904 wont hold first gear

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Auzdart

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I rebuilt my 904 for performance and fitted a Transgo TF-2 kit. The car has a mild 360 but still has the stock convertor and 7 1/4 with 2.74 rear end.

The trans performs and shifts like stock. Soft shift to second, firm to third.
I assume this is because of the stock convertor and rear end. I expect there will be a change when I fit my 8 3/4 with 3.79 gears and high stall convertor.

My only concern is that I modded the trans with shift command feature and the trans does not hold in first gear. If I stat from a standing start in first it will shift to second as if I had selected second. Also it will not shift down to first when driving.

The mod has been done correctly as per instructions. I only ground down the 1-2 governor valve to .125". Should I have gone more? Is there something I my have missed?

Any help would be great.
 
The converter and rearend have very little to do with the performance of the trans. A high stall converter can soften the shifts some and a higher numerical gear set will lower the shift speeds and that's it.

Have you checked your shifter linkage? Even a stock 904 will stay in 1st until a very high rpm when you hold it down in low so I suspect either the shift linkage isn't really pulling the shift lever all the way down in low or something is put together wrong in the valve body. If you ground the governor valve down per the instructions it's fine.

Also don't forget that the throttle pressure linkage adjustment has a great deal to do with what speeds the trans shifts at, the shift firmness, and kickdown. I always start out with it adjusted to maximum then back off if needed to get the shift speeds where I like them.
 
Thanks Fishy, I was hoping you'd jump in. The shift linkage could be the problem, I never thought to check that.

As for the kick down linkage I just followed the instructions as per the owners manual, which said something like - to hold or wire the linkage forward and adjust so the throttle arm has a slight rearward pressure on the linkage. When I drive the car it will not kick back unless I have my hard to floor, this does not feel right.

When you say "I always start out with it adjusted to maximum then back off if needed to get the shift speeds where I like them."

Is maximum all the way forward on the trans arm?
Do you have a rule of thumb for shift points?
 
Maximum is all the way back on the trans lever. What I do is hook everything up and wire the throttle all the way back and adjust the throttle pressure linkage (or cable if that's what's on the car) so it's pulling the trans lever all the way back. Most of the time that'll work fine but sometimes you get one that you have to back off some if it's holding the shift speeds longer than you like. Depending on the engine combo and stall speed shift points can vary quite a bit so I don't have a rule of thumb. Just adjust it to shift where it feels good (not laboring or revving too hard) at low speeds and kickdown works.
 
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