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Stuck in gear

Worth the effort.

Can then drop gearbox out down onto rollers in one lump. I'd do it.

Support the gearbox, cut the old xmember out, weld fittings for new one in. Fiddly with gearbox in place, but it could be done.
 
What a fantastic thread from start to finish. One of the most interesting and inspiring I’ve ever read.

Well done fulltimedad enjoy the satisfaction and well done to all the advisors.

Now then, on the subject of spare gearboxes I wonder if someone could help me.

I have an ex Norwegian military series III and was told by the PO that they were fitted with a ``beefed up heavy duty`` but extremely low ratio gearbox, ideal for pulling large loads up very steep hills. He also told me that the spare box, complete with bell housing and transfer box was a ``normal`` civilian box but after reading this thread it doesn’t sound like a ``normal`` gearbox exists.

If any of this is true or not, I’ve no idea as the PO wasn’t in anyway mechanically minded (his words not mine)

The part about the low ratio box is true as when I’m driving the maximum speed (with engine revs about the same as a jet engine) is 40 mph. The ex-military one I had in the UK many years ago would happily do 70 mph.

The first question I have is about transfer boxes,

Do transfer boxes have a 1:1 ratio for high range and lower ratio for low range? If it’s not 1:1 I was thinking I could try to swap the transfer box only to get a few more mph.

And the second is how do I identify what type of gearbox is my spare. I’ve taken photos of all the markings I can find on it and was hoping someone could tell me what I have and what all the markings mean.
 

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Thank you Dalts2904
It looks like changing from one transfer box to the other would give a slight increase then. I`m not sure what type is on there now and I`m not sure what type the spare is. Is there any way to find out what type the spare is from the numbers that`s on there?
 
Series 3 gear boxes identities are stamped on transfer case Series 2 gearboxes id was on selector cover side
Your spare gearbox looks to be a late series 2 suffix D gearbox with a suffix B series 3 transfer case , but the gear box casing looks to be the later series 3 box.
Can you check on front edges of the selector shaft covers should be a letter stamped either side and a corresponding letter below it on the gearbox casing.[thinking some one has fitted different selector cover hence two sets number]
What axles are fitted to your landrover/ would have thought they would have changed diff ratio as easier than different gear box.
 
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Could it be a 1 ton gearbox? The main difference is the transfer box which is all helical and much lower ratio as shown in post #765. If so, simply fitting a standard box, maybe the spare if it's in good order, should increase maximum speed. The 1 ton box should be worth a fair bit too! David
 
O
Arctic Ian said:
What a fantastic thread from start to finish. One of the most interesting and inspiring I’ve ever read.

Well done fulltimedad enjoy the satisfaction and well done to all the advisors.
Click to expand...
Thank you @Arctic Ian . Very pleased I managed to do it and it works . The help and advice on this forum was superb .

I can’t advise on your gearbox question sorry but whenever gearbox ID questions come up I’m mindful of the advice during my rebuild which was not to rely on what letter is stamped on the outside as the internals may be different . @Serious Series advice above should help with that 🤞
 
As mentioned before, you've probably got a 1-ton transfer box. They look pretty much the same but the bolt on rear cover on a 1 ton is convex rather than concave. Best way to check is drain the oil and see if all the gears are helical I suppose. The gearboxes themselves are the same so you would only need to change the transfer box.

I have a series 3 suffix A gearbox with the serial stamped around the selector cover and nothing on the transfer. Do you have synchro on 1st and 2nd? If you do then it's a series 3 box. On the front of the top cover of the gearbox on the side opposite the hand brake drum, there should be a letter or letters stamped on the cover and on the gearbox directly underneath. Do these letters match? If not, the top cover has been replaced at some point.
 
You can find out what the various ratios are on a box on the bench. I did mine recently. Put it into each gear and counted the number of revolutions of the input shaft needed to make the rear output flange to do one revolution. You can quite quite precise as there are 10 splines on the input shaft so each spline is 0.1 revs.

For the transfer box put the gears into high range 4th gear so the gearbox ratio is 1:1 then do the rotation - the output shaft will not be 1:1 it will be whatever the transfer box ratio is.
 
Grid Man said:
You can find out what the various ratios are on a box on the bench. I did mine recently. Put it into each gear and counted the number of revolutions of the input shaft needed to make the rear output flange to do one revolution. You can quite quite precise as there are 10 splines on the input shaft so each spline is 0.1 revs.

For the transfer box put the gears into high range 4th gear so the gearbox ratio is 1:1 then do the rotation - the output shaft will not be 1:1 it will be whatever the transfer box ratio is.
Click to expand...

Beat me to it. I did have a response typed up about counting teeth, but confused myself with maths :confused:

10 input turns will give you a higher resolution on the ratio, just divide both by 10 afterwards - For example, if you turn the input 10 times and the output spins 11.5 times, it would be a ratio of 1:1.15, a little more accurate than guessing the number of splines.

You could spin it 100 or 63 times instead if you wanted, but 10 is easy to divide and not going to take ages either. ;)
 
Thank you for all of the advice and information posted.

@Serious Series After reading the link to syncrogearboxes.com I now think that i have a spare gearbox that is a ``prefix 951.. used for British military, possibly only in lightweights, with EMC manufactured gears and with a modified layshaft gear cluster`` Not sure if that`s good or bad but it sounds good to me 😀

On the same web site I also found my existing gearbox listed (after managing to photo the serial number) and it seems as though its a ``prefix 246 easy change gearbox used in one ton and other special models`` I like the sound of ``easy change`` 😀😀

I think @erubus and @phoenixdave were right about the one ton gearbox (it also has a convex rear cover) and that coupled with salisbury axles which i understand have a lower ratio is what is causing my lack of mph.
Its not that i want to increase my speed its more that i would like to decrease the engine revs.

@Dalts2904 and @Grid Man I will follow your advise to check the ratios of both boxes before i start to do any work because as @Fulltimedad says whats on the outside does not always mean that is what is on the inside 😀
 
Arctic Ian said:
I think @erubus and @phoenixdave were right about the one ton gearbox (it also has a convex rear cover) and that coupled with salisbury axles which i understand have a lower ratio is what is causing my lack of mph.
Its not that i want to increase my speed its more that i would like to decrease the engine revs.
Click to expand...

As far as I know Salisbury axles fitted to Land Rovers are the same ratio as the Rover axles, it is normal on 109s to have a Salisbury rear and Rover front, so they have to be the same ratio. Just the 1ton transfer box will reduce your max mph to about 40 with standard axles. David
 
I don't think they did an overdrive that fitted the 1ton transfer box which is unfortunate as that would have solved your problem in the easiest way.

You could change the diffs for 3.54 ones which would give you a final ratio much the same as a standard series. Probably quite a good solution actually as you'd not have the same problem of too high a low box that you do with this conversion normally due to the 1 ton low box being much lower than standard.

Standard ratio in 4th gear, 5.4:1 (3686 rpm @65mph)
Standard 1 ton ratio in 4th gear, 7.19:1 (4900 rpm @65mph)
1 ton with 3.54 diffs in 4th gear, 5.42:1 (3699 rpm @65 mph)
Standard low box ratio 13.58:1
Standard 1 ton low box ratio 15.37:1
1 ton with 3.54 diffs low box ratio 11.58:1
Standard low box with 3.54 diffs is 10.23:1 by way of comparison. You'd still lose some low ratio but it would be approximately half way between standard and a normal 3.54 conversion.
 
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