question Bedford MJ Transfer Box

[LoggyDriver]

I was under the Bedford last night greasing up for the journey down to Trucks and Troops today. When I got to the front prop shaft UJ at the Transfer Box end I noticed some play in the drive flange that comes out of the Transfer Box. The drive input and rear prop output flanges are nice and tight with no play, but the output flange to the front prop has quite a lot of play.

 

I took that end of the prop off and had a look. The play goes in all directions, in/out, sideways and up and down.

 

I tried to tighten the nut but it's not moving 1mm so re assembled the prop. The UJ on the prop also has play that end and I'm assuming this is a result of the play from the output flange?

 

The Transfer Box is a BRAND NEW MOD FITTED ITEM two months before it was cast. There is no leak coming from the output.

 

I looked at the parts manual for a look at the breakdown of parts and it looks like there is a front wheel drive clutch inside the casing. Would this be the cause of the play?

 

So my question is, should this have play in it or not???? HELP:shocked:

[N.O.S.]

I had that trouble - not excessive, but enough to warrant doing something. ISTR there was a very thick spacer washer between flange and nut, I did get another (yes, from Maidstone Kia!) but it didn't make too much difference.

 

What is your propshaft like? The sliding splines get very bad so you can lift the prop up a fair bit, and it is that constant radial movement I think which trashes the U/Js and then starts on the transfer box flange.

 

I put a N.O.S. prop on last year when I changed the flange washer, and within a year it is getting well worn again! Next time I'll get a quality propshaft made up, but space is very tight beside the 5 speed box for a bigger diameter shaft :cool2:.

[N.O.S.]

I just remembered why I decided to get a quality prop made - when I put the NOS one on I couldn't believe the amount of lift on the splines - really poor quality, not surprising it just gets worse

[LoggyDriver]

Thanks for your replys N.O.S.

 

The Transfer box is brand new so it should be OK, but it may have been put together roughly. The front diff end of the prop is fine, its the tranny end thats got play.

 

I had a look at a "still in service" Bedford MJ which belonged to 17 Port and Maritime Regt today and the output on that was solid.

 

When you undo the nut on the output flange, is it a left or right hand thread and is it removable insitue?

 

Cheers mate.

[protruck]

Hi Loggy. The manual doesn't say that it has a L/h thread and the NATO part number

says its a 13/16uns standard nut. so the chances are it is a standard nut. Part no 7085400

 

NSN 2520998053411

 

Hope this helps

 

 

Clive

....................................................

protruckservices.com

[Richard Farrant]

Hi Loggy,

 

Here are couple of photos of a failed front output flange. It may give you an idea of the internal layout. The flange is actually free on the shaft whilst disengaged, although the shaft and flange should both be rotating at the same speed. There is a bush in the flange and it might be a combination of a worn bush and a worn washer under the nut, that is giving it more end float. On the inside end of the flange are teeth which mesh with the sliding front wheel drive clutch, the teeth of which can be seen in the photo.

 

The reason for this failure was that it was recovered with a front lift and the recymechs failed to remove the propshaft, this allowed the mainshaft to rotate but the flange being stationary. The front propshaft then became detached whilst on suspended tow.

[N.O.S.]

Richard, those photos remind me (age - memory - seive) that the washer makes little difference to flange fit as the nut holds washer up against a shoulder on the shaft. Also that the nut is locked by punching a thin hard shoulder on the nut into a keyway on shaft, so you'll need a new nut if you remove it as the critical part of the locking shoulder breaks away when undone (since it will stop at the same point when done back up!). Bedford part, not expensive.

 

 

Loggy - might be a good idea to remove propshaft and check if play is between flange and shaft only, or if the shaft moves around too (:shocked:). Also, while the prop is off stick it into 4WD and make sure the flange becomes locked to the output shaft and how this affects play.

 

I should be able to pick up my workshop manual later today so will have it to hand.

