37 replies to this topic

[Jupitus]

Guys - I am cleaning up and rebuilding my gearbox for the 1275 lump and I have 2 boxes to choose from. The basic casing is the same on both (DAM5626) but the diffs have different casing numbers, one being DAM something , the oth a 22G type number.

Anyway - the main question is this: On the back of each diff housing is a sun-like imprint with 2 numbers in the middle, for example, 83|12 on the DAM4970 casing... I assume these numbers represent info on the diff inside but haven't found any id info... can anyone help?

Lastly, the side covers housing the drive output shafts are badly worn on what is the better of the 2 units... the other unit has the same part number on the housing side covers so I would think they are interchangeable... true or false, or something else to watch for please?

Thanks muchly in advance

[Jupitus]

Nuggets!

Started dismantling and got stuck at the first hurdle



Pic is stolen from Guessworks, but shows a cross-headed bolt on the engine mounting adaptor plate towards the lower left (top right of 4 fixings)... mine is knackered and I can't undo it!! I have tried cutting a straight slot with a dremel to get better purchase but it's still not shifting... can I dremel the head off and then get a replacement bolt? Will this work?

Edited by Jupitus, 10 June 2007 - 12:58 PM.

[Guess-Works.com]

Read nothing into the casting numbers on gearboxes, apart from DAM are generally A+ and 22G's A series... with the exception of the diff casing everything is interchangeable...

If the Philips bolt is most definitely screwed, what I do it drill the top off with a 10 or 13mm drill, and then take what's left out with a stud extractor when the mounting plate has been removed.

The sun like cast is a date of manufacture mark.

The only indication of the FD ratio within, is a coloured patch which would have had it printed on and stuck on the diff housing, but most of the time these have either faded or fell off completely..

[Jupitus]

Thanks alot Guessworks... the tabs on both are green labels (amazingly intact!)... I managed to get the philips bolt out with some brute force and ignorance... now I have a new problem... The input gear nose bearing plastic race is broken, and the innner race won't budge off the shaft for love nor money... I have tried levering as best I can and she still won't go... any suggestions? The circlip IS off, by the way

*Waves at Matt*

Edited by Jupitus, 10 June 2007 - 03:51 PM.

[Sprocket]

When you are at the stage of locking gearset to remove the input shaft and main shaft nuts, just undo the input shaft nut and this will push it off to a point that the nut is no longer on the threads. You can then get a large screwdriver and lever it off the rest of the way. The outer race in the flywheel housing will heed some heat to get it out, I leave this to my local transmission shop, they charge a fiver and that goes towards a couple of bears for the lad thats done it.

[whiskymac]

*Waves at Matt*

that aimed at me Jups!?

[Jupitus]

Bit of an update on my gearbox rebuild!

Made some reasonable progress yesterday (ok, I mean by my sloth-like drink beer and smoke and dawdle pace) and have managed to remove the diff, the mainshaft nose bolt, the nose bearing inner race, the pinion bolt, main bearing retainer plate, shim and layshaft guide plate, the layshaft and the laygear!

Couple of Q's:

1) The main nose bearing inner race was VERY tight on the shaft. Given that the plastic race had cracked, even though the bearings were in place, might this have caused excessive heat and the tightness of the inner race?

2) The layshaft has 2 needle races, one in each end of the laygear. These appear to be slightly different in size, can anyone confirm?

3) One of the needles in the races mentioned in 2 above fell out of the race - does this mean the needle bearing is trash?

4) I stopped because I had serious trouble getting the mainshaft retaining circlip out of the case - any hints on this? I have read that a set of 'large circlip pliers' are what to use (my circlip pliers don't quite open enough and I was trying with some long nosed pliers)... advice?

The crownwheel and pinion are 62 and 18 teeth respectively giving a final drive of 3.444. I'll be running a 1310 stage one-ish with an SW5 cam on 175/50/R13s... I think this FD should suit. Is it also sensible to count up ALL of the gears teeth to work out what ratios I have in this box or is there not a huge variation in these? I do have a 2nd A+ box which has a very badly damaged casing, but I could swap and change gears if I want to...

