700R-4 Overdrive Downshifting

[4pilgrim4]

I own an 83 Jimmy "trailering special" with a 6.2 liter diesel turbo'd with a Banks sidewinder, axle ratio 3.73 and normally run 235-75 x 15 rubber. I also tow a 16ft Scamp fiberglass camper trailer weighing around 2500 lb.

Several years ago the automatic went out near Los Angeles. I dropped the pan beside the road cleaned out all the debris including torrington bearing parts I could, put in a new filter and refilled it with ATF. It limped, but I got into Pomona and had it rebuilt at a great little shop that specializes in rock climbers. All the hard parts including the case were toast, but the clutches still looked like new.

The fellow did some upgrades (not exactly sure what) and said I could tow in overdrive. All is fine and it has gone about 50K without any problem. However, whenever I give it more than about 1/4 to 1/2 throttle it downshifts especially from OD down to 3rd. This doesn't allow the diesel to develop much power as I would like.

My question is -- Was this done to make the 700R-4 withstand the power and torque of a diesel? If so, is there another solution -- possibly by using upgraded hard parts that would allow full or nearly full throttle operation?

The reason I ask, is I am in a financial position where I could dispose of my older GM trucks and upgrade to a new or newer vehicle. Or, more economically I could upgrade the ones I have eliminating the nuisance factors such as the overly sensitive downshifting 700R-4.

Ideally, all that is required is a minor adjustment, however I am not interested in going this route if the result would be decreased reliability. If it would take a full blown overhaul with gold plated parts, that would factor into my decision, but I think I would still be money ahead and then some.

Any good words of advice?