Shifter, FOC & Tranny Troubles

OK, this is the most commonly posted topic out there. Sooner or later virtually everyone will have trouble with the tranny not shifting into second gear, or not shifting from forward to reverse (assuming you still use reverse). Also, installation of the FOC (forward-only conversion) gives folks a hard time as the instructions and pics included with the FOC kit are often incorrect.

 This page is kinda long, so just click a link below to get to the area of the page that you need help with:

1)       2-speed shifter issues

2)       Forward/reverse shifting issues

3)       FOC Installation Issues

TECH NOTES: When you take the tranny out and apart, keep track of all small pieces, they get lost easy. Be sure and use plenty of medium loctite when re-assembling the CV joints. Use something like white lithium grease to coat gears. Check all the bearings while you're in there to make sure they are smooth and tight.

2-speed shifter issues

OK,  your MGT is not shifting from first to second gear. WHAT could be the problem, you ask? First off, start by looking at some of the basics.........

Most times, not shifting from 1st to 2nd gear is due to improper engine tuning, but it could something else. Here's a good page on tuning for power: http://www.rchobbies.org/cars_eng-tuning.htm 
Make sure your tune is good before proceeding.

1. Did you set the CB/spur gear mesh between the gears correctly? If they are too tight, then it won't rev up.

2. Is the clutch nice and clean? You mighta got oil on it when you had the engine out and it's now slipping.

3. Is your exhaust all nice and tight? If it's loose, the backpressure won't build and make power when it comes "on the pipe".

4. Is your carb linkage working properly? Take the air filter off and work the throttle trigger on the TX with engine off. You should be able to see the carb opening all the way.

5. Tune the engine? You usually need to re-tune a little between day-to-day running.

6. Loose slipper? If the slipper is too loose, well..........

7. Have you messed up the adjuster screw, or perhaps loosened the wrong screw?

8. Is the brake dragging?
   
   It is most likely one of those things above. But if it's not one of those things, then read on, the solution is at hand here, guaranteed.

Tighten the slipper ALL the way, just to be sure and eliminate that possibility. Next, make sure there are no loose wheel nuts or stripped wheel hexes. Also, I would take the clutch apart and make sure it is in good working order, nice and clean with good bearings. Once in a great while there is something wrong in tranny too.

Assuming you are tuned and making good power, and that you've checked the above items, then I would recommend you try adjusting the black screw in increments of half-turn. If you end up going more than two full turns and still get no results, then it's probably time to yank the tranny and check inside. It's tough to see the screw. Use a good flashlight to look in there and make sure you are moving the correct screw.

Taking the tranny out is no big deal. If you've never done it, then now is a good time to learn. Get a digital camera and take pics as you remove pieces, that way you'll have something to remind you how it all goes back together. Dis-assemble the tranny and eventually you'll get to the shifter. Here's a pic:

There's a small spring-loaded arm on the underside of the shifter (see pic below). Make sure it is completely free and not sticking. Adjust the black screw so there is a small amount of effort required to move the spring. There's a pic below which shows the adjuster screw in place, with about one thread exposed. This is a good starting point and will almost always be very close to optimum shift point.

Also, make sure the silver set screw is TIGHT (and set on the flat spot of the shaft) and use some loctite if it has been loosened. If it has been loosened by mistake, then the shifter will never shift.

Use the black screw to adjust the shift point.

Some guys (including me, actually) THINK they are turning the black screw, when actually it is just the friction of the driver tip in the hole. In other words, they never really turned the screw at all, LOL. Just a thought.

Typically, a shifting issue involves tuning. The engine is not making enough power. If you go through the procedures in this section, then you should be shifting just fine.

Forward/reverse shifting issues

If your tranny is not shifting from forward to reverse (or vice versa) properly, start by looking at the servo and linkage.

1. Make sure the shifter servo is good and strong
2. Work the shifter back and forth using your radio to test
3. Make sure you have a fully charged battery pack
4. If you're using all stock parts, then do the Channel 4 Mod
5. Make sure the linkage is all in good order and adjusted correctly

If all those items are good, then you may need to take the tranny apart and look around. Take the shifter mechanism apart and make sure there is no bent or binding parts. Fixing a forward/reverse shifting problem is usually rather easy, so just take your time and look around. You'll get it.

Below is a pic of the forward/reverse shifting mechanism:


The big round piece is called a clutch assembly, although I think the term is a little misleading. Personally, I think it should be called something like "shift safety mechanism". Regardless, the clutch refers to the two spring-loaded arms, similar to shift-point arms. These arms come out at a rather low RPM and contact a collar inside the clutch assembly. This prevents you from switching from forward to reverse at high speed. At lower RPM's the arms reside in their slots (as shown in pic below) and allow the clutch assembly to slide between forward and reverse. It's a direct drive assembly, with no slippage.

The forward/reverse shifting mechanism is a very straightforward piece of gear.  The piece simply slides forward and back, so something may be preventing it. Just look around carefully and you'll be able to figure it out.

Everything should rotate nice and smooth. If it does, then put the engine in and let her rip!

If you have any questions on any of these tranny issues, just email: Chevy-SS or Junior