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#Post#: 86205--------------------------------------------------
Gearbox rebuild questions
DIR By: clemo902
Date: March 10, 2014, 5:08 pm
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I have just stripped down my first gearbox and would welcome
advice from you knowledgeable chaps on here on a few things.
The box is out of a 1980 SWB 2.25 petrol and according to the
number stamped on the transfer box is a suffix B, with the first
numbers 904, which according to a website I found was started in
March 1980, following on from the 903xx sequence. There is a
rebuild plate on the bellhousing though, so I'm assuming nothing
may be original.
The reason for having a look inside was reverse gear was making
an horrible noise and I could not sometimes select 3rd or 4th
gears.
Having now completely stripped down the main box it appears to
be suffix A, and not a B though.
The reverse idler gear has a bush and not a roller bearing, and
the reverse gear selector fork has a suffix A part number
stamped on it (576704).
I assume that as the gearbox number is stamped on the transfer
box the main box has been changed at some point?
A few piccies
The condition of the reverse idler gear explained the noise
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0761_zpsb7f3b07d.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0761_zpsb7f3b07d.jpg[/img][/URL]
The corresponding teeth on the layshaft are also a bit scarred.
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0760_zps13473c82.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0760_zps13473c82.jpg[/img][/URL]
Something is missing from the other end of the layshaft.
I'm wondering if this missing chunk has caused the reverse gear
damage?
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0758_zps4189d821.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0758_zps4189d821.jpg[/img][/URL]
On the primary pinion that passes through the bellhousing is the
dull area evidence of the shaft having rotated on the bearing?
It seemed a tight fit so maybe not?
Also there is play on the shiny disc end of the pinion (where it
fits inside the 4th gear synchro rings). Is this normal?
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0763_zps20423b3e.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0763_zps20423b3e.jpg[/img][/URL]
The 3rd/4th synchro unit seems fine and I can move the middle
part to engage either gear without trouble.
Would this be ok to re-use or would it be better to replace it
anyway?
I'm not sure how worn the rings are.
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0765_zps41bb8fb8.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0765_zps41bb8fb8.jpg[/img][/URL]
[URL=
HTML http://s1324.photobucket.com/user/clemo902/media/DSCN0764_zps8a04e8d2.jpg.html][IMG]http://i1324.photobucket.com/albums/u611/clemo902/DSCN0764_zps8a04e8d2.jpg[/img][/URL]
I was going to replace all the bearings and gaskets anyway,
along with the layshaft.
With regard to the reverse gear idler I take it I cannot replace
it with the later rolling bearing type, but from the parts book
it looks like there is a reverse gear modification kit (RTC2344)
that has a suffix B layshaft and reverse gear.
Would I be better off getting this rather than a straight
replacement suffix A idler gear given that I need a new layshaft
anyway?
According to the green bible the new bush needs peening and
reaming.
I know what reaming is (anyone have a correct size reamer) but
what is peening?
That's about it for now.
Advice. comments, insults all welcome!
#Post#: 86208--------------------------------------------------
Re: Gearbox rebuild questions
DIR By: SteamPunk
Date: March 10, 2014, 5:33 pm
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My choice, having discovered this kind of damage, would be to
purchase a second hand gearbox in reasonable order and rebuild
that. (Renewing all bearings and synchro if required). I suspect
that this could lead you down a bad road.
Is this an option for you?
#Post#: 86214--------------------------------------------------
Re: Gearbox rebuild questions
DIR By: divie
Date: March 11, 2014, 4:04 am
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Those early boxes with the bronze bush are known to eat the
bushes. Some theory on problems using GL5 spec oil so on rebuild
use GL4 EP 90.
If you rebuild your present box I would change 3/4 syncro it is
just to much work to pull the box again.
Measure the shaft I may have a reamer that I could post to you.
Peening is an expression given to tapping with a hammer to raise
metal, sometimes done to prevent nuts coming undone. Things
rattling around loose can peen together.
#Post#: 86225--------------------------------------------------
Re: Gearbox rebuild questions
DIR By: Albert Ross
Date: March 11, 2014, 2:52 pm
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Be aware, the 3-4 synchro hub has a front and a rear. Your pic
showing the lines on the brass is the rear. It has a machined
groove in it. It fits over the spring clip on the mainshaft.
#Post#: 86246--------------------------------------------------
Re: Gearbox rebuild questions
DIR By: clemo902
Date: March 12, 2014, 3:12 am
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Thanks for replies, I will replace the 3rd/4th synchro as well.
I have been using GL4 EP90 and the actual bush is in good order,
it's just the teeth that are bolloxed.
Anyone know if the play on the disc that fits inside the 4th
synchro rings is normal and about this reverse gear modification
kit?
Divie- you may have guessed that the tool arrived - thanks!
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