raywin

raywin

Well-Known Member
I recently bought a discovery transfer box for my defender 90 TD5, I want to do a full re con on the box before fitting and I am looking at the available kits with seals bearings and gaskets etc.
I know that many of these boxes have been re built by people on here and I think I am all tooled up for the job, but just wondered if anyone would be kind enough to share their experience of overhaul kits?
Looked on the web and there are different kits available, started looking a bit deeper and what some people call OEM bearings and seals is not my idea of OEM, and I think its not only the little companies who use these.
Don't have the energy to do this again in six months so I want to ask for a bit of help from people who have found good kits (and maybe ones to avoid).
Appreciate any help or input here next project will be an R380 box I have sitting in the garage, hope to do the big swap some time this summer.
 
does it actually use gaskets ,with introduction of 300tdi t/boxes didnt use gaskets like prior and fitting or not to the wrong box drastically alters the shimming of diff and input gear ,sump gasket and hi/lo top gasket have no effect so personal choice, choice of output seal is determined by flange mud shield
upload_2016-4-4_17-39-27.jpeg

above uses ftc4939 obviously 2 needed one front one back

FRC6121.jpg

above use frc7043
input seal is the same for all boxes icv100000
id buy parts as you need
though buy timken bearings
frc5564 x 2
stc3185 x 2
frc7871 x 1
606474 x 1
stc1130 x 2 but are ball bearings so not timken but fag are excellent
you want 4 of frc6968
 

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Yes, I'd agree that it's probably better to get the parts you need individually, then you've got some control over the brand. That's what I did when I had mine apart over Christmas. The other thing you might need to replace is the output drive flanges because the bit the seal runs on gets in a bad way and it's difficult to get them oil tight. I had a slight weep on the front of the difflock housing after reassembly, which I cured a couple of weeks ago by fitting a new flange with no rust and pitting.
 
jamesmartin said:
does it actually use gaskets ,with introduction of 300tdi t/boxes didnt use gaskets like prior and fitting or not to the wrong box drastically alters the shimming of diff and input gear ,sump gasket and hi/lo top gasket have no effect so personal choice, choice of output seal is determined by flange mud shield
View attachment 99011
above uses ftc4939 obviously 2 needed one front one back

FRC6121.jpg

above use frc7043
input seal is the same for all boxes icv100000
id buy parts as you need
though buy timken bearings
frc5564 x 2
stc3185 x 2
frc7871 x 1
606474 x 1
stc1130 x 2 but are ball bearings so not timken but fag are excellent
you want 4 of frc6968
Click to expand...
James many thanks for the part numbers I wondered about buying the bearings separately I would prefer SKF, Timken, or Fag and I read somewhere that some kits use Chinese bearings which seems to be a wast of time and effort to me.
I haven't stripped it yet (laid up with flu at the moment) so don't know if it has gaskets or not I take your point about the effect of gaskets on the clearances, I need to take a good look at it and work out what I need.
 
i can give you any numbers, o rings etc, i but the gasket kit if it uses gaskets as you get o rings too otherwise i just buy them by number
 
I will make up a shopping list for bits, I want to change the brass washers behind the planet gears, and of course all the o rings and seals plus the spacer which is compressed to set the pre load.
Just took a look and the prices of the bearings is quite reasonable.
 
James
Maybe I could call upon your experience here.
While laid up with some violent bug the last few days I have been reading up on this transfer box, one common theme is the oil leak from the intermediate shaft, I saw a German page where they bore out the casing and re bush it with a steel insert.
Set me wondering is the problem that the o ring becomes compressed and hardened, or does the shaft fret in the housing and wear the casing bore ?
If the o ring seal is the main issue then I wondered about turning a small Aluminium cap to fit in the recess on the outside of the casing (see below) drill and tap four 5mm holes and put a gasket under the cap before clamping it down thereby transferring the sealing from the o ring to to cap on the outside of the casing

Buchse%20mit%20Welle.JPG
 
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the sleeve repair is something, i believe we first did back in the early 90s
it would be difficult to make a cap as gear box covers part of the shaft end, usually a new o ring and plenty of setting sealant on inner edge of o ring so as its pulled through with shaft is enough to cure leak , if its worse and that wont work a sleeve or another case is needed as shaft will move and thus put gear teeth out of alignment
 
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jamesmartin said:
the sleeve repair is something, i believe we first did back in the early 90s
irt would be difficult top make a cap as gear box covers part of the shaft end, usually a new o ring and plenty of setting sealant on inner edge of o ring so as its pulled through with shaft is enough to cure leak , if its worse and that wont work a sleeve or another case is needed as shaft will move and thus put gear teeth out of alignment
Click to expand...
Thanks for that James, I'll start off as you say a new one ring and a smear of good quality silicon, see how that goes, not 100% sure I will keep the discovery box I had the opportunity and thought I would like to re build one, see how the different ratio works out on the defender.
 
Still not feeling 100% but wanted to start having a look at what I have. Over the weekend read the thread by Bennehboy and input from James.


