse and report on whether the gear lever hits the end of the slot in the gate plate. Looking at the dog hub or synchro hub see if it has gone as far into mesh as possible with the reverse dog ring. If the gear lever as hit the end of the slot in the gate plate chances are that the dogs are not fully engaged. Try the same thing with 1st. The aim is to achieve maximum engagement with both reverse and 1st without the gear lever hitting either end of the slot in the shift gate plate. Loosen the clamp bolt on the selector fork for 1/R and move it a little at a time until that movement is even between the two dog hubs.

The last two pictures show full engagement of the 2/3 hubs, and the selector shaft in front of them is the 1/R shaft and its clamp bolt.

Repeat this process for the other two selector shafts. In the end the gear lever should not be able to hit the end of any of the slots. Ferrari manufacturing tolerances being what they are it is sometimes not possible to avoid hitting one end of a slot, in this case (and for race cars where missing a gear is a big deal!) we would file the slot a bit longer so that full dog engagement is possible. In reality you should have 1-2mm clearance at the end of every slot the gear lever goes down.
You may have noticed some features of the ‘box in the pictures. It is a 328 ‘box which has bigger diameter selector rods, and wider webs on all the selector forks than the 308 ‘box. We also made up a steel mounting plate for the 3 bell cranks as the standard ali one is to flexible. The rods and forks in the 308 ‘box are quite flexible and prone to sliding about, so until we switched our race cars to 328 ‘boxes the above procedure was required quite often!!
Some alteration in driving style also helps a lot, so do not put your great big fist right around the gear knob like they do in the movies... use two fingers or an open palm to do the shifting with a pause in the neutral gate in every shift. You won’t get a bit part in a Fast and Furious movie but your gearbox will last much longer! Never, Ever, pull it out of gear when stationary without dipping the clutch.
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