Transmission Fluid for MkII
 

Hello Guys,
We were undertaking some annual maintenance on the Huntsville Legion Bren Carrier when we discovered that the transmission fluid had not been changed. After we unscrewed the lower plug, we were surprised at the "crud" that gooped out. Somehow, we forgot to change the transmission fluid during the tear down and rebuild of the carrier.
What is the modern day equivalent of 1944 MkII transmission fluid? The manual lists that it takes about 5 pints?
Thanks in advance - Richard

In the UK I will use EP90 to GL4 spec which is supposed to be ok with bronze parts unlike some of the other EP90 specs. Not all wartime ford boxes have bronze thrust washers on the layshaft, in which case and EP90 would be fine.....

I would go with 80w90, in the trans, and put the EP90 oil in the axle.
If your ford box does have bronze thrusts, the EP90 will eat them. Even if it doesn't have them, EP90 is probably a bit heavy, and make for (more) difficult gear changes.

Alastair and Lynn,

Thanks for your advice. I will cross reference the 80w90 and the EP90 here in Canada. I'll suggest we put the 80w90 in the transmission, we could use the help with shifting.
One more question, I don't see a transmission fill plug on the top casing. Do we need to pump it through the drain plug and look for an overflow?

Cheers - Richard.

Rich, There is a plug on the side, toward the rear. Fill only to the bottom of the hole (until it stops running out) when the carrier is on level ground. If you overfill it, you will end up with an oily clutch, which you definitely don't want.

Transmission Filler Location
 

Lynn,

Perfect, I have some 80w90 here at the shop. We will re-fill the transmission later this week. The carrier is sitting level in it's shed on the concrete floor so it should be fairly straightforward.

Regards, Richard

A few of my Land Rover owning friends have moved to 75W90 fully synthetic gear oil in there 4 spd synchro and non synchro gearboxes to replace the OEM spec EP90, so considering modern replacements is a worthwhile thought.

Alastair, I was thinking along those lines as well.

Most synthetic oils don't get along well with old type seals. I'd stick with the ordinary multi viscosity stuff to avoid a bunch of leaks.

David, I don't know when the carriers went over to a seal at the rear (do all MkII* have seals?) I don't know when the mod was introduced.
There may be no seals in it? Even if it has a seal, and leaks a little it might be o.k. in as much as the majority of carriers built, never had them.
We are talking the one at the rear of the box here. For those that are wondering, the Ford 4 speed only has a slinger at the front and no seal. Hence the reason why it is important not to over fit it (or leave it parked nose downhill)

What about the axle seals?

Sorry David, I was only thinking of the gearbox. I'd still put the EP90 in the axle.