Axle/ Diff identification needed

[antarmike]

Axle fitted to my Douglas is AEC unit number F217 C 590

 

Diff ratio is stamped on threaded end of drive pinion shaft. (visible when prop shaft was removed. Diff ratio marked as 7.9

 

It is not a Matador diff having 20 teeth on the half shaft splines not 12. Diff is offset so half shafts have two different lengths

 

It is double reduction, spiral bevel to double (herringbone) helical gears as per Matador.

 

I thought it was a Mammoth Major diff but Mammoth major mkIII chassis types 3872, 3873 have listed diff ratios of 6.22, 7.12 and 7.92 :1

 

Has anyone any suggestions as to the axle or the diff.

[Ed Batchelor]

I always understood that the Douglas had a completely different back axle innards to a Matador. As for where they got the heavier bits from cant help there Im afraid. Must be someone in the timber world who will know.

Maybe Martyn Callaghan?

[antarmike]

Can anyone PM me Martyn Callaghan's current contact details?

[antarmike]

Apparently it is a Monarch Axle and Diff!

 

Bits that should be part of the driven spiral bevel gear.

Stripped gear they came from

some bad chipping on the driving spiral bevel gear.

Both Herringbone helical gears seem undamaged, I hope I still find this after stripping and closer inspection!

[gritineye]

Not a windup, but just out of interest, where you using FWD and do you think the use of chains on the rear only had anything to do with the breakage?

[antarmike]

Yes I was in four wheel drive and I think the chains I fitted when site was really wet on the tuesday I arrived and the next day contributed to the problem, because by the time of the breakage the ground had dried hard. A brief period of rain on the day of the break softened the surface of the ground, and when I was pulling hard front wheels could slip in the soft surface, back wheels were locked to the harder ground, and in nlow ratio too much torque was applied to the back axle doing the work.

 

I have also found that the drive pinion back to back taper rolling bearings are not locked up tight, and I suspect that the tab washer has let go on the locknut and the fundenmental cause of the problem was incorrect mesh of the two bevel gears due to excessive clearnce in the taper roller bearings in the input gear.

 

However had the chains not been on.......

[philb]

That's what happened to my Matador (lock nut working loose) but I luckily caught it before any serious damage was done - only to the bearings. I know of two other Matadors that had the same problem - both leading to more extensive damage.

 

Lubrication of the front taper-roller bearing is not too clever, relying (I think) on oil thrown off the crown wheel and being retained by a weir plate in the housing. what was the state of the front bearing in the failed unit?

 

Given the ratio of 7.9:1 and the overall design, I'd be surprised if the wheel and pinion was not the same as in the Matador axle. Have you disproved that?

 

Phil

[antarmike]

Martyn reckons it is the same. I have not had time yet, I am trying to Identify my pile of rear diffs to find the best one before I attempt tp fully strip good and buggerred ones.

[Ed Batchelor]

Doesnt help your cause, but a chap who seemed fairly clued up on matadors/timber advised me that if one has a lot of load hanging from the jib it is advisable to avoid sharp turns combined with sharp use of the clutch/throttle to avoid snapped halfshafts. I guess with a light front and more grip on the rear the back end can easily become overloaded.

Obviously this is not whats happened in your case Mike regarding turning and halfshafts but an interesting anecdote that might save someone some bother one day and is in a similar vein to your problem.

I dont suppose AEC monarch axle parts are too easy to come by, if anyone can track one down it will be Mr Callagahn!

[antarmike]

Doesnt help your cause, but a chap who seemed fairly clued up on matadors/timber advised me that if one has a lot of load hanging from the jib it is advisable to avoid sharp turns combined with sharp use of the clutch/throttle to avoid snapped halfshafts. I guess with a light front and more grip on the rear the back end can easily become overloaded.

Obviously this is not whats happened in your case Mike regarding turning and halfshafts but an interesting anecdote that might save someone some bother one day and is in a similar vein to your problem.

I dont suppose AEC monarch axle parts are too easy to come by, if anyone can track one down it will be Mr Callagahn!

 

I have enough parts to build a diff from stock. It is just a question of which bits to use and how to do it.

 

Simplest is to change the innards of the diff itself, (needs 10 ton press and some big tubes, (and the holes two halves of diff housing are reamed through along with the holes in the LOarge spiral bevel gear on assembly.) Using old parts (diff housing spider etc from duff diff into spiral bevel of a good diff) means no metal left for the reamer to take out should the holes not line up. But diff I want to use also seems to have lumpy bearings in the input bevel gear shaft that will need changeing......

 

Alternatively change the bevel gears in the existing duff diff. This means re-setting depth of engagement and I do not have access to a full set of shims.....

[timbertractor57]

i was lucky enough to find lift on the input shaft on my douglas diff early this year, and a new set of bearings and seal was fitted before anymore damage was done.........at least the bearings and seals are available for sensible money