MG T Type Gearboxes

[Steve Lines]

Please can someone school a newbie as to the interchangeability of different T gearbox types and remote mechanisms? i.e what will fit to what?

Thanks!

[Clifford Jay Lockrow]

The TC, TD, TF Gearboxes are interchangeable as far as bolting up to the back of the block. The thing you have to watch out for is the ring gear on the flywheel. The TC, TD, TF starters are different and the right flywheel gear has to be with the right starter. Without looking it up it is the flywheel number of teeth that is different.

[Tom Lange, MGT Repair]

The TC transmission is completely different from that in the Td and TF, and virtually nothing inside or out is interchangeable. The TC transmission is considerably more robust and reliable, and hardly ever wears out to the point of needing rebuilding - unlike the TD/F trans. The TC vs. TD/TF mounting bracketry is also completely different, and not interchangeable.

That being said, racers of TDs and TFs used to modify their chassis to use the stronger TC box, and I know of at least one street-driven TF that has a TC box (I'm sure there are more). TC transmissions come up for sale not infrequently; TD/TF transmissions come up for sale frequently.

Tom Lange
MGT Repair

[neil888tv]

HI Tom, how can you tell what gearbox you have in your car? I have an early TC0358 and am in the process of rebuilding the gearbox and have come up with a snag, The laygear has been lying in some water at some time and pitted about ten teeth on 3 of the 4 gears so needs replacing, I've looked around and have found several in the US. for sale. The part number stated AEC3172 which says for a TC but has a different number of teeth, so I'm wondering whether mine is a TC box after all. Are there any other options ie internals from another t type box or indeed Nuffield box or is it a new box altogether, I hope you can understand my problem and sorry it's so drawn out, your advice would be much apreciated,
many thanks,
Neil.

[Tom Lange, MGT Repair]

I would be very cautious about that cluster gear; if it is the one I remember, it has been offered all around for $650 as a TB/TC gear, but is completely diffrerent - not only in teeth numbers, but the teeth face the wrong way. Compare carefully if you have been supplied pictures. I believe the TC box has 15/26/31/35 teeth.

The TC box is robust and reliable, and I would be VERY surprised to find that you have anything other than a TC box in your car - I have never seen a non-TC box in a TC (except for the modern 5-speed). BMC made a lot of different cars at that time, and I would not be surprised to learn that the gear you have on offer is from a sedan of the time - an Austin or similar.

You are going to have to bite the bullet and get a genuine TC part - contact me off-line and I will give you the names of a couple of people who have good used TC parts. Also check the condition of the lay shaft, and check the end float of the cluster gear - you may need new thrust bushings.

Do you know the excellent article by Rick Storms on rebuilding the TC transmission? Well worth reading.

Tom Lange
MGT

[Tom Lange, MGT Repair]

Any further discoveries re: the cluster gear situation?

Tom Lange
MGT Repair