I wrote an article recently about adjusting diesel automatics. The point to much of the adjustments was to compensate for internal leaks that change the rate of filling of clutch packs and band servos. (The article is not yet in print but I noticed that it is archived already for those that read such things: http://www.babcox.com/editorial/ic/ic20242.htm
The point is that all the rubber in the trans is the same age and in your case all at the point of causing trouble. We advise resealing and rebuilding anytime the car has over 150k. But, that is mostly due to labor costs. Resealing the front of the trans is 9 billable hours that is a little over half the labor to do everything; not practical if labor has value.