Carrier shifting issue

[Jim Burrill]

Finally got Lance's Mk2 out to a farm to get some run-in time.

Starts well and has power. Turns fine.

At speed, trying to get shift into fourth gear is failing.

Shift lever goes int o the gate fine when exercising the shift pattern, but with engine running and carrier at speed, the gear won't cleanly engage.

No amount of finessing the shift lever will get it to stay in 4th.

SOme bit of grinding when letting out the clutch, but no worse than a sloppy shift in any other gear.

Seems the "throw" to move into 4th is short.

Off hand, anyone know of a fix for this?

[rob love]

Right way is to check engine mounts, and comparing linkages with known good ones for length.

Quick fix is to grind a little out of end of the slot (gate) in the shift guide plate up at the shifter.

If the linkage was apart, it could be a little play in the bolts holding the 3 parts of the tube together. Too short or too long will cause issues. Not properly aligned will cause issues. The four holes in the floor holding the shifter socket, or even the holes holding the shifter brackets on the floor by the driver can cause problems. Thin or warped floor can also cause issues.

[Michael R.]

Points made by Rob, but before cutting the speed change gate, inspect and test for:
1)Bent CTL 4950. Inspect also for excessive wear or corrosion that have lead to removing material inside the adapter socket.
2)CTL 4950 not replaced with upgraded replacement . . . if not a correct orignal MK-II* part, i.e.: supplied from a donor.

Performing the speed change test may assist to determine if the CTL 4950 is bent, or simply not properly installed on the shift lever. You could place a straight edge against the long side of the adapter to visually inspect it. Post war workshop modifications are observed with a section of angle iron welded on the narrow length of the adapter arm.

Have a look at the opposite side (male stub) to inspect the amount of wear inside the slot on the upright support bracket at the location the stub contacts the support bracket, as well as making sure the modification has been correctly installed on the support bracket and is properly held down by the two transmisssion top bolts.

I wager it is #1, with a pinch of the short side male portion inside a worn guide bracket.


Assumptions: the shifter forks are correct, and no internal issue with the transmission exists.

[charlie fitton]

I'd go with engine mounts and alignment of the engine.

If it used to work fine, but doesn't now...

[RichardT10829]

Tweaked the throw bar when you removed it.

As per Rob and Michael's comments also.

[Michael R.]

When the power pack is installed complete with radiator cooling fan and radiator cowl plates, the alignment of the engine will show in both the position of the fan inside the fan cowl opening, as well as where the transmission adapter fits against the differential extension. The tie rods can play a role in alignment. If the transmission adapter is correctly fitting the differential extension, I question how much (error) room is there for the shift lever to be out of place?

Unlike the U.C. MK-I* and MK-II*, it appears the original Bren carrier series had an adjustable shifter linkage. Perhaps Ben has one on his Scout, or Lynn on his Bren?

Internally, the original 3rd-4th transmission gear shifter fork was replaced. The original part number BB-7230 was replaced by C11T-7230.
"The replacement part has a reinforced web which strengthens the arm eliminating slipping out of gear and hard shifting."
(ref: Canadian Army Service Information Bulletin H-2, dated 14-12-42, #1900-11-42(M-1658)).

The attachment describes the procedure to test for an out of alignment shifting mechanism.

[Ben]

I have an adjustable linkage, somewhere in box. It's shown in Nigel's first book I believe.

[Lynn Eades]

Mine was butchered beyond recognition (cut out and welded into a fixed unit)
I am not sure how they were built one after the other with no real adjustment.
With so many components that could be slightly out, it is amazing that everything worked. I bet there were issues on the production line, or at least when they first went over to the fixed set up, pre war in England.

The adjustable system was probably canned because it too would have been a "for ever coming loose" nightmare.

Jim, Have you had any of the gear change apart, while the engine was out? If so, make sure you don"t have a "too long" bolt in the tube under the engine, that is hitting the floor before it is properly in gear.

[Jim Burrill]

Thanks for all the references and help!

In this case, we have not had the engine out since it came from the previous owner. He did say he had trouble going between 3rd and 4th, but otherwise the shifting is all functional.

After some engine cleanup - oil change, cleaned and resealed gas tanks, rebuilt the distributor ( Diver Helmet) and some carb cleaning it runs pretty well and has power.

But the whole tranny issue is new to us. Will see about the replacement shift fork from Mac's Auto and then see how bad the gears are. Usually 4th is pretty un-chewed.... especially compared to 1st.

A carrier Driver from the Middlesex Independant Machine Gun detachment with the 49th Div told me from D-day(+19) to VE day, he rarely had his carrier in 4th. Lots of 1st and 2nd convoy conga-lines.

[RichardT10829]

Must have been a very very slow convoy buddy.

[charlie fitton]

Check the engine mounts.

Remove the engine covers and have a mate watch while you put the engine under load in first and reverse.

If the engine "heaves" off the mount, then replace them.

f

[Rob Beale]

... on the splines of the short gearshift lever.

There was a discussion I heard recently amongst carrier folk about the possibility of being one spline tooth out. This would mean the wishbone was not at right angles to the vehicle axis when in neutral, and hence affect the throw.

Food for thought

Rob

[Michael R.]

Yes, ... that point needed emphasis. I recall you understand those fine splines very well Rob.

"Performing the speed change test may assist to determine if the CTL 4950 is bent, or simply not properly installed on the shift lever. You could place a straight edge against the long side of the adapter to visually inspect it."


See also: http://mapleleafup.net/forums/showthread.php?t=8560