The_Magicians_Eye Posted October 16, 2012 Share Posted October 16, 2012 So I had my trans rebuilt by AAMCO in December of 2010 when I first bought my pathy. Now not even two years later I think it's about to go out!!! So ever since I got to NY I've noticed it shifting a little weird. Feels like it's not shifting into the proper gear at time or slipping the clutch rather than fully engaging. Things got worse over the weekend when I hooked up my 4x8 enclosed trailer and took off to go pickup an industrial sewing machine. The trailer was empty other than the sewing machine table (maybe 75 to 100 pounds at best). While driving home at around 65 the trans light came on. I slowed way down and it cooled off enough to turn the light off. I babied it home and parked it for awhile to let it fully cool off. Ever since then everything I listed above seems to be WAY worse. It's strange because I know the clutches aren't warn out. I know this because sometimes it shifts hard. It's like it's completely freaking out and not knowing how to shift. I can come to a complete stop for a split second at a stop sign and rather than shifting into 1st it stays in 2nd. So when I pull away from the stop sign it slips really bad. Or I have to manually shift it down a gear. Over drive seems to be slipping really bad too. Like it doesn't know if it should fully engage or not. Any ideas other than to get ready to buy another trans? Wondering if there is some sort of sensor that could be bad that is not talking to the trans computer properly. Link to comment Share on other sites More sharing options...
Towncivilian Posted October 16, 2012 Share Posted October 16, 2012 (edited) Have you changed the fluid since the rebuild? There's probably crud from the rebuild process as well as possible break-in wear of any new components floating around in the fluid, which is bad. Do you have an auxiliary in-line cooler and/or an in-line transmission filter? How does the fluid look and smell right now? Edited October 16, 2012 by Towncivilian Link to comment Share on other sites More sharing options...
The_Magicians_Eye Posted October 16, 2012 Author Share Posted October 16, 2012 No I haven't changed the fluid. I guess it makes since on why I should but they didn't tell be that I should so I figured it was good to go. I know they flushed the whole system a few times because they were worried about metal shaving in the lines from the damage that cause me to need to rebuild it in the first place. I don't know @!*% about transmissions much less these ones. Hell I don't even know what the trans computer looks like. I do have two external coolers because I don't use the stock cooler. The fluid looks as good as it did on day one. However since last weekend now it has a burnt smell. No inline trans filter. Link to comment Share on other sites More sharing options...
Towncivilian Posted October 16, 2012 Share Posted October 16, 2012 I'd suggest a full fluid exchange to begin with. You can do this in your driveway. You will need: 12 to 15 quarts of automatic transmission fluid, preferably Nissan Matic D A clear gallon jug, something like an empty milk jug Another large container to store used fluid for disposal 1. Disconnect the transmission cooler return line and secure it in a collection bucket such as a clear gallon milk jug. This will be the hose on the passenger side of the vehicle; disconnect the end leading towards the transmission. 2. Have a helper start the car while you watch the bucket - once it's half full (2 quarts), yell for the helper to stop the engine. 3. Add 2 quarts of ATF through the transmission dipstick. 4. Drain collection jug into larger jug (i.e. a Disposoil - these only hold 10 quarts though in my experience, so have something else to hold the last 5 quarts). 5. Repeat steps 2-4 until you're out of ATF. 6. Check fluid for proper level (see the next question and answer for details), and recycle the old ATF. Any place that takes used oil will likely recycle ATF. A Magnefine in-line transmission filter on the transmission cooler return line is also highly recommended. The Magnefine contains a very strong magnet to catch all ferrous wear material, and filtering media in the range of 35 microns to catch anything non-ferrous. Link to comment Share on other sites More sharing options...
The_Magicians_Eye Posted October 16, 2012 Author Share Posted October 16, 2012 so no change of the trans filter before doing this? I've done this in a Volvo that I owned but I changed the trans filter first. Link to comment Share on other sites More sharing options...
