Not engaging reverse gear

[RobHomewood]

Advice requested please. I am having problems with engaging reverse gear on my P2 especially when hot. The gear stick will go into the reverse position OK but just whirs gently when I lift the clutch pedal. Randomly it sometimes works perfectly (eg 1 in 12 or more chance). It feels as it would if something is loose inside the box. I ahve adjusted the gate etc making sure the reverse position is not reaching the end of the gate slot. I am not an engineer and confess total ignorance of gearboxes never having worked on one but I removed the top cover to see if anything was loose but could see nothing obvious. So I decided to move the reverse fork towards the rear of the box ie reducing the distance between the fork pinch bolt and the selector pinch bolt. Not knowing what was a reasonable reduction to make I moved it 3/100th" ie reduced the gap between the pinch bolt bodies from 3.17" to 3.14". It didnt seem to make any difference. Is 3/100" a reasonable guess- or is it not the right scale of tolerance? Part of my problem is that the parts book etc doesnt show the gear leverage together with the gears so it is difficult to visualise the action/interaction. The nearest handbook says is just "Check all forks are fitted correctly and gears in mesh" when reassembling.
Any suggestions? I have a dearth of specialist garages here in Cornwall to take it too so would really prefer to sort it myself
Rob

[RobHomewood]

After lying awake last night worrying at this problem I have convinced myself that the amswer lies in the freewheel interlock. I am not clear how this works but it is supposed to take the freewheel into fixed mode when reverse is selected. Why it should also affect my gearbox when in fixed mode already, I dont know. There is a long spring (part 07290) in the reverse shaft which may be suspect so I shall look at that. Watch this space

[SHyslop]

I had been working towards the freewheel line but not having personally experienced the symptoms you describe, the connection was likewise eluding me. I had reached the stage of looking into a spare gearbox when I read your new post this morning and, if it is of any use to know, I make this spring to be 10 1/16" long.

[RobHomewood]

Well thanks for that info. The plot thickens. I havent discovered this spring yet. What I have realised this am is that there seems to be 2 shafts end to end (reverse shaft and freewheel shaft) and the cable passes through both. The spring I have found where the end of the cable exits the box is only about 2" long and what is more there is an additional shaft inside the flywheel shaft housing the cable with the spring over the outside. The parts book doesnt illustrate this additional shaft in Plate F or Plate H nor the relationship between them which doesnt help. At present I cannot see how this inner shaft and spring is held in. I think I shall have to open up the top of the box again and remove the reverse shaft to sheck the spring etc and the relationship.
I too might practise this investigation on the spare greabox.
Any additional info would be gratefully received
Rob

[GOY189]

Has the rubber support under the gearbox been replaced? As discussed in your post last July, they can go spongy and make gear changing difficult.

Mike Maher

[RobHomewood]

Thanks for reminding me about the gearbox support rubber but I think it is fine. I don't have problems with other gears just reverse and clutchless change works fine for instance. It seems my gearbox mount is different to the Parts book in that the top part has been replaced by a steel strap with rubber blocks under onto the gearbox housing. I dont know whether this was a Salmons version for DHC's or whether a previous owner has done this to overcome a problem. Anyway it seems quite a workmanlike effort so I dont anticipate changing it. You can just see the lower cradle and rubber in the photo with the strap fixed over the housing.http://www.rover-forum.thersr.co.uk/dow ... 4674e0638d

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Having just come off a Landrover forum this am I checked out the photo of my uncovered gearbox operating rods as it is recomended apparently that the pinch bolts should all be vertical to get the operating forks in the right position. Mine patently aren't vertical but as there isnt a problem with forward gears perhaps the verticality of the pinch bolts isnt critical? I may however try to straighten up the reverse pinch bolt and therefore alter the position of the reverse fork to see if that makes an improvement
Sorry for some reason the photos only want to be seen in the wrong order!