[Jupitus]

Innocent bump

I am also looking at how I can remove the mainshaft bearing... KC says he uses a slide hammer, and I have seen GW has adapted a diff cage as a specialist tool... for ease of getting this done I don't mind buying a suitable tool, but I don't want to get one and find it doesn't work... can anyone advise whethere this;

http://cgi.ebay.co.u...1QQcmdZViewItem

would do the job, and if not are there any links showing one which would please?

[Sprocket]

1) They are tight. If its the plastic thats cracked and the bearing rollers and races themselfs show no sign of deterioration, then the bearing will not have been overheating. The plastic sometimes cracks as a result of being expossed to all sorts of chemicals over the life of the gearbox. Dont be surprised to find the cage on the first motion shaft and the third motion shaft main bearings the same.

2)If the gearbox is the A+ then yes the two bearings are different sizes on the layshaft/gear

3) If the rollers are falling easily out of their cage, then the bearing unit is worn. Also check the surface of the layshaft where the bearing runs for marks and pitting, check the laygear for the same. failure to replace the shaft or gear in a pitted and marked condition will result in the life of the box being very short.

4)use the correct tool for the job. This task is still difficult with the right tool as the clip wants to slip off the pliers because there is little contact between the pliers and the clip as well as you pulling to remove it from the hole. Some come first time others take a few trys. Big circlip pliers are what you want and they are not that expensive.

The standard A+ gearsets were fairly common with only a couple of varying ratios on the Mini City E and the Metro HLE??. Yours sounds to be a standard ratio set with the 3.44 FD, have a search about, you will find the ratios some where. The older haynes manuals list the ratios.

The slide hammer will do the job, but you will still need to make up a tool o fit on the end. It will consist of a nut that fits on the end of the slide hammer, an old pinion/ mainshaft retaining nut and a piece of steel tube. Weld them all together and your good to go. You will also need some c shape spacers to slot between first gear and the main shaft bearing while you pull the mainshaft and bearing out with the slide hammer.

Hope that helps

[Jupitus]

Thanks alot Sprocket, that's helps muchly!

I'll reaplace some of these worn bearings and check the condition of shafts and gears carefully. I will also be counting all my gears on main and lay as I do have another possible A+ box to get parts from if ratios are different. I'll get some large circlip pliers, that's not an issue, but this bearing removal sounds like a right pain without the ability to weld, which I haven't... I'll shop about and use some imagination after taking a very close look at what's going on in there

Thanks again!

[Guess-Works.com]

simple tool to get the nose bearing off...

http://www.machinema...-bearing-puller

[Jupitus]

Hi JG! Thank you, but I think you missed an update... the nose bearing I got off by ondoing and unwinding the mainshaft nut and then some brute force (I'll need a new bearing, I know that)... I'm now stuck on the main bearing and it's circlip... I don't think a puller will work on that and you made up a tool, but I can't weld... can you find something on the market that would work for that? KC says he uses a slide hammer

Thanks again!

J.

Edit:

I think something like this:

http://www.machinema...tive-hand-tools

but that's quite expensive for a one-off... are there similar but cheaper anyone knows of?

Edited by Jupitus, 19 June 2007 - 03:54 PM.

[Sprocket]

Thats the tool you need to remove the bearings from the transfer case.

This is what you need

http://www.turbomini...p...vt&tid=8833

[Jupitus]

Thanks Sprocket, that's a nice clear guide -I have a local friend who has welding gear so I'll ask him for help

[Jupitus]

Update time! I tried making a slide hammer type device with some help, but the welds broke sadly, so I'm still stuck with the input shaft bearing in situ... how likely is damage if I do try to drive it out? I have a mixture of punches... also, when I was fiddling about I managed to move one of the bits and got a ping of balls and springs (don't think I lost any)... am I right in assuming that although not ideal this is not the end of the world?

P.S. I'm signing up on a welding night school course!!