Type 9 Gearbox in a Roadster

[jon_cox]

Re: Type 9 Gearbox in a Roadster

Plenty of food for thought... Tonight I'm going to measure the angle of the spring plate to see if I have an old axle or one of the newer ones

To be honest Andy, I would not get too hung up on this. In the original Marina application, there was a centre propshaft bearing which was solidly fixed at exactly zero degrees of inclination. BL in their design update modified the axle to give a diff nose down inclination of 3 degrees purely to compensate for all the issues as I mention in my previous post. They calculated that with the weight of the loaded car, constant power at normal road speeds, leaf spring rates, leaf spring wrap etc that this was the best angle to achieve a zero-zero inclination difference during "normal" driving conditions.
The roadster has different dynamics to a Marina so you can confidently predict that this angle can be reduced to achieve the same effect.
You have measured your car to have a 1.5 degree inclination angle at the gearbox flange and 3.5 at the diff. The difference is 2 degree which I would say was pretty spot on. In the dynamic loaded state of "normal driving" I would expect to see a zero-zero inclination difference which is what you are after.

[andyf]

Re: Type 9 Gearbox in a Roadster

So I inspected the spring plates and they have the shims fitted so that answers that question. I also checked the horizontal alignment of the engine and gearbox in the chassis and it works out to be 0.7 degrees off centre. I don't think that pinion angles can be my problem.

The next thing I was considering doing was to have the propshaft balanced as it was not done when they shortened it.

Other than that I'm fresh out of ideas as to why it is noisy

[Ye Ol Ripper]

Re: Type 9 Gearbox in a Roadster

Hi Andy
Usually on a full length propshaft in a conventional road car, If the propshaft is out of balance then there will be a vibration at a certain speed eg 60-70mph.

If it's bad enough that vibration can cause cracks in the rear of the gearbox housing.

With a Roadster Prop, because it's significantly shorter than usual perhaps the balance issues may not be so pronounced or as critical.

Regular greasing of the UJ's provided they don't have play in them, will also help smooth running.

Does your current setup allow for a bit of movement back and forth where the prop meets the gearbox?

Iirc my Marlin Roadster prop can slide in and out a bit on a spline.

So I'm wondering if you don't have any give or sliding joint , could it be therefore putting stress on the gearbox output shaft/components?

[stevejgreen]

Re: Type 9 Gearbox in a Roadster

Not all UJ’s fitted in a Marina propshaft have grease nipples. With the angle that a modified Marina propshaft can sweep through, its entirely possible for a grease nipple to be swiped off by the joint itself.
It is true that unlubricated bearings can fail, and propshaft UJ’s are often neglected, but some have no grease nipple by design, so are maintenance free.

I cannot imagine a single propshaft driving a floating diff that does not have a sliding joint at one end or the other.

[Ye Ol Ripper]

Re: Type 9 Gearbox in a Roadster

Hi Andy, iirc you are running a Pinto coupled to the T9. When the Pinto was fitted in Sierra's and Cortina's etc, I don't recall the engine sitting tilted in the fore and aft position (However it's 30 years ago ), when viewing the top of the rocker cover. i.e the engine and gearbox sat pretty much level.

So assuming I am correct about this, how is your engine sitting? (you could check by placing a spirit level on top of the rocker cover)

If your engine is tilted, then surely it is possible that the oil level in the gearbox will be different to the desired level, when checking via the filler plug hole.

With that in mind is it not possible that you have had a false reading and the gearbox's have been run low on oil causing the premature failures?

A quick way to check your gearbox level is to jack up the rear of the car until the Rocker cover is level with a spirit level on top. Then remove the filler plug and see how much more oil you can get in or insert an Allen key to dip stick it.

I would investigate that line of thought before my original theory of an unbalanced Prop shaft.

Steve :-
My Roadster Propshaft has grease nipples on both of the UJ joints , I am using the Marina Box, however no grease nipples have broken off in 40+ years. The sealed units are cheaper to make but because you can't easily add grease to them wear faster.

Although uncommon, I have encountered splines that have a bur on them making the prop stick when sliding into & out of the gearbox. They can be redressed with a file.

It maybe beneficial to drain your gearbox oil into a clean container and see how much swarf comes out. You could then strain it and reuse and try adding some Molyslip for Gearboxes , which will quieten things down and improve the gearchange. It used to be available in a syringe type applicator with a rubber hose attachment.


It used to be in a green tube , the following appears to be the current formulation.
https://www.ebay.co.uk/itm/MolySlip-...7d24%7Ciid%3A1

[Ye Ol Ripper]

Re: Type 9 Gearbox in a Roadster

I cannot imagine a single propshaft driving a floating diff that does not have a sliding joint at one end or the other.

My point exactly Steve. Has it been established that the sliding joint can and is functioning?

Is it not possible that the propshaft has been made a tad too long and is effectively being forced into the rear of the gearbox , which could cause excessive pressure ,when the diff twists into a certain position?

