>From your description I assume you have modified the cam under the gearbox
top as this is the only way to get overdrive in second. However you are
putting a huge strain on the unit if you put your foot down hard in second
overdrive, possibly more than enough to cause it to pop out particularly if
the it is a 75-78 type with early relief valve with even lower pressure than
intended. Does it tend to come back into overdrive when you lift off a bit?
In any case it would probably benefit from higher operating pressure - it
isn't easy to get a lot more from the early valves - the later ones can be
easily pushed up with some thin shims.
John Kipping
----- Original Message -----
From: "Susan Kahler" <spitfiresuz@141.com>
To: <fot@autox.team.net>
Sent: Monday, April 05, 2004 3:28 PM
Subject: O/D troubleshooting help needed - Hallett report at end
> Hi all!
>
> Again, just back from Hallett, and before I collapse for the evening
> after a most EXCELLENT weekend, I have a transmission question to ask.
>
> What would make a J-type single-rail O/D transmission with correct
> amount of fluid and snug electrical connections drop out of 2nd O/D into
> 2nd in a hard left-hand turn? This happened a couple times this
> weekend, and none of us could figure it out. Each time it happened I
> had driven about 4 laps with no trouble (1.8-mile technical track with
> lots of elevation changes). On about the 5th lap, I drive hard down the
> straight after Turn 1 in 3rd O/D. I brake HARD and downshift to 2nd O/D
> while off the gas to get set up for Turn 2, a HARD left-hander that
> opens into a small ess curve before a short uphill straight. I modulate
> the throttle through 2 and get back on the gas hard as I am
> straightening out and heading into Turn 3 (the small ess). When I get
> back onto the gas at this point it drops into straight 2nd gear and then
> upshifts itself back to 2nd O/D. I have not changed driving style,
> line or anything in this lap compared to my other laps.
>
> 2nd O/D did NOT ever do this going through the completion of The Bitch
> (barrel over a blind hill in 3rd O/D, brake HARD and downshift to 2nd
> O/D at the same time, then get back on the gas hard to get up the hill
> onto the back straight).
>
> Could this be some wierd combination of hard left cornering, fluid
> pressure dynamics, and heat, or am I missing something? We were going
> to try Larry's pressure gauge on the O/D, but the frame rail was in the
> way and we only had one race left so we didn't worry about it and I just
> straight-shifted through the corner. (We will pressure-check it before
> our next event for sure.) This O/D box has not been modified for
> racing, so I am thinking there is probably something we need to do to it
> to optimize racing performance. There is no leakage from the box or
> the tranny.
>
> Hallett Report!
> ****************************
> BTW, I had my best lap time at Hallett this weekend, a 1.39! Larry's
> best time of the weekend was a 1.37, and he was thrilled as well (he may
> have done even better, since we left before we could have heard times
> from the last Group 4 race)! He gave a big Healey and a couple very
> nice MGA's quite a run, and always stayed in the front! It was a joy to
> watch him increase his lead lap after lap! The car and driver are
> performing VERY well.
>
> Dan Duryea came over from Colorado, and this guy has guts! He lost a
> wheel due to an axle failure in one race, and had the axle replaced and
> the car back on track for his very next race! Fortunately, there was
> no real damage to the car except for flattening the bottom of his
> exhaust tip, with no change to the inside diameter. Amazing. And Joe
> Hovey was there with his green Spitfire, and did himself proud by
> learning a difficult track and then proceeding to progressively decrease
> his time with each run. Fun was had by all!
>
> Thanks for any help on the O/D problem in advance!
>
> Keep Triumphing,
> Susan :)
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