Re: Ultramatic trap door

Posted by Don Shields On 2012/10/11 0:47:25

Responding to Howard's request, here are all the dimensions in inches:

The galvanized cover or door is 6 1/4" high X 9" wide. The door is clearly oversized but it also covers a hole nominally 1" X 1 1/4", visible in the second photo. Note there is also a 3" X 3 1/2" riveted panel visible in the upper right of the first photo, probably concealing yet another hole. I think all these holes, including the dipstick access, were originally cut to access the bell housing mounting bolts (you can see the hex head in the smaller hole that the door covers.) I don't know why this was done, maybe they had no shop manual?

The dipstick access opening measures 5" high at the gas pedal side tapering irregularly to about 4" high X 6" wide. This opening is located 8 1/2" below the base of the stitched horizontal seam in the black inner firewall cover pad. This opening begins about 2 5/8" up from the toeboard floor level under the gas pedal.

If you are thinking of making an opening like this, I would suggest making it smaller than this one, just large enough to comfortably fit your hand into it. That should also be large enough for a funnel when refilling the transmission. As seen in the third photo, the dipstick cap is located under the lower left corner of this opening. I would try to center the opening over the cap a little better than this if possible. Of course if this one was centered over the cap it might require some complicated bends in the door where it would be covering part of the lower hump area and carpet modifications to get access to the door. I hope this is helpful.

To respond to Tim's comments, yes the opening is larger than it needs to be for the dipstick; keep in mind they seemed to be trying to get to the housing bolts first and may have enlarged it to get to the dipstick as an afterthought. Overall, I think the benefits of this modification outweigh its detriments.

The transmission was completely rebuilt by the prior owner. It leaks very little, not nearly enough to justify a reseal.