Re: Checking transmission fluid

Posted by BH On 2011/9/20 17:50:45

HH56 -

For some reason, I thought the OE cap might be a simple friction fit (with an o-ring seal) to the fill tube, I was wrong. SC Vol. 23, No. 9 advises:

Quote:
Looking more closely at the illustration just below that text, the top of the fill tube reminds me of the neck for a radiator cap. That style doesn't seem to lend itself for turning a replacement cap on lathe.

Not sure how the OE fill tube is fitted to the Ultra case - not sure if anyone would wanna go quite that far with an adaptation, anyway.

As for using a threaded bushing (i.e., a bulkhead fitting) in a cap, if you wanna use a GM dipstick tube and seal, then that bushing/fitting should only be as long as the THM case is thick, and its I.D. needs to be same as that of the hole in the THM case. (That is, you're gonna have to also examine a GM THM tranny.) IIRC, when the (swedged) bottom end of the dipstick tube is pushed through that bushing-type seal, the side wall of the seal is pushed outward, to establish a seal against the case as well as the tube. BTW, that seal is commonly found on the shelf of most any GM dealer if you want one for inspection.

I don't think rebending the dipstick tube is gonna be a problem; there may be some good old tricks we can try for that.

Yes, the goal should be to have a near-stock appearance, yet be completely reversible to original. Now, if only we could find an GM dipstick with the old-timey handle.