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MG TD TF 1500 - TD Differential surprise

I was cleaning off the rear differential on my 51 TD to see if the ubiquitous TD designation was painted there. Instead I found the letters YH. Any theories on how it got there and what it signifies?

Thanks

Tim
TD12524

TW Burchfield

Vauxhall, possibly.
T.A. Sirp

T.A, upon further cleaning it looks like YB which makes more sense since there was an MG YB. I wonder if it was a factory install or more likely a retro fit somewhere in the car's 65 year history. If it is a YB differential I'm disappointed that it is the same ratio as the stock TD diff.

Tim
TW Burchfield

YB makes more sense. Of the MG family & a contemporary of manufacture.
T.A. Sirp

I remember when the first of these stencils was reproduced in the BBS, I wrote a stiff note to say that I would be very surprised to find that they were factory. In the many dozens of cars I had worked on, I had never seen - or noticed - stencils

I write publicly, again, to say that I was oh, so wrong! They are indeed clearly factory. In fact, for a TD I restored last year, I made up a paper stencil to add the letters!

I love learning things about these little cars, and am grateful to all for the education.

Tom Lange
MGT Repair
t lange

I first saw the TD & TF stencils on Chris Couper's site in the gallery. Someone here sent me a stencil a couple of years ago which I then used on my TD. This may be of some use to you Tim. I'd post it here but I only have a bitmap version. Cheers
Peter TD 5801
P Hehir

Peter, I may just leave it as is. sort of a conversation piece. The gear ration is the same as a stock TD diff. The only visible difference I can see is shock mounts that aren't on a stock TD diff. I'm still toying with getting a lower ratio diff. Maybe there is a active market for MG YB rear axles.

Tim
TD12524
TW Burchfield

Tim,
Interesting information this as your car is not the first TD I see with a YB rear axle. If not stencilled they are easily recognizable by their extra brackets (as you've already mentioned).
It's highly likely that the YB axle is identical (same track width/gear ratio) to the TD's except for those brackets. It was introduced at a time when Nuffield went through a rationalization phase whereby all their products got the Nuffield split type rear axles introduced on Morris and Wolseley cars in 1948. Replacing the older banjo models. Not only the Y-type got a split rear axle and became the YB but also the Riley RMA and RMB which became RME and RMF respectively.
But now the intriguing thing: there was only one of the 1301 built YB's exported to the USA, a few to Eire and the rest were "Home Market"....
And: YB's entered production in December 1951 but the first thirty or so still got a banjo rear axle; the first split type appearing in January 1952. Your TD is assembled in December 1951. Could it be that Abingdon was using up old stock banjo axles on the YB and in the meantime put the new split axles on the TD's ????
In other words: is your TD one of a batch of probably 30 cars factory fitted with YB rear axles ????
Just my 2 cts....

Nick (TD3232)
Nick Herwegh

Nick, thanks for the information. I wondered if the YB differential could have been installed at the factory. I will now claim (totally unsupported by real facts) that my car was one of the first to get the split axle. Seriously, if the YB axle was not put in my car at the factory then it could be that it has the axle from the only YB imported into the US. That's my story and I'm sticking to it. I'd like to find out if that YB imported into the US is still around.

Regards

Tim
TD12524
TW Burchfield

For what it is worth, my TD (TD3042) built in August of 1950 has a split rear axle. To my knowledge there was never a change to the rear axle and I have no knowledge that there would have ever been a need. Granted it had a cosmetic restoration 42 years ago, but no mechanicals were ever changed, It retains all of its original mechanicals.
So I contend that the split rear axle was used in TDs well before the January 1952 quoted by Nick.
Or am I totally misunderstanding this whole discussion?
LPalmer

My TD nr. 11201 from sept. 1951 too has a YB type axle. I took the right bracket of the axle to fix a panhard rod (from the Y tourer) into my TD. Combined with the anti roll bar at the front makes a good driving.
Klaus
Klaus Harthof

Lou, the MD Service Parts List shows an axle change in December 1951. Starting with chassis # TD0251 the axle part number is A2342. The part number changes to A2370 starting at chassis number TD12285. TD 12285 was built on December 10, 1951. So it would appear that there was a change to the axle about the time mentioned by Nick above. The MG Y website also mentions the introduction of a new rear axle around the same time.

