How long did each of the rebuilts last? You might want to get a "remanufactured" transmission put in, instead of "rebulding" the existing transmission. You may have warped shafts in there if the casing was affected. Otherwise the rebuild shouldn't be that difficult, it's not like a GM 4T60 kinda tranny some talked about getting right.
Is that a A340 or A440 series transmisson. The Toyota A340 seems to have a lot of problems, therefore I'd get a good "reman" that usually comes with a 3 year/75K-mile or more warranty. I haven't used Jasper Engine but you might want to check out their 3yr/100K-mile warranty on their "reman" transmissions. Jasper is one I'd consider if I don't rebuild my own (but not sure if your A340/440 model is avaialbe there, so check with them):
Hi 93 4runner; I've had the transmission overhauled twice, this is the third
> time now and the mechanic is saying that he thinks the housing is the prob
> because he is seeing filings in the fluid after he drained it. He was
> opening the trans again citing a lack of performance on the road test..
> Does this sound right; that after an overhaul the housing would have
> something to do with these filings or is it something he did wrong in the > overhaul..
> Can the housing itself be bad (as in worn, not cracked) as to be > unservicable?
> tia
> req