[LoggyDriver]

Hi Richard,

 

That's the kiddy. As mentioned my transfer box was replaced at ABRO Donnington a few months before release, so it hasn't seen any use apart from when I've had it. The retaining nut on mine has a shoulder like N.O.S. mentioned and you then have to hammer it into the keyway as a sort of locking tab.

 

N.O.S.

 

I did take the prop off the other day and had a look. The flange turns nice and freely on the shaft but there is end float and up/down and sideways movement of the flange. The shaft is solid with no movement. There is no oil leak so it must be sealed OK.

 

I refitted the prop and then engaged 4x4 to see if the play was taken up when the front wheel drive clutch was engaged but the play is still there. When I looked at the 17 Port and Maritime Bedford yesterday the output flange was solid, so it definitely shouldn't have any play in it. As I said this is a new transfer box so I'm at a loss why it passed inspection at the builders with excessive play in it.

 

I did notice this in the repair manual. The blue text refers to a spacer, do you think this might be the problem of a floating flange? The text in red I presume refers to the retaining nut that holds it all together?

 

61.3 Fit a new spacer, bore chamfer first, to the layshaft shoulder and

check that the end float of the layshaft driven gear is 0.23/0.35 mm

(0.009/0.014 in.).

 

62 Using jointing compound, assemble a new gasket to the attaching face on the

transfer box casing. Assemble the cover squarely on to the dowels and fit the

bolts after smearing them with jointing

compound. Tighten the bolts evenly.

 

63 Using a tubular drift, install

the layshaft front bearing in the

transfer box front cover. The bearing

locating ring must be in contact with

the face of the cover. Position the

washer on the front of the layshaft

against the bearing inner race and

install the circlip.

 

Fig 23 - Layshaft front bearing

installation

ARMY EQUIPMENT 2320-H-100-523

SUPPORT PUBLICATION

Chap 4

Sep 83 Page 13

 

64 Assemble the front wheel

drive clutch to the layshaft,

with the selector fork groove

in the clutch to the rear.

 

Fig 24 - Front wheel drive clutch

installation

 

65 Engage the striking fork rod

with the groove in the clutch,

at the same time entering the rear

end of the rod in the bore in the

front cover.

 

Fig 25 - Striking fork rod

installation

 

66 Smear the layshaft cover oil seal with Rocol anti-scuffing paste and

assemble the cover to the transfer box, using a new gasket. Install the

striking fork and locking ball, spring and retainer.

 

67 Before installing the layshaft universal joint flange, place a new O-ring

seal in the groove of the layshaft and smear the seal with gear oil.

68 Assemble the washer over the end of the layshaft, tighten the nut and

secure by staking it into the slot in the shaft.

[N.O.S.]

I have a civilian workshop manual and the detail is nowhere as good as the extract you posted. There is however a reasonable sectional drawing of the box - do you have this or do you want me to post it?

 

Sounds like shaft bearings are fine, and that a used prop flange with worn bush has been used on installation (probably not part of transfer box rebuild - my manual doesn't even mention the flange in the box inspection/assembly instructions).

 

Can't understand the fuss over measuring end float (regulated by washer wear) - all the extra movement would do is cause marginally quicker wear of the oil seal on outer face of flange. New bush and the wobble should be sorted, so need bush, nut and oil seal (possibly washer too).

 

Good luck!

[LoggyDriver]

I have a civilian workshop manual and the detail is nowhere as good as the extract you posted. There is however a reasonable sectional drawing of the box - do you have this or do you want me to post it?

 

Sounds like shaft bearings are fine, and that a used prop flange with worn bush has been used on installation (probably not part of transfer box rebuild - my manual doesn't even mention the flange in the box inspection/assembly instructions).

 

Can't understand the fuss over measuring end float (regulated by washer wear) - all the extra movement would do is cause marginally quicker wear of the oil seal on outer face of flange. New bush and the wobble should be sorted, so need bush, nut and oil seal (possibly washer too).

 

Good luck!

 

 

 

Thanks very much for your help. PM sent.