Re: [Amc-list] clutch questions

[Frank Swygert <farna@xxxxxxx>]

You MUST get that kick-down switch working! I know the Twin-Stick system 
is more complicated, with electric and vacuum switches. If you need help 
trouble shooting let me know. I've had to trouble shoot one TS system, 
but that was years ago. I've repaired several standard ODs though. The 
most common problem is burnt contact points in the governor and the 
solenoid itself. Pull the covers and clean the points -- they look just 
like ignition contact points on the tips. The relay may have the same 
problem. Look over the wiring good and you can figure out how to use a 
standard relay. I used a horn relay on mine once because the OD relays 
are no longer available. Even one of the new Bosh style square relays 
will work fine -- I used a horn relay because I wanted the old fashion 
metal can type. The only real difference is the OD relay has a fuse 
mounted to it. Easy enough to use an in-line fuse instead.

If the TS kick-down is working right, it will be much easier to shift as 
designed (1-2-2+OD-3-3+OD). That's why the button is on the shift lever 
-- so you put your hand over it when you shift, palm on top of the 
button, so it automatically kicks down when you shift up or down.

On all the Borg-Warner overdrive units the kick-down switch is a must! 
What it does is momentarily ground the coil so the engine skips 1-2 
firing cycles. This takes torque of the trans when the down-shift occurs 
since the engine is just "coasting" those 2-4 revolutions. That's just 
enough to take the load off the trans while it down-shifts. If you don't 
like the coil being grounded you can wire in a relay to cut power to the 
coil instead. I did that when I ran one behind an EFI 4.0L. I didn't 
think the computer and/or electronic ignition would like a momentary 
ground, so I put a relay in the power line to the ignition module. The 
OD circuit just tripped the relay momentarily, it was like quickly 
turning the switch off then back on. It's not off long enough to cause a 
backfire though.

If you don't cut the engine (or use the clutch) when it down-shifts it 
puts a strain/shock on the planetary gear shafts (which are small) when 
the shift suddenly occurs. Eventually one of the planetary gear shafts 
break from the strain/shock and the planetary gear binds inside the 
drum, locking it up. You don't lose the tranny, fortunately, just OD. It 
won't free-wheel either -- the output shaft and drum are locked together 
so it acts exactly like a standard three speed trans. I broke one years 
ago by not having a kick-down circuit and not using the clutch -- didn't 
know! Learn from my mistake, no need to make your own...

I'm pretty sure Tom knows some/all of this, but others may not!

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

_______________________________________________
Amc-list mailing list
Amc-list@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list