tranny doesn't shift outta 1st

[kpring]

New to the Nissan part of this forum. Hope you can help. Driving my father-inlaws 1993 Sentra with 100,000 miles on it this AM in 30 degree weather, and about a mile into my trek home I stopped for a traffic light and when I resumed, the transmission wouldn't shift out of 1st gear. Didn't matter whether I manually shifted it or not, it stayed in 1st all the home (8 miles or so). Doubt if the fluid has ever been changed. Hopefully that won't be a PRIME reason for this failure. I kind of need to fix this myself. Any good places to start?

[slideways...]

drain the fluid. look for metal in the fluid. if metal content is on the copious side of bad, look around junkyards for a new tranny. next, check the clutch master and clutch slave cylinders. replace if necessary. if your pedal is adjustable, adjust it tighter to see if it helps. if it doesnt, adjust it back and move on to the next thing. after that, if it still doesnt wanna shift, drop the transmission and examine the clutch/fork/fork pivot/ect. in the bellhousing. if thats all free moving and in good shape, get a new transmission. you could try and disassemble the transmission and rebuild it, but its not a walk in the park. myself, id rather rebuild a motor than a transmission.

[kpring]

Opps, I should have said it was an automatic transmission. Appreciate your quick reply though. I checked previous threads and saw one that said to disconnect the battery to let the computer reset and give it a shot. I would like that kind of fix if it works.

[nismo_pilot]

has this problem reoccured or just when it was cold? did you run it to redline to see if it shifted all the way at the top? give me a little more info and maybe i can help you

[slideways...]

could possibly be either low on fluid, about to die, or maybe a transmission speed sensor? dont know for sure how nissan does it but some cars wont shift if the speed sensor is bad.

[nismo_pilot]

any of those could be it, autos shift on a pressure differential between sensors that detect throttle position and output shaft speed, when the output shaft spins fast enough to overcome the throttle vale pressure, an upshift occurs....... he could have clogged lines, low fluid, if its got electric controls it could be a faulty vehicle sped sensor, bad govenor (creates pressure based on output shaft speed), vaccum to the throttle valve could be too low making the tranny believe the vehicle is under WOT or just making throttle valve pressure so high no amount of govenor pressure could overcome it, or the cold weather couldve frozen either moisture, or his tranny fluid in the case or between gears, making shifting impossible...... some trannies use a limp mode type of thing but it usually defaults to second gear so idk about that, let us know some more info and maybe we can help you dude

[kpring]

I had'nt gotten any replies to my query in a few days so boldly went where I have not ever gone before. I just drained the oil and it didn't look or smell bad, checked it cold and it was up to level (would the difference between hot and cold, when the cold level shows full, be enough to have this no shift out of first problem happen?). Tried taking off the filter but out of the 10 or 12 bolts holding it on, there is one that just doesn't want to come off. It spins, spins tightly even but won't unthread. I have a post in another automotive/tranny forum to see if I can get any help on that (almost like there is a nut on it). I gave it a once over as far as looking for cracked vacumn lines, this is the first time this problem happened. I had to drive it home in first for about 8 miles, so I know the RPM's maxed out on a few occasions during that drive. I also have to think the tranny was warmed up by the time I got home. I'd say the outside temp when I drove it home could've been mid twentys, cold, but not sub zero. I should say my father inlaw has one leg and is wheelchair bound and rarely uses the car, maybe a couple short trips a month. He just went into the hospital for a few days and with recuperation, we decided to take the car and start using it, so we probably put 7 or 8 months worth of "his" miles on in the past two weeks. I guess I should get a manual for it, and start in on some the suggestions you guys have offered. In the mean time I'll keep yoiu informed of my progress, and I'll appreciate your feedback.

[nismo_pilot]

fluid level should be in between add and full, i would say check it warm and adjust it until it is at or under full when warm, that may be creating too much pressure not allowing an upshift, it would be easy to try so let us know what you find afterwards

[kpring]

Will do, once I get that dang filter off! Its snowing right now, have to wait until tomorrow.

[nismo_pilot]

goodluck!

[kpring]

No luck with this nut. Here is a picture, it is the only one with out the ridge around the head of the nut, and it is the one right in the center of the photo. It is different for a reason. It just spins and spins. Doesn't jump a thread after a complete revolution,but spins tough enough that you can't spin it with your fingers. I hate to go this far and not take off the filter before putting it back together.

[nismo_pilot]

use needle-nose and pull when you twist?

[kpring]

Tried vice grips and pulling down as I turn - still no luck. Nothing ever goes smooth with these projects, you'd think pretty simple, take out the bolts drop the filter and check for crap. Down to one friggin bolt and three days later and still no where!

[slideways...]

that sucks dude. that screw is stripped. i dont know why but my old sentra had that happen before i bought it. when i tried to change the filter, someone had already replaced that screw and it seems like the threads in the transmission were pretty fucked up.


oh and nismo pilot, this may be more your area. i have some experience diagnosing wierd transmission stuff like this at work, but as far as how transmissions work(internally and stuff), i know next to nothing, especially automatics.

[nismo_pilot]

only other thing i can think of is trying to get a flathead screwdriver under the head of the bolt and pry down as you try to unscrew the bolt with a socket.....