Speedo cable driven gear color code

[BigBrother-84]

OK, received the replacement driven gear.
Gears, I would say.  At 5$ each, and the road trip next week, I didn't take chance and ordered 4 different ones:
• 16 Tooth for Automatic Transmission (the black one);
• 16 T Manual Transmission (purple)
• 17 T AT (green)
• 17 T MT (white)


Need help.  Seriously.
These gears are driving me crazy.

Q1 : Why the driven gear I found in Big Bro's Transfer Case (Borg Warner 1345) is the AT type?  Big Bro is MT T18 equipped...  Is a transfer case considered as an automatic transmission?


Q2 : Can I put a MT driven gear (short shaft) in a BW1345 TC?  Or, as the one I pulled off Big Bro, it absolutely needs an AT type (long shaft).

Q3 : I don't know why, but the 16 T AT (black) I received isn't like the other AT ones (see picture).
The tooth cylinder prolongs around its long shaft, so the shaft is just a bit longer.
If I cannot put a MT type in Big Bro's TC, do I have to modify the black one?
I can cut the tooth cylinder, should not be difficult, the bottom is at same level than the other gears top.
But if I can avoid it...

[Gary Lewis]

I've mixed auto and manual transmission driven gears w/o worrying about it.  As long as the drive gear has a good mesh with the driven gear I don't think you'll have a problem.  I think you said you need 16 teeth, so put that purple one in and I think you'll be happy.

[BigBrother-84]

I put the AT purple 16T (short shaft) and I noticed that I had to push it a little bit (about 2mm), like if the cable was a bit long for the driven gear shaft.
I was wondering if the cable was a bit “compressed” this way.
So, since I had on hands a long shaft 16T (but wrong model), I decided to take a chance and try to modify it.
Well, I think it could be called “success”.

Before:


After:


Road test successful, the speedometer is really precise, no more than 1% difference.

Very happy!

I take Big Bro tomorrow to go to a work site, 4 1/2 hours of highways.  This will be the final flight check before the road trip.

[Gary Lewis]

Well done!  And glad the speedo is pretty precise.  However, that doesn't mean the odometer is accurate.  So you should check the odometer against highway mile/kilometer posts to see what you have, preferably over a 10+ mile stretch.  Then you can apply a correction to your fuel usage as you go.  

[BigBrother-84]

Test completed.  On a relatively flat highway.  No wind, sunny day.

Real mileage travelled (road milepost markers) = 105 miles (169km)
Odometer measured mileage = 105.7 miles (171.1km)

Conclusion: Big Bro indicates a bit more than the real travelled mileage (+0,65%).

Probably less then the impact of a hilly road.  So...  I'm satisfied.

[Gary Lewis]

Wonderful!!!  So, how's the economy?  

[ArdWrknTrk]

Congratulations Jeff!  

Your odometer seems right on the money.

[grumpin]

Awesome! What a machine!

[BigBrother-84]

Gary Lewis wrote

Wonderful!!!  So, how's the economy?  

Precedent measurements were to find the odometer % error.

I also monitored with precision the whole trip fuel consumption:
(calculation in metric units):
· Traveled odometer = 355.3 km
· So real total distance = 353 km
· Fuel for this distance = 62.3 L
· Fuel ratio = 62.3L/353km
= 17.53 L/100km
= 13.33 mpg !!

Big Bro used to drink around +/-10mpg for the last 30 years.
Tune up + new road tires = just under 12mpg.
Jumped to 13.33mpg with Vacuum Advance!

[Gary Lewis]

I'm not at all surprised.  However, Big Blue can do 13.0 MPG, and I'm confident I could get more if I were to feed it manually instead of with the speed control.  So I think there's more to be had with Big Bro.

Do you have the advance set to 10 BTDC?  If so I'd turn it up to 12 and give that a try before you hit the road.  Listen closely for pinging at part throttle at low RPM.  And watch for kick back on starting, meaning it is hard to start.

[BigBrother-84]

Gary Lewis wrote

Do you have the advance set to 10 BTDC?  If so I'd turn it up to 12 and give that a try before you hit the road.

Yes, I set it up 10.
I will change it to 12 and test it

[BigBrother-84]

I recently installed a NOS speedometer with odometer (thanks to Gary!).

Big Brother’s original speedo was without odo/tripo.  It was driven by a 7 Tooth Drive Gear + 18 Tooth Driven Gear.
Last year I installed a used speedo with tripo, but it almost instantly ruined the gears (it was blocking).
So, I installed a NOS speedo without tripo, for Big Brother’s Big Tour.  For this one I installed a 6 Tooth Drive Gear + 16 Tooth Driven gear, that I had and found enough accurate for the speed needs.

But now, with this NOS speedo+tripo, I found that the odometer was not accurate, it was showing a little more than real mileage (+0,6%).

Since I had on hand some gears, I installed back new “original gears team” 7T + 18T.
Wasn’t satisfied, so I replaced the Driven Gear for a 19 Tooth.
Sounds good, even not perfect, now showing a little less than real mileage (-0,9%).

Since the perfect gears mix doesn’t exist, I’ll keep this combination (Big Bro will be aging a bit slower ).

Note that with this 7T+19T team, speedo is showing 5km/h less than real speed, for all speeds.
I’ll not fool around and will simply pull out the needle and push it back at the right angle.

[Gary Lewis]

I’ve not pulled new gears apart after just a little usage, but I’ve also not seen gears that are very worn even after lots of use. My guess is that your cable(s) are dry or kinked.

Cables are cheap to replace, but I’d start with lubing them before replacing.

[BigBrother-84]

I already have one on hand (cable).  I was just too lazy to change it...


Next weekend I'll do it.  Less complicated than replacing a Drive Gear and cheaper than a Drive Gear + an axle Seal.