This happened to me twice in the last 800 miles. Pull out of the drive way, go 700 feet. Get to a red light. When it's time to go it's like the damn thing is in neutral... (and it ain't...I checked)...I need to run through the gears a couple of times then I get engagement...any thoughts? o No:
Anytime you have a trans problem, first thing you should do is look at fluid level and condition. Is it pink, or dark brown? Can you see or feel any grit in the oil? Does it smell burnt? Second thing to check is the vacuum modulator. Does it have a leak free vacuum supply? Is there any ATF on the vacuum side of the modulator? Does the modulator hold vacuum?(test it with a mityvac or equivalent) Third thing to do is drop the pan and make sure the pickup/filter is secured correctly and not loose. Check those things and let us know. How many miles on the trans?
Hey Larry, Thanks. 48,000 miles..Nice and pink, no burnt smell, no oil by vaccum modulator (I may need to look at that one a little closer), it was low a quart so I topped it up (followed shop manual instructions)...How did it get low you ask? In Feb I did my pan gasket and overfilled my tranny (pints and quarts issue!!)...Which meant I had to shove a tube down the dip stick and extract...could I have knocked the filter out when I shoveed the tube down there?? (oh, and I did not change the o ring on the filter tube...). So will wait to see if trani acts up again. Does the modulator hold vacuum? I have a vaccum gauge...can I use that? Sorry Larry, limited tech smarts! I looked at the trani section in my manuel, I was somewhat intimidated!!
Go through what Larry suggested first to make sure you have the proper fluid level. Cold it should be 1/4" below the ADD mark. When driven about 20 minutes it should be at FULL. The full at normal operating temp is what you should go for as the 1/4" below add is just a guide to get you started. A bad modulator will give either very harsh or no drive/reverse as well as very early/late shift into 2nd. The modulator sense engine vacuum to set shift points. Low vacuum (heavy throttle) gives a later shift. Vacuum at idle is high and this will give a softer shift into drive or reverse. Most of the times, they go bad by leaking vacuum which will give you a harsh bang into gear. If you still have the old black can style modulator, it has a section that contains a "bellows". Without going into a whole discussion on them, they are basically a means of adjusting for altitude changes (mountain areas). In some cases, they go bad and soft shifts will result. It is doubtful that you knocked the filter out, but anything can happen. When it goes into neutral, will it go normally into reverse? If engagement into reverse is normal, but you still get no drive, it could be a band adjustment issue. As the band wears, the adjustment goes off and it can result in just what you have happening. It would have to be pretty far off, but is possible. Refer to the chassis manual, but there is an adjusting nut just behind the shift linkage on the drivers side of the trans. Loosten the nut and use an allen wrench of the correct size to tighten the adjuster all the way down snug. Then back it off exactly 4 turns, locking the nut so it doesn't change the setting. Do the basics first before worrying about anything more serious. The ST300 gets slammed a lot, but is still a very good trans. They even held up very well behind many a 401 Gran Sport. Scott
When ever you first install a trans/torque convertor, it is necessary to cycle the shifter through the gears several times to get the fluid all over the tranny. Which it sounds like you had to do twice now. So, yes, check the fluid. If it is full, then you might have a pump going bad. The front pump, I believe.
Yes, you could have knocked the filter off, but I think your problem would be worse had you done so. Yes, the modulator should hold vacuum. To check it, you will need a vacuum tester(pump) like a mityvac. They are sold in auto stores and Sears. Good for testing lots of vacuum controls on engines. Follow fireballs suggestions also.
Scott thanks for your comments as well, I will get to this in about 10 days or so...away on business. You asked about shifting issues...under hard acceleration it would slip a bit going into second, that was essentially the only complaint I would have had. Then twice in the last 200 miles, I would leave the house get to the corner on a stop or a red and it was like it was in neutral, no reverse no drive...If I ran the shifter through the gears once or twice boom it would kick in and function like all is well. I have been wanting to check my low band adjustment for a while...I will give that a shot as well as the other items you and Larry mentionned.
Michel - If you were a quart low that was most likely the problem. You should not have any more issues. See how it runs and if it acts funny again pull the pan and check the filter. Nice car! - Bill
when checking the band adjustment the tightening spec is 40 inch pounds then back off 4 turns. my st 300 had a broken band which caused a lot of slipping at first then it would lock and go. also the bands are getting tough to find. went through this when i rebuilt mine this past spring.
