muddinrc4life

i was running my savage at my local track yesterday and all of a sudden i relized i never got to second gear(it was perfect the first hour or so of running).
i dont know whats wrong with it. nothing seems to be broken. Please help me!

shanty140

The first thing I would do it make sure the shift point didn't get change some how. Mess around with the shift screw to see whats up. If that doesn't work, do a tear down of the tranny and take a look, it nothing seems wrong, put it back together and see how it how it goes. If that didn't do anything, well, time for three speed.

-SomeGuy-

It could be jumping straight into second or not shifting at all. Drive very slowly and slowly increase speed, listen to see if it shifts before you get to full speed. Find out if its shifting or not and adjust accordingly before you start taking anything apart.

Argess

I had this happen once.....jumped from 1st to 3rd and missed 2. Shift point spring had changed a bit.

Anyway, it’s a real pain to adjust the 1-2 shift as you have to take the tranny apart. In fact, the 2-3 shift isn’t exactly fun in the field as it’s fiddly. So I came up with another method. I’ll rehash it here, and then go farther with some actual numbers.

What I wound up doing was to take the tranny shaft with the gears and shift dogs in it, and chuck it in a drill press (largest gear towards the chuck, if I remember correctly). There's not a lot of shaft to put in the chuck, so make sure it is tight and wear safety glasses. Increase the speed of the drill press until you it makes the shifts you want. Start out slow and gently hold the bottom two gears (they won't spin when you hold them). As the drill-press speeds up, they will engage and start spinning, so be gentle holding them. By calculation, a good place to start, is to set the 1-2 shift for 3362 rpm range and the 2-3 shift around 5791 rpm.

I had to change speeds using belts, so all I could do was make sure it didn't shift at one speed lower, and did at the next higher available speed. A variable speed would work better, but you'd need a tach (airplane infra-red type, for example) or a stroboscope (maybe borrow one from the local high school physics dept.) to check the rpms. (A metal lathe might work better than a drill press). Keep a record (I didn't ... sigh) and then you can adjust up or down from there if you have to make another change.

Now, if a person was to take a perfectly shifting tranny apart, check it out on a variable speed drill press, and note the shift rpm (using a laser tach or a stroboscope), a person could get things working close to optimum first time by using those figures. But I haven’t done that. So where did I get the rpm numbers above? I calculated them three different ways and used the method I like best. Here goes:

Preliminary Data:

1st gear: spur to wheel ratio of 8 (based on rolling the truck one tire revolution and counting spur gear revolutions.

2nd gear: Spur/Wheel ration of 6.39 (based on 18/44 first gear ratio and 21/41 second gear ratio)

3rd gear: Spur/Wheel ratio of 5.18 (based on 18/44 first gear ratio and 24/38 third gear ratio)

1-2 shift engine rpm reduction (assuming no wheelspin during shift) is 20.1%

2-3 shift engine rpm reduction (assuming no wheelspin during shift) is 18.9%

CB/Spur ratio is 17/47 or 0.361

Peak Horsepower is at 28,000 rpm (for OS 30VG)

Peak RPM is 36,000 rpm (for OS 30VG)

Tire Circumference measured at 18.5 inches (does not allow for ballooning at speed)

First 3-Speed Adjustment for Max Performance

This method accepts the fact that you always want to shift around max horsepower (which I don’t like, but is a bona-fide test with full-size cars).

So for shifting around 28,000 rpm, we want the 1-2 shift to occur at ½ of the 20.1% change, which is at 31128 rpm. The 2-3 shift to occur at ½ of the 18.9% change which works out to 30922 rpm.

This translates through our tranny ratios to having 2nd gear kick in at an intermediate shaft speed of 4597 rpm and later having 3rd gear engage at a shaft speed of 5717 rpm.

If you do this, your engine will hit the screaming mark for every shift. Personally I don’t like that.

Second 3-Speed Adjustment for Max Performance

This method says to shift when you hit max horsepower at 28000 rpm.

Multiplying 28000 by the CB/Spur ratio and the 1st gear ratio, we should adjust the 1-2 shift for 4135 rpm. Similarly , the 2-3 shift should be adjusted for 5177 rpm, (using the 2nd gear ratio). These are earlier shifts than the above method and will probably work quite well.

3-Speed Adjustment for Max Fun

Let’s suppose we want the truck to shift at certain speeds (mph) vs max engine power. For a max engine rpm (36000) we can calculate the vehicle speed at 43.9 mph. Now let’s say the truck goes about 5 mph when the clutch is engaged. We have a total speed range of 38.9 mph to work with. Now let’s have the 2 shifts spaced equally apart (13 mph spacing). This works out to a 1-2 shift at 18 mph and the 2-3 shift at 31 mph.

At 18 mph, the tire rpm is 1027 and the 1-2 shift can be adjusted for a shaft speed of 3362 rpm (the engine will be at 22759 rpm).

At 31 mph, the tire rpm is 1769 and the 2-3 shift can be adjusted for a shaft speed of 5791 rpm (engine speed will be at 31313 rpm).

This last method is the numbers I would start with.

PS: Please note, this is an exercise only, and generates a starting point for anyone wanting to develop “best� shift points for a certain engine, CB/Spur ratio, tire size, etc.

youie

Damn thats one long post. Dont get me wrong, not doubting it, its just that its going to take some time to read and absorb.

rclugnut10

My Feedback: (1)

mine might be having the same problem i haven't opened it up in a while, and i had adjusted it to shift ealier, by half a turn, i rember it being very noticible, but now it seems quiet but the truck's acceleration does pick up a bit, any help, i still havent leaned it out too much haveing too much fun "testing" needle settings

rclugnt10

Knightfall

According to that popular YouTube video about setting up your trans if your trans ****s too late, or not at all you're supposed to adjust the screw (anti-clockwise, 90 degrees) within. Mine stopped shifting for whatever reason too. I made these adjustments, but never got it back out yet to see how it works.

http://www.youtube.com/watch?v=w5mzv...43689&index=11

jackrobinson

Ok. Had exactly the same problem. Only that it shifted but the moment I hit full throttle, it swung back into first gear.

This is all you need to do.

open the tranny and take out the gear set. DO NOT take it apart.

Unscrew the adjusting screw and you shall see a spring followed by a roller ball. Slightly tug the spring, lengthen it a bit. Clean out the tranny with WD40 and spray compressed air and dry it off.

Put back the ball, then the spring and then the screw. Then adjust the gear change. Thats it. You're sure to solve the problem.

savaged_dude

Are you sure you are still in tune? Hold the truck off the ground, this way thier is no resistance. Give it about 1/2 to 3/4 throttle and listen to see if it shifts. I would label out the tune first thing.

brett65

My Feedback: (18)

Mine stopped shifting, and come to find out that the little gear catcher had gotten stuck somehow, and caused something to grind against the inside of the case. It was junk, you can get a brand new x model 2speed for 23 buck on ebay.

cheiro

Hi,

Is your engine tuned right... not running too rich?? If it is try leaning it slightly.

rclugnut10

My Feedback: (1)

i know mines uber rich, i just tune it a wee bit and start to have too much fun with it before i can get it tuned to max, so it slow gets thier

rclugnut10