Looking at the end of the intermediate shaft seems that itv was not pouring oil out

Input gear is in good nick and the internal splines are hardly worn

Internals look sound if dirty, not sure about the selector dogs but take a closer look later.

Looks like a suffix "G" box
 
so I've been picking at this all week but felt a bit better today so decided to get it stripped so I can decide what to do. and what bits to order.
Thanks to James supplying P/Ns I checked the bearings individually.

Intermediate gears look good but like most of the components and the interior of the box are costed in black oxidized oil started to wonder if the vehicle has been slipping in snow or mud and hammering the internal diff + overheating the oil.

You can see here where the black coating on the diff has stuck to my glove.
Pretty straight forward to strip down, used the three leg puller behind the gear on the left side to pull the bearing inner race off, and after breaking the cadge I found the three leg would go behind the inner race on the right side, dogs were not too bad at all and change over ring looks OK too.
All in all condition of the box is not bad, just some concern about the diff.

Hmm muck

most of the gears and bearings were in good order but the brass washers in the diff you could shave with, they are quite thin, also there is some signs of wear in the pins (only one side ) here. Is there a set size (diameter) where they should be replaced? the planet gears are a bit wobbly but its hard to know how bad they are as I have never handled a new one, any guidelines anyone?

Easy to see where the washers finished up.
Going to start with a good fettling.
 
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All looks very familiar from my adventures back at Christmas. Those washers in the diff have been busy grinding themselves into a bronze paste. I wonder why?
 
Brown said:
All looks very familiar from my adventures back at Christmas. Those washers in the diff have been busy grinding themselves into a bronze paste. I wonder why?
Click to expand...
I understand that this diff is only to compensate for slight differences in speed of the two axles in normal use, if you get one axle bogged down and it starts to spin while the other axle is not turning then the diff is thrashing like mad, takes the brass washers out in no time, also it will overload the oil and burn it, I suspect this is the black oxide coating I am seeing over the parts.
Trick is to use the difflock as soon as one axle looses traction, and take it off when grip is restored.

How is your re built box holding up? Read your thread last weekend, before I got into this its a big help, I also intend to re man an R380 gearbox and swap both over together, the transfer box is from a discovery so it has the different ratio.
I am interested in how much play there should be between the planet gears and the two cross pins they run on in the transfer diff.
I imagine they are intended to have some play, when you look at my picture there is a bright spot on the pins where they have been loaded by the planet gears.
 
try then on an unworn part of shaft,usually its the shaft that wears and not planet gears but you do find worn ones at times, they should be a loose sliding fit ,and if diffs set up correctly should feel knotchy to turn with a by one of the output shafts but not difficult to turn
 
jamesmartin said:
try then on an unworn part of shaft,usually its the shaft that wears and not planet gears but you do find worn ones at times, they should be a loose sliding fit ,and if diffs set up correctly should feel knotchy to turn with a by one of the output shafts but not difficult to turn
Click to expand...
Think I will replace the pins and see how they feel, they are not so expensive and I would like to get the box in good order, the bright wear spots on the pins are localised so as you are saying I suspect this is the real wear.
 
So you think someone's been thrashing the centre diff?

Mine's fine as far as I can tell. Obviously, I replaced the diff mechanism as a complete unit so didn't delve inside its oily secrets. I'm getting a little transmission noise from the overdrive now, but judging by what I read online that's commonplace and it goes after a few thousand miles. With the overdrive and the low diesel prices I'm getting some good value motoring. Just filled up today after a trip to Heathrow and back (off at a conference in Korea) and the 240 mile round trip to the airport has cost me less than £40.
 
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I fitted one of those uprated crosshafts from Ashcrofts, if I'd had the cash I'd have probably bought one of their ATB centres.
 
I saw the uprated crosshaft but wondered if this is really a weak spot? Ordered the standard pins.
So I put in an order for the bits on Monday but not shipped yet I suspect the fibre diff spacers are not a stock item, so decided get on with a bit of fettling.

I find that the Screwfix economy white spirit is a decent de-greaser ( well ventilated room) and not too dear, usually dry the bits and clean down with brake cleaner then blow with air before assembling, to get rid of any residue.
Also bought a pack of sandwich bags from Aldi very cheap and you can put all of the bolts and bits together in their respective groups.

clean up the casing a bit, cant help wonder how some people get things so immaculate, I'm sure Arron would want these parts cleaner than this before taking them to the dump-it site, but they look a bit better, just need to scrape the silicon off the joint faces with my trusty old machine saw blade.
I have decided to spray the casing mat black when its done, to dissipate a bit of heat and to put some protection on the casing maybe make it easier to clean down in the future.

Output flanges have a bit of a groove where the old seal ran, I gave them a clean up but may decide to replace them before the job is done.

Funny some of the most valuable tools are the home made ones, looking to pull off the bearings with the three leg puller bit tricky with the hollow shafts, so decided to cut the end off an old mushroomed copper dolly,

dimpled it with a drill and pop it into the end of of the shaft give a great point for the puller to anker on
 
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