[RobHomewood]

Hi Steve Hyslop again. I have started opening up my spare gearbox and am looking for this long spring which is supposed to be in the reverse shaft. I have the cover off and can see the shaft but cant workout how to get the spring out. Unfortunately I cannot undo the ferrule on the end of the shaft and cannot take the shaft out - there is something resisting it. It certainly has a good spring in there somewhere. As you have just taken your spring out can you tell me how please? Do I have to separate the freewheel casing from the rest of the box to get to the other end of the reverse shaft? The manual gives no clues apart from 'remove' once you have the cover off!
Hope you can help as I cannot feel any resistance from a spring in the reverse shaft of the other gearbox in the car. Many thanks
Rob

[SHyslop]

Hello Rob, I've been out to take a few pictures which might be of use . I think I see what you're seeing, but if I'm wrong, just say. The long spring can't be reached without taking the freewheel off. It is completely internal to the two units.

Before you give yourself extra work, can I just tell you a quick tale from last year. It may be irrelevant but here goes. I had a non working freewheel and the culprit was the connection at the gearbox end which isn't an adjustment I had seen anything written about. It's all about the adjustment under the dash but what I hadn't fully appreciated was that when you operate the freewheel, two actions happen. The shaft you see poking out of the freewheel unit into the gearbox has two components. The outer one operates H40/H41 to move the freewheel inner in or out of mesh. However, there is also an inner plunger to H40 which compresses the long spring and has about 1/2"- 3/4" of travel . I can measure it more exactly tomorrow but it is a clearly visible amount. It would seem possible that adjustment of the cable at the gearbox end might help with your problem, particularly if you don't use the freewheel i.e. it could be adjusted completely and definitely "off" if that gave you a reliable reverse selection. My own problem was that the cable needed to be pulled more tightly through its fixing then secured to make it all work properly. You can just see the break right at the end of the shaft in the freewheel where the inner plunger meets the outer rod.

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[SHyslop]

Good morning, I hope these pictures may show a bit more clearly how this works. First, external spring fully released and fully "out":

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The other end of this shaft, with both plungers fully "in":

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Now the same end of that shaft with the outer plunger "out" :

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and lastly the inner and outer plungers both "out" (a bit blurry but I think you'll get what's happening:

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The outer rod's movement to operate the freewheel fork does not impact on the outer spring. It is only once the fork has moved and the further movement of the cable against the outer spring pressure that the inner plunger moves so it looks as if the correct operation can be guessed from external observation - provided, of course, the internal components are ok. There could be a metal shroud round the external spring partly obscuring your view but I think enough can be seen even with it on. Even if the inner spring were to break, it has nowhere to go and so would seem to stand a good chance of still working to some reasonable degree. I think that I'd be tempted to try a the application of oil on any moving parts of these components that you can reach and if, externally, they seem to be moving ok, try to feel whether adjusting the cable at the gearbox end is likely to be moving both plungers correctly. Should that not work then it's possibly a take apart job. I have found with the unit you see in the pictures that I can make the inner plunger stick "out" even with the outer rod returned to "in" due to the lack of lubrication.

Just for comfort in terms of working on these things, I've just received from Meteor a cylinder head rear cover for a 14 that had rotted to nothingness then it may be hacksaw time for a thermostat cover on another 14 which has a suspected failed thermostat then it's off to practice the organ for Palm Sunday tomorrow. A problem shared and all that.

[RobHomewood]

Wow! You have gone to a lot of trouble taking photos and giving info. Thank you. Its all useful stuff.
I had the freewheel working fine before and the set up seemd OK. But I have only just clocked the inner shaft (which you call a plunger) in the freewheel shaft where it pokes out of the rear of the box and I have never seen the other end so couldnt work out how it operated.
I shall now remove the the freewheel unit from the spare box to get to that long spring and to calculate whether the freewheel can be removed with the other box still in the car.
A couple of questions if I may? ( Or anyone else can join in)
Will the freewheel unit come to pieces when I remove it or will it stay whole so that it is easy to refit?
Do you think I can remove the freewheel far enough with the gearbox still in situ to get to the long spring and replace it, as I suspect it has disintegrated or was never there?
Many thanks in advance and good luck with the rear plate on the cylinder head and the thermostat. I replaced my blanking plate with a heater connection version and still have the original if you have problems. ( I have connected the plate direct to the heater take off at the water pump to improve water flow at the rear of the engine- no heater). I also have a couple of cylinder heads and other 14 parts in my spares if necessary but I am not sure whether they are 14's or 16's
regards
Rob
PS On checking my spare gearstick mounting I find that it is still connected to the upper part of the gearbox mounting (see previous post) so it is a mystery why someone has put their own version on my car!