'98 Jimmy Shift Problem
#1
12-17-2009, 10:30 PM
'98 Jimmy Shift Problem
I just bought a 1998 Jimmy. I was told it needed a transmission so I expected to either rebuild it or replace it. I got such a great deal on it I barely test drove it and just assumed the worst but now that I've driven it a bit I'm not so sure. Here are the symptoms:
It engages in Drive or Reverse just fine. It might be a little sluggish in Reverse but it takes off just fine in Drive. It shifts into 2nd just like it should and still has plenty of power.
Then, as I continue to speed up it suddenly acts like I stomped the throttle and downshifts. If I let off it stays in the lower gear but if I keep accellerating it seems to shift another gear and continues on but it's not normal because the RPMs seem to high. At 45mph I think the RPM was around 3500 but I didn't really pay that much attention to the numbers. It just felt like it was working too much.
At this point if I shift from Drive to 3rd, which I believe is actually from Overdrive to Drive, the RPMs jump up like it did when it downshifted so it's like it's in a lower gear but Overdrive is still kicking in.
If I tap the brake I notice no difference in RPM so I assume the torque converter is not locking.
On the way home I stopped by AutoZone and had them pull the codes but there weren't any at all. I'm upgrading from a '92 S10 Blazer so I'm not that familiar with OBD-II yet but I assume the codes can be checked with a normal reader? Or do you need to do something special to get tranny codes? The clerk at AutoZone had no idea.
After I got it home I checked a few things and found that the transmission fluid was low enough that it didn't register on the dipstick. It took about 3 quarts to top it off and I hoped that would at least make a difference but when I test drove it the symptoms hadn't changed at all. Except that maybe Reverse doesn't seem so sluggish.
Any ideas? I've rebuilt a couple of older automatics so I have no problems with tackling it but since this one is electrically controlled I'd hate to think it's something simple that will still be screwed up after I rebuild the tranny itself.
Any help would be greatly appreciated!
It engages in Drive or Reverse just fine. It might be a little sluggish in Reverse but it takes off just fine in Drive. It shifts into 2nd just like it should and still has plenty of power.
Then, as I continue to speed up it suddenly acts like I stomped the throttle and downshifts. If I let off it stays in the lower gear but if I keep accellerating it seems to shift another gear and continues on but it's not normal because the RPMs seem to high. At 45mph I think the RPM was around 3500 but I didn't really pay that much attention to the numbers. It just felt like it was working too much.
At this point if I shift from Drive to 3rd, which I believe is actually from Overdrive to Drive, the RPMs jump up like it did when it downshifted so it's like it's in a lower gear but Overdrive is still kicking in.
If I tap the brake I notice no difference in RPM so I assume the torque converter is not locking.
On the way home I stopped by AutoZone and had them pull the codes but there weren't any at all. I'm upgrading from a '92 S10 Blazer so I'm not that familiar with OBD-II yet but I assume the codes can be checked with a normal reader? Or do you need to do something special to get tranny codes? The clerk at AutoZone had no idea.
After I got it home I checked a few things and found that the transmission fluid was low enough that it didn't register on the dipstick. It took about 3 quarts to top it off and I hoped that would at least make a difference but when I test drove it the symptoms hadn't changed at all. Except that maybe Reverse doesn't seem so sluggish.
Any ideas? I've rebuilt a couple of older automatics so I have no problems with tackling it but since this one is electrically controlled I'd hate to think it's something simple that will still be screwed up after I rebuild the tranny itself.
Any help would be greatly appreciated!
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swdockter
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03-27-2007 09:40 AM
