Thread: Adaptor shaft

Thanks Sitec. Got part way through your other thread then ran over to my zf auto on the shed floor for a look see.

Is the following too simple?

Buy this for about $100 from Ashcroft (as an example). Its designed to fit the LT230 input gear so no problems that end. It's what I'm assuming Sitec used.

Ashcroft Transmissions

Then the only machining needed is the development of an adaptor drive flange onto which to bolt the ftc5090 - same as zf setup. The adaptor drive flange of course bolts to the MSA drive flange.

So field service is pto cover and bearing support off. Remove input gear. Undo draw bolt (if not already broken). Pull broken bits of ftc5090 out. Put in new ftc5090 with new draw bolt. Reverse rest of process and drive on. This is assuming no damage to the adaptor drive flange and that you can get broken end of draw bolt out.

So how much to make up an adaptor drive flange?

I'm yet to find a picture of the female spline in the ftc5090.

Apart from continued use of the SAE10 spline and potential overall length of the ftc5090 what is the downside - why was this not a choice when compared to the one piece Sheldon/Outcast unit which still used the SAE10?

And you may have to swap out your LT230 input gear for the longer spline version (not 100% sure this is necessary) but say change over cost $300 (cost me $250 some years ago).

Popped this off a 1997 zf auto out of a DIsco 1. So it should match the long spline version sold by Ashcroft. Earlier Disco 1 fct5090s had a shorter SAE10 spline to suit shorter spline LT230 input gear.

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Is it possible to do away with the draw bolt? To stop floating, secure the fct5090 to the inside of the LT230 input gear by a 'c' clip, as in earlier drawings.

http://www.aulro.com/afvb/attachment...t-imgp3230.jpg

Ancient has come back with 4140 for hub and 4340 for shaft.

I could be misunderstanding, but it seems that 4340 is stronger than 4140 ie the shaft might be stronger than the drive flange. Could the shaft strip the drive flange splines in overload? To my way of thinking I would want the drive flange spines to survive at the cost of the shaft. Obviously if the two pieces are way stronger than the forces being applied then doesn't matter.

Trying to get a few links comparing both and their applications.

4340 High Tensile Steel | Interlloy | Engineering Steels + Alloys

This is interesting and supports Ancients recommendations

'In my experience, however, in sections where heat treatment results in >95% martensite, with comparable levels of cleanliness, and tempered to equal hardness and strength levels, 4140 will have a higher impact strength than 4340. This is contrary to 'common wisdom', but I have test data that supports it. This is mostly a trivial point, however, since in most applications where 4340 is preferred over 4140, the section thickness is such that the 4140 might not fully harden, but the 4340 will'.

4140 and 4340 alloy steel - Metal and Metallurgy engineering - Eng-Tips

For me, modifying the input gear is a non-starter - I want to confine any custom parts to the adapter itself.

Apologies if I've posted this before. I've thought about posting numerous times but don't think I've actually done it.

Knowing what my standard Salisbury axles coped with without breakage, I'm quite confident of using one of those as the basis for a shaft design of AM/Mudmouse style, utilising a SIII drive flange as Mudmouse has done.
An adapter shaft is going to see many times less torque than a halfshaft in a locked diff (which standard axles cope with reasonably). The 10 spline shaft in the LT230 is weaker than the Salisbury spline so any breakage should happen at the input gear end of the shaft. It should then be easy to remove/change should it ever break.

Upgraded material for the shaft would preferable, but even the standard LR axle material would be up to it IMO.

Only thing to sort out is the drive flange spline lubrication but there are a number of options for that and I don't see it as a show stopper. If it needs some lubrication every year or so for confidence then so be it.

To me the design ticks all the boxes - simple, sufficiently strong, able to be changed in the field utilising a relatively small/light spare, and keeps the LT230 standard. I also think there's half a chance a broken shaft could be welded sufficiently in the field as a "get me home" repair if you were really stuck remotely without a spare.

Steve

Would be great to see mudmouses pics of his, hint hint. I don't even know what a series3 flange looks like

Have read all this thread with interest............ with thoughts about another LR like Verns.

When I was putting the Ritters C9 / LT 95 TC late 70's conversion behind the Chev everything was apart to replace seals.

Should have taken photos I guess....... AFAIRC.... output from the C9 had been cut off and welded to some sort of female splined sleeve that mated with LT 95 input shaft, inside adaptor housing.

Remember thinking that it was a flawless big weld. Gets flogged, no probs.

Noel might still be working at Ritters and remember how it was done.

Just trying to say that welding can work.

cheers, DL

Hi SteveG, not sure whose design or what design is being referred to or if a mix, or is it general observation of what you would like.

My last drawing uses off the shelf land rover parts (or after market copies) proved in thousands of vehicles.

The exception is the drive flange which will have to be made - but even then it is copying the proved 20 involute zf output spline system - which does not get lubricated because there is no movement because it is bolted.

Only the SAE10 requires lubrication and that is taken care of by cross drilling, and oil feeder plate if fitted

The concept is probably much like mudmouses use of a S3 drive flange (...whip...crack...photos).

S3 , right, is 24 spline 31.5mm approx o/d. Spline length approx 30mm. Left is MSA drive flange.

S3 fange outside dia approx 113.5mm (compared to 120mm for MSA drive flange).

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