Regards

Tim
TD12524
TW Burchfield

Klaus, was the YB axle added at some point or do you think your car came with it installed? Did you use the MG YB front anti roll bar set up? Or did you use another method?

Regards

Tim
TD12524
TW Burchfield

All TDs came with the split type diff/axle. I have seen a number of TDs with the "extra" brackets, perhaps that was the part number change? George
George Butz

Perhaps I am misunderstanding.
I agree that there was some change to the rear axle at a later point in time, but I see no difference in the general construction between the early and late axles. In my mind a "banjo" style axle has the "pumpkin" bolted to the front of the axle housing with the large hole facing forward. A "split" axle has two halves which bolt to each other with the bolts facing the near side (left side) of the axle case. The "banjo" axle allows the gears to be removed from the front without removing the axle from the car. The "split" axle has to be removed from the car to extract the gears.
No where have I ever seen the TC style "banjo" axle pictured in any TD manual.
What am I missing?
LPalmer

The part number change at TD chassis number 12285 concerns the swap from BSF to UNF threads.

Indeed: ALL TD's had the split type rear axle, only the Y-type changed from banjo to split with the introduction of the YB (as stated in my previous posting).

It is my guess that YB rear axles were used at random on the TD assembly lines. It seems that they appeared on some TD's even before the YB was introduced.
Service literature doesn't mention them.
Furthermore it's a mystery why Nuffield didn't standardize the YB axle for both TD and YB models (the extra brackets offcourse being superfluous on the TD).

Here are a few other (well known) TD's with YB rear axles:
http://www.ttalk.info/RearDrumHolder.html
http://www.dbraun99.com/mgtd15470/On%20Going%20Maintenance/Suspension%20Tune%20Up/slides/Rear%20axle%20bearing%20replacement.html

Cheers,
Nick (TD3232)
Nick Herwegh

Tim,
I don't know if the axle was origine or not. May be that the axle was changed because the engine is also a later one. (16000)
The front anti sway bar is from the MGB, bought from Brown and Gammons.

Klaus
Klaus Harthof

Thanks Nick. I feel better now.
LPalmer

Thanks Nick. I feel better now.
Lew Palmer

I've done over 100 conversions/ overhauls of the TD-TF-Yb rear ends.I have seen a good number of stencils on TD-Tf axles so they were marking them for a reason. Perhaps to identify the gear ratios? Nick has it right. After December 1951 the TD-TF axles used were built with the YB triangular bracket installed even though the TD-TF cars never put it to use.All the early 1951 axles I've seen were BSF where the later 1952 an up were SAE

Because the YB was born January 1952 I prefer to think the YB used the later TD-TF axle. Just kidding

Dave

Dave Clark Arizona

The factory that was turning out the axel units would have been making them for several different Morris/BMC makes and models. The stencil was probably required to avoid errors in despatch to the various assembly factories. I don't know if every unit was stencilled or just one on top of every crate load.

Matthew.
M Magilton

Matthew,
The factory turning out the rear axles was the ex-Wolseley plant at Ward End in north-east Birmingham, now called Nuffield Tractor and Transmissions Branch.
Here in the "F-block" (an assembly shop originally used for bren-carrier production during the war)the Nuffield Universal Tractor was assembled but part of the block was also used for manufacture of Morris,Wolseley, Riley and MG split-type rear axles.
The worm and wheel rear drive for the Morris Oxford Taxicab had its own special corner in the building.
As you say, it's highly likely the stencils were an easy way of avoiding errors in despatch (MG and Riley axles going to Abingdon, Wolseley and Morris going to Cowley).

Nick (TD3232)
Nick Herwegh

Good info Nick, thank you.

Matthew.
M Magilton

This thread was discussed between 24/02/2017 and 06/03/2017

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