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MG TD TF 1500 - Gearbox info needed

I'm going to buy another gearbox for a fall rebuild. I'd like to get one that has the sliding hub balls peened in. Does anyone know if there is a stamping on the gearbox case that would identify a later gearbox that has the balls peened in at the factory?

Tim
TD12524
Tim Burchfield

What you don't like chasing balls and springs across the garage floor. Seriously though they are not terribly difficult to deal with

I have a box out of a '53 TD but I haven't opened it up for inspection.
W A Chasser

Tim, do an archive hunt for "Gearbox Numbers". Bud
Bud Krueger

Bill, the disassembly is no problem. In fact the non peened balls disassemble themselves :-) It's the reassembly that is a pain. Bud, thanks, will do.

Tim
Tim Burchfield

Bud, I had actually read that thread some time ago and forgot about it. Unfortunately it doesn't answer the question. In fact there is some confusion about what the stamped number actually means. I did find a change in the sliding hub part number beginning with engine number 6533. But without knowing what car a gearbox came from and whether it is the original to that car it doesn't help much.

Tim
TD12524
Tim Burchfield

Tim - you can contain the balls when disassembling just by putting the gear in a small box before pushing the center piece out. Before reassembling, use a center punch to deform the top of the holes for the balls - just enough so you have to force the balls into the holes. Cheers - Dave
DW DuBois

Peening the balls sounds daunting but is really very straightforward, although having done it twice now on two separate boxes, it's much easier with two people. Horst demonstrates the technique in his book. He uses the punch after the ball is inserted & compressed. This is where the second person comes in. I found this was one of the easiest tasks on the whole car.

I believe that before separating the dog & hub it's prudent to mark their relationship. I reassembled both on the adjacent spline set, the reasoning being that the balls would now be bearing on an unworn section of the central groove. Also worth holding the still assembled dog & hub side on & measuring the difference between the faces on either side of the assembly. Barrie Jones believes the marked faces of the dog & hub should be reassembled so that they are on the same side. Cheers
Peter TD 5801
P Hehir

Thanks Dave and Peter, good advice as always.

Tim
Tim Burchfield

Actually Tim I used, as does Horst, a small cold chisel. It both compresses the ball & secures it at the same time. The force needed is somewhere between a tap & a firm strike. If you're going to have a go at your gearbox I have a rewrite of the gearbox section of the WSM. If you're interested I can email it to you. Cheers
Peter TD 5801
P Hehir

Tim this is from one of my posts in the archive & addresses the question posed in your initial post.

'I've discovered the gearbox number is stamped into the top face of the gearbox casing underneath the lid, along with the following info:

TD Gearboxes were made in numerical sequence, where the first letter is always T & the second letter is a letter from A to Z. The following 3 numbers ran from 001 to 999.

With TF boxes the first letter was U, the second a letter from A to Z, with the following 3 numbers again running from 001 to 999.

Y-type boxes used the same format, where S is always the first letter & the second letter was a letter from A to Z & also numbered sequentially to 999.

The following is from F.6 of the manual:

Gearbox No. TF 513. Engine No.3114 Balls peened.
Gearbox No. TF 939. Engine No. (?) New 3/4 shaft with circlip.
Gearbox No. TJ 800.Engine No.6533 Additional ball added & new 3/4 shaft with indent.

So TF513 (a TD gearbox!) came before TF939, and TJ800 was about 3,000 later (they didn’t use letters I or O).

Engine numbers can be misleading because engines and gearboxes were both made in batches, so an early engine could have had a later gearbox fitted to it or vice versa. Because of the age of these vehicles it is also quite possible that a box may contain a variety of early & late components including gears, shafts & hubs sourced from a number of different cars'. Cheers
Peter TD 5801

P Hehir

Thanks Peter for both posts above. I will have the Gearbox DVD Rebuild and the notes that go with it soon and I have the WSM. Thanks very much for your kind offer. I do think there must have been some relationship between the chassis number and the gearbox because the service parts catalog lists parts that replaced earlier parts with the starting chassis number for the new part. For example the replacement sliding hub (I assume with peened balls) was introduced with chassis number 6533. So if one was sure that a gearbox came from a car after 6533 they might conclude that it had peened balls.

Regards

Tim
TD12524
Tim Burchfield

This thread was discussed between 07/10/2017 and 08/10/2017

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