There needs to be a bit of play to allow the prop to move forward & back as needed.

Has the splines & the corresponding joint been checked for burrs, that could prevent it from moving back and forth to accommodate the Diff movement?

This is the second gearbox that has happened to, so the route of the cause must be established to find an effective solution.

[andyf]

Re: Type 9 Gearbox in a Roadster

I have checked that the prop can slide in and out of the gearbox tail housing and has plenty of slack to account of the movement of the axle. In fact it looks like it slides less than half an inch given the marks on the shaft. I have some molysip to add to the oil but it was so full of oil that I couldn't get any in. The next thing that I am going to try is to jack it up more on the passenger side so that the oil runs away from the filler plug to see if I can get some molyslip in. I will also get the prop ballanced just to be sure and adjust the gearbox mount so that it is horizontal in the chassis. Then I'll have to give it while to see how it goes.

[stevejgreen]

Re: Type 9 Gearbox in a Roadster

From memory, with my Type 9 and Dolomite sprint axle, 15mm of ‘slip’ was needed so we are in the same ball park.

Unlike an engine which has a pumped oil supply, a gearbox relies on spray lubrication from the rotating gears. I struggle to evaluate how a small change in level of a degree or so, in the order of a couple of mm, will impact on the splash effect.

[andyf]

Re: Type 9 Gearbox in a Roadster

I don't think that oil is the problem, I think that something else is going on... or I'm just unlucky

[Ye Ol Ripper]

Re: Type 9 Gearbox in a Roadster

Andy , perhaps the gearbox got water ingress from being stored after being removed from it's original car.

It isn't too hard a job to drain and strain the oil You may even see some water coming out.

At least doing that is less labour intensive than swapping the Gearbox.


You could then refill to the correct level with the addition of the Mollyslip.

[stevejgreen]

Re: Type 9 Gearbox in a Roadster

It maybe beneficial to drain your gearbox oil into a clean container and see how much swarf comes out.

If only a Ford Type 9 and many other gearboxes actually had a drain plug at the lowest point.

[AndrewKB]

Re: Type 9 Gearbox in a Roadster

If only a Ford Type 9 and many other gearboxes actually had a drain plug at the lowest point.

Oh don't get me started on that old chestnut ;-) I couldn't agree more and really can't understand why Ford expect you to drain the T9 through the filler hole. Unbelievable!

[stevejgreen]

Re: Type 9 Gearbox in a Roadster

Didn’t mean to poke you with a stick Andrew, but Ford are not the only guilty ones.

If only it was that easy as suggested, reality soon kicks in when you search for a non existent drain plug, drop the gearbox, usually again, and tip it in several different angles to get the last drop out, after half of it has gone down your arm from the tail shaft after you pulled the sleeve out, thinking it was sensible, then flushing it with diesel etc, etc. and sweeping it with a magnet whilst thinking that most of the wearing parts are a bronze alloy so won’t be found.
If you find anything magnetic, the estimated bill trebles.

Can you tell, I’ve lived it.

[Ye Ol Ripper]

Re: Type 9 Gearbox in a Roadster

Ok fair enough I was unaware of the non existant plug on that particular box, however Is it not possible to drill and tap a drain plug in that gearbox in situ somewhere along its lowest point eg an M12 thread because the oil is thick, to speed up drainage versus an M8 or M10 hole?

Alternatively is there not a bolt on the lower part of the gearbox casing that holds the casing together that could be removed to let the oil out?

It would of course be necessary to know the exact positioning of the gears before drilling the drain hole?

If that isn't doable insert a tube through the filler hole and suck it out by vacuum handpump.

Surely that's easier than removing the Gearbox ?

[stevejgreen]

Re: Type 9 Gearbox in a Roadster

Do as I did with a Marina back axle whose differential had failed catastrophically leaving many steel particles inside.
The axles were never fitted with drain plugs either. It’s really not unusual. I did look at the idea of sucking out the oil, which was impractical as you could never be sure just where the end of the pipe got to as it snaked around the gear cluster.
Its nothing like sucking the oil out of an engine sump which has a pan to collect the oil and importantly a near vertical dipstick.
But with this particular axle, once it was off the car and drained of much of its oil through the opening where the halfshaft once was, with a fully dismantled axle I drilled and brazed a threaded boss and plugged it at the lowest point. Quite possibly the most pointless job I have ever done. It had lasted 30+ years without being drained and probably will last another 30 more after refurbishment.
I brazed the boss in place because I had no idea how thick the casing was at the lowest point, wanted a flat face for the plug to seal a washer on and have sufficient threads to be properly secure.

Drilling a hole in an oil filled gearbox would be an act of desperation, a solution if perhaps you were a CPO at sea and the captain was yelling at you because the ship was dead in the water, with the knowledge that it was emergency engineering, the amount of oil running down your arm was irrelevant, but most importantly the bodge job would be logged and the second you got back to a suitable port, the problem would be rectified properly.