Transmission question - 99 Rodeo

2 parter here.

I've been traveling lately and leaving the Rodeo in the garage for several days. When I get back and start driving, there is a noticeable jump in the tran between 1st and 2nd. This usually last the entire drive to work, about 12 miles. When I leave work, the problem is not apparent and doesn't reappear until I go on another trip. What gives with this, any ideas?

Also I read that the trans fluid should be changed at 60,000 and I'm sitting at 64,000. I called my shop and they claim there are several Rodeos that they cannot do this to due to design circumstances? Anyone else run into this with a V6 automatic '99?

Thanks,
KB

Your rodeo has no transmission dipstick- but is totally serviceable. The ATF in these trucks should be changed out every 30Kmi, these 4L30E trannys are tough on ATF. There is a fill/level check plug & a drain plug located on the main (large) tranny pan. ATF has to be pumped up thru the fill plug. Take your truck to a reputable shop, have the tranny fluid exchanged through the cooler lines & pan dropped & the filter changed. G/luck
Joel