V8 4 speed gearbox - difficulty with reverse.

jp928

Active Member
#1
The forward gears work fine, but getting into reverse is marginal, and unless I keep pressure on the lever it slips out very easily, and silently. Anything obvious I can look into please? The tunnel boot seems fine...
thanks
 

harveyp6

Well-Known Member
#2
Difficulty getting into reverse and jumping out of reverse are probably not connected.

The former can be clutch spin caused by low oil level, tight spigot bearing running clearance, clutch not bled preoperly, or the clutch linkage incorrectly set.

Jumping out can be caused by play in the gear linkage, incorrectly adjusted reverse selector stop bolt, selectors or reverse light switch, or the carpet bunched up behind the lever.
 

jp928

Active Member
#3
Thanks Harvey. Box has just been drained and refilled with correct oil (was an EP); clutch lever re-adjusted to 1 spline ahead of vertical. From underneath I can see a bush in the selector shaft - whitish plastic/nylon - which protrudes several mm below the metal of the shaft. Cannot feel any sign of a detent in the selection, but thats probably not unusual. Guess I will have to lift the tunnel finisher and check the state of the spherical seat. I see in other posts of yours a link to a diagram of how the shifter parts fit together, but it no longer works. Apparently the parts book diagrams are misleading ?
 

jp928

Active Member
#4
This is my lever. I think this is a plastic acorn type....without its acorn? The polish just above would indicate rubbing on something that shouldnt be there. Its almost exactly 12" long bare of the knob etc/ Long type? Car is 74, chassis 481...D.

One of the vendors sells a replacement acorn - is this a viable approach? The rubber boot has a small crack in it, so will look into replacing that .
thanks
 
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Demetris

Well-Known Member
#6
If you are talking about the replacement acorn from Wins, then it should be fine. I have used this for couple of years now.
 

mrtask

Well-Known Member
#7
I think I would be tempted to replace the spherical bush while you're at it, given their propensity to disintegrate. The plastic seems to get more brittle as it ages, and darkens over time. Yours looks to be the same colour mine had become when it expired. Also available from Geoff at Wins.
 

jp928

Active Member
#8
Have ordered the acorn from Wins, but the seat seems to be in good condition - no cracks, not dry, soft, pliable. Will perservere with it for a while. Scott at oldrubber lists the seat part, so hopefully it will be available faster than UK postage. The big rubber boot doesnt seem to be listed by anybody, so I may have to patch it up.
thanks.
 

mrtask

Well-Known Member
#9
WHich big rubber boot? The round one on the underneath of the tunnel? Geoff at Wins has one of those, I've just returned it to him unused as I opted for a different solution for my cobblefabbled LT77 installation.
 

harveyp6

Well-Known Member
#10
Apparently the parts book diagrams are misleading ?
They are. I used to be able to post a link to the relevant page in the parts book to explain the problem, but those links no longer work. If you can scan and post the page then I will be able to do the same.
 

Penguin

Active Member
#13
just noticed part of my reply is missing, change the gearbox mount, a soft saggy mount lets the box sit low which helps pull it out of reverse
 

jp928

Active Member
#14
Thanks. As soon as I get the acorn fitted will check the mount. Is there a way to refurb the original mount with new rubbers? MGBD say they do an exchange refurb, but that not very practical to do from Oz.
Harvey, here is a scan of the 1973 parts book page. Diagram is same as later parts books, just fewer optional levers listed. If people dont have a copy of the 1977 parts book I recommend it - index in front by description of parts, index at rear by part number are very useful.
 

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jp928

Active Member
#16
Found a new rear mount at Wadhams. Can anybody advise the procedure to replace the rear mount rubber part please? Nasty ?
thanks
 

Penguin

Active Member
#17
a couple of the bolts are a bit fiddly, but its just a case of supporting the gearbox and unbolting the heavy iron gearbox crossmember
 

mrtask

Well-Known Member
#18
371169, yep, Geoff's got one of them, unless somebody else has bought it in the last three weeks since I returned it to him unused.
 
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