Dogbox jumping out of 4th

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Dogbox jumping out of 4th

Postby mmacquee » Wed Jun 13, 2012 5:09 pm

Twice this past weekend my TRE gearbox popped out of 4th, both time in the same high-speed corner. Lost several positions by the time I was able to find agear again, itself an frustrating process. But it was in 4th enough that I was pulling hard for a couple hundred yars before it popped out (for those who know Summit Point, I hit 4th before the bridge, it popped out in the middle of turn 10, same place both times). Is it possible it was not fully engaged? Or does this mean the 3-4 dog ring is worn?
I have been running Redline lightweight shock-proof oil in it a/k/a Smurf blood - is this the best lube? Thanks -
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Re: Dogbox jumping out of 4th

Postby Sprite33 » Wed Jun 13, 2012 6:38 pm

My guess is the 4th gear dog ring is worn or the 4th gear cogs are worn. It could be engagement is not complete. You should be able to check engagement by taking off the side plate but dog ring and cogs will probably require transmission disassembly and close inspection. Either way the transmission will have to come out unless you have some unique access to it.
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Re: Dogbox jumping out of 4th

Postby mmacquee » Wed May 08, 2013 11:04 am

Mystery solved - the PO, who assured me that the box had been freshened up and had only a couple of races on it before I bought it, had mis-set the float on the counter-shaft. The Torrington bearings at each end had broken up. No damage to the cogs. I took the opportunity to replace the 1st, 2nd and 3rd gear sets with different ratios (1.77:1 instead of 1.66:1, 1.42:1 instead of 1.3:1, 1.22:1 instead of 1.17:1) and am happier with that result too. Gears are usually to be found on the Apexspeed site, where Formula Ford racers dispose of unwanted/surplus gear sets. Price was good for genuine Hewland - about 1/3 of the new price asked by Taylor or Pegasus.
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Re: Dogbox jumping out of 4th

Postby Sprite33 » Fri May 10, 2013 12:23 pm

Glad you solved the problem. As to gearing, this is what Huffaker recommends and has worked well for me. 1.68 - 1st, 1.38 - 2nd and 1.17 - 3rd. First gear is kind of tall for taking out from a stop but allows you to use all four gears on the track with a good spread of ratios when shifting. I have another set that I don't use very often but comes in handy for a track that has one or two very tight corners in addition to a very long straight or high speed oval. Those gears are 1.8, 1.48 and 1.22. They are the gears that my trans had when I bought it. No one seems to know what class that was use in nor why they selected that combination. Best guess was it was used in a 1275 FP car. Your new ratios look to be a decent setup too. As long as you are comfortable with them, they should work well.
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