[rgunderm]

rgunderm,
Did you ever get a resolution to this?  I have a 1988 with this transmission and it is slipping since my last tranny oil change.  I don't think the modulator was changed.
Thanks,
Mark

Hi Mark.The resolution for me was that I realized I have an HT741 instead of an HT740. HT 741 was the first year of complete electronic shift so the modulator was eliminated. In your case, if it’s slipping after fluid change, I’d verify the correct fluid was used and that level is correct. Next, I’d verify pressure to the modulator, then replace the modulator as I understand they failed often.