1997 Oldsmobile Bravada transmission/shift linkage problem
 

Ok, so I bought this truck in May of this year. I've put front wheel bearings, front shocks, new windsheild, new cat and muffler, new tires, new ball joints, new idler arm, and many more things on it. I am the type of person that likes to gear down the transmission when going down a hill, so I don't have to use the brakes as much. I go about 40, then shift it down into second gear. Well, a couple months ago I was driving around in the rain, and it worked fine for most of my trip, then heading home, I noticed it wouldn't shift down into ANY of the gears. Park, Neutral, and reverse work fine, but in OD, if I start from a stop on a hill, when it gets to the RPM's it's supposed to shift at, it acts like it's running crappy, I guess you would call it hesistation to shift because it's running fine. Also, when I'm driving, if I've got my foot slightly on the gas and going down a hill, you can feel a jerking feeling, like a real bumpy road, then it will kick out of OD until you park it for a few mins off. If you shift it down and hit the gas, it shifts down, when it's at about 3k rpm's, but does the hesitation type feeling like I said above, in all the gears. I'm wondering if my shifter linkage is a little off because when you shift it down while coasting, it acts like you shifted it into neutral. Could it be between gears and not fully engaging until I hit the gas? I just had the fluid changed, not flushed, and it shifts more responsively, but no change to the rest of the problems. Any help would be greatly appreciated, and sorry for the long post

manual transmission, right??

No, it is an automatic. The shop that did the fluid and filter change said whoever serviced the tranny last used silicone on the pan, and it sucked it into the filter. I dont think it's failing, because it doesnt do the hesitating all the time, although, it does shudder and kick out of OD anytime around 60mph. It has 170,000 miles on it, and service records for years...

Ok, stupid question... Would an oxygen sensor thats been bad for quite some time do this shuddering and what I call hesitation? Bank 1 sensor 3 (The one right after the cat) has been bad for a while, and the problem that I've been thinking was the transmission has been getting progressively worse... It runs fine for the most part, and these problems are not cosistant...

Downstream O2 sensors are catalyst monitors only and do not impact engine performance.

Have you connected your truck to a scan tool to see if there are any active or pending codes that might give direction to your diagnosis?

I took it to advance auto yesterday and it had two codes, one was bank 1 sensor 3 low voltage, the other was bank1 sensor 3 faulty heater. Would their cheap machine show transmission codes? I know when my ABS sensor went bad, I took it to them to check the codes, and only the o2 sensor came up. Had to take it to a garage, and they did it free, and told me exactly which one it was. I am going to replace the o2 sensor today, just to see if the SES goes off, and if it doesnt, then I'll take it to a garate. Have you ever used seafoam trans tune? was wondering if I would have to get my fluid changed again if i used it?

The only transmission additive that I have used in the past is Lucas Transfix. It worked good at freeing up a sticking check valve in the trans on my old Ram. Haven't had a reason to use it since then though.

Arg. I'm completely baffled. I've already put between two and three grand into this thing since May. The shop didnt even notice the problems i was talking about... I live up here in Maine, so the closest transmission shop I know of is about 40minutes away. I guess I'll try the sea foam. Is there any vacuum hoses that go to the tranny?

You don't use vacuum lines when adding additives to a transmission like you would when using seafoam treatments on the engine. You just dump them down the dip stick tube.

I was just wondering if i had a vacuum line popped off or something could that cause my problems? I dont even know if the trans uses vacuum lol