Converter drainback

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gliderider06

gliderider06

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Question... my 69 Dart, 360/727 B&M holeshot 2500 converter combo that when it sits, a week or so, the converter will drain. I have to put it in drive and bring the rpm's up to about 1800 (with the brakes on) to pump it back up before it will move. If I don't do this, it will not move, especially in reverse for some time. I can drive it all day let it sit for several hours and no problems. The trans has about 4,000 miles on it since rebuilt. Shifts hard and strong, no slippage other than after it sits a while. This is the second converter in it. It did have a 3500 converter, but I changed it to the current one and it did the same thing with the 9" converter also. I thought it was the trait of the little converter and didn't think much of it until now.
Any thoughts? I was thinking of the transgo-tfsc kit that is supposed to eliminate converter drainback. Is this what the kit is describing?
 
There is a new design manual valve with a few other small parts to cure this. It also allows you to check fluid level in park. The newer kits usually already have this upgrade.

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You can tell if this mod has already been done by looking at where the manual valve enters the valve body casting. It will either have a slot filed across the opening or be countersunk.
 
Start it in neutral after it sits for awhile it will fill up fairly fast
 
One common problem with why they drain back even after their rebuilt is there is wear on the pump stator. Even with new sealing rings it lets fluid drain back. Doesn't take much wear either. They've come out with a thicker set of Teflon sealing rings for the 904 that work well to seal up the stator better. Used them in the 904 in my Cuda and it's the first one I've done in quite a while that has no drainback issues at all. Let it set a week and start it, throw it in gear and go. The older Trans-go kits addressed the issue with a modified manual valve and by having you drill a small hole (1/16" if I remember right) through a casting. It helps but as you can imagine it takes quite a while to fill a converter through a 1/16" diameter hole. I haven't used any but have heard the newer kits use a totally different manual valve that is much more effective. As Jimmy said just start it in neutral and give it some time and it'll fill up just as quick as it does in drive and it's easier on the converter.
 
Awesome! Thanks guys for the info. Maybe i'll drop the pan at some point and put one of those kits in it.
 
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