Towncivilian Posted October 16, 2012 Share Posted October 16, 2012 (edited) The in-pan strainer is a rock catcher, if it's catching anything your trans is almost certainly doomed. I would leave it be personally. Edited October 16, 2012 by Towncivilian Link to comment Share on other sites More sharing options...
Precise1 Posted October 16, 2012 Share Posted October 16, 2012 ^ I agree. However since last weekend now it has a burnt smell. No inline trans filter. Not good. Can you tell if you have flow? The return line with some temperature and pressure of the outline? Flushing is probably a good place to start. I don't know much about the autos either, which is why I put in a filter and temp gauge so I can hopefully mitigate any issues. B Link to comment Share on other sites More sharing options...
The_Magicians_Eye Posted October 16, 2012 Author Share Posted October 16, 2012 I'll give it a try and see what's up. I can see that working for the slipping but what about the trans acting like it don't know what gear is should be in? Link to comment Share on other sites More sharing options...
Precise1 Posted October 16, 2012 Share Posted October 16, 2012 It might be the same thing but there is always the tranny CPU diagnostics. The computer is behind the panneling by the rear passenger seat IIRC. Download the FSM in the Garage section, follow the instructions and look at the thread in the How To section. I'm sorry I can't really help more, I've not done it myself. This is my first auto tranny in over 20 years... B Link to comment Share on other sites More sharing options...
Harbinger Posted October 16, 2012 Share Posted October 16, 2012 No I haven't changed the fluid. I guess it makes since on why I should but they didn't tell be that I should so I figured it was good to go. I know they flushed the whole system a few times because they were worried about metal shaving in the lines from the damage that cause me to need to rebuild it in the first place. I don't know @!*% about transmissions much less these ones. Hell I don't even know what the trans computer looks like. I do have two external coolers because I don't use the stock cooler. The fluid looks as good as it did on day one. However since last weekend now it has a burnt smell. No inline trans filter. Do you remember what they used to flush the transmission with? If it wasn't straight ATF it might have been one of those harsher detergents washes. I've heard our trucks don't like the harsher chems. Auto's are black magic to me, so good luck? Link to comment Share on other sites More sharing options...
Towncivilian Posted October 16, 2012 Share Posted October 16, 2012 I've heard of supposed flush chemicals, but you have to remember that they wouldn't be in the transmission for very long assuming the shop opted to use, and even then, is there that much crap adhered to internal components to potentially cause issues? It's not like transmission fluid is exposed to the conditions engine oil sees - there's no blow-by, carbon build up, fuel dilution, etc. If a flush chemical was used, I highly doubt it did any harm. Also, be aware that no shop does a "power flush". I've never actually seen or heard of any shop having a machine that forces fluid through a transmission at a high pressure. Transmission fluid exchanges use the transmission's own pump and the machine used is simply a bladder for new and old fluids with adapters for the transmission cooler lines for proper connections. Even later versions of Nissan's own factory service manuals recommend a similar procedure to the one I posted above for a full transmission fluid exchange. I strongly think a full fluid exchange should be done first. If issues still persist, then perhaps do a pan drop & filter change to see if anything significant is wrong. If everything seems fine after just a full fluid exchange, install a Magnefine and do drain & fills every 15-30k and change the Magnefine every 30k from now on. Link to comment Share on other sites More sharing options...
Simon Posted October 16, 2012 Share Posted October 16, 2012 Bypass the factory cooler if you haven't already. Chances are that's why your original transmission failed. Buy the biggest cooler you can find, and hook the lines up to it. Plug the factory ones in the rad. Link to comment Share on other sites More sharing options...
Towncivilian Posted October 16, 2012 Share Posted October 16, 2012 He said he has two aux coolers and bypassed the stock cooler. 1 Link to comment Share on other sites More sharing options...
Simon Posted October 17, 2012 Share Posted October 17, 2012 He said he has two aux coolers and bypassed the stock cooler. Lol. Reading is key. I didn't see it in the original post, and I skimmed the responses. I fail. Link to comment Share on other sites More sharing options...
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