My 94 has intermittent shift problems. Seems she doesn't always want to upshift. Have to turn her off, restart, wait for the idle to drop to about 650 (ingear), and then she goes OK for a while. Is this a common problem with these cars? Other than that, she's my pride and joy. Had my mechanic look at it and he suggested some sensors/switches replacements. Hasn't helped yet. Help, please...

Common problem with S13 autotrans. Seems to be worse in convertibles.

I did a pan drop, filter change and new fluid (with a bottle of LucasOil trans treatment) and it seemed to make a big difference.

Make sure to clean out the pan and remove the magnet and clean it well.

"seemed to make a difference" to what degree? Sometimes she runs like a dream, and sometimes more of a nightmare. No rhyme or reason, either. Has your transmission problem been fixed, or is it now more or less acceptable? Thanks for answering and giving me some help and options.

Nope, I spoke too soon.

It accomplished nothing.

Mine slips approx 10 minutes into driving it (from a cold start), and once it quits slipping, it drives fine (until it gets cold again, then starts all over again).

Pulling the autotrans for a manual swap in 2 weeks, auto rebuild too expensive.

Are you going to do the swap yourself, or are you going to hire someone? Let me know how that went.

Having the local guys over to help.

We have some great "tech days"!

Hey AZ..

I know it's a lot of work.. but it would be very cool if you did a pictoral how-to guide for everyone else to follow in the future. I have seen other's do bits and pieces with pics, but never a real good step by step tranny swap guide.

just an idea.

Good luck with the swap. Nice to see another SHIFT---Convertible around.

oldbald_sarge wrote:My 94 has intermittent shift problems. Seems she doesn't always want to upshift. Have to turn her off, restart, wait for the idle to drop to about 650 (ingear), and then she goes OK for a while. Is this a common problem with these cars? Other than that, she's my pride and joy. Had my mechanic look at it and he suggested some sensors/switches replacements. Hasn't helped yet. Help, please...

I have a HB and it doess the exact same thing. Myself and others have been trying to figure it out on the tech. fourms but we have come up with little. We think it is electrical most likely a short or bad sensor. I don't think anyone has yet to figure it out, but the throtle positioning sensor and speed sensor might be part of the problem. Good luck!

Same problem and symptoms here with 92 240 Conv. Only happens in a brief period about 7 to 10 minutes after a cold start or right away if the car has been shut down for about 20 minutes. Turning the key on and off clears it. I was thinking it was electrical but also have had the car drop back into and stay in first if I hit a sharp bump when just starting during that warming up period. But, if I start out real slowly it may not stick.

Throttle position switch adjusted with minor improvement. Flush improved all other shifting characteristics but hasn't cured the base problem. I'll report any significant progress..........if it occurs.

Identical to my symptoms.

Down to the exact timing....

Had the same problem. I knocked a sensor loose when tightning my belts. Searched and searched and couldn't find it. I took it to an auto electric place and they fixed it for $35. I just put the 5 speed in a few months ago because the auto was nothing but problems. good luck.

I've got the same problem with my '92 conv with AT (started at about 145,000). I notice the problem after 5 - 10 minutes of driving, and it is always worse in warmer and more humid weather. Usually the problem occurs after waiting at a stop light and the transmission will not shift up. Occasionally the transmission will downshift while driving for no apparent reason and get stuck after that. The only ways I have found to remedy the problem while driving is to 1) stomp on the gas, 2) drive near red-line RPMs until the car shifts, or 3) if I can get the car up to 40 on a downslope the transmission will usually then shift up on its own. Any suggestions on a cheap fix would be most welcome.

Yep - Same as mine.

I swapped to a 5-speed, thniking I had a bad trans.

smc2017,When you say that you had a sensor loose and you had an auto electric place fix it for you, did this correct your AT shift problem or did you already have the 5 speed put in it when you had them fix your loose sensor? If this did fix your AT shift problem, which sensor was the culprit?????

I have the exact same problem to the "T" as everyone else here in this forum with this auto tranny! I'll be waiting to hear back from you. Thanks!!!!!

240rocker

I said sensor, but I think it was actually a wire into the wire harness. It did fix the shifting problem, but shortly after I ended up with a hard shift problem. Bad solenoids in the tranny were causing that. Fixed that and more crap happened. If you can put in a 5 speed you will be more happy. I did it 5 months ago, and I haven't had to fix anything since.

I'm far from ready to declare success, but addition of a bottle of Lubegard has reduced the "hangup in first gear" problem from every trip to once in the last ten days.

OK guys...I am determined to find out why this Auto tranny is behaving in this manner. There are just too many people on here that are having the same problems as we are. Here is what we know so far. The car seems to not want to shift into 2nd gear from first, sometime during the first 20 minutes of driving. It seems to happen more frequently when it's warmer outside and when there seems to be alot of humidity! It seems like the only way to temporarily correct this is to shut the car completely off. However, all we are doing when we do this is resetting the ECU back to default condition. That is why we are able to continue driving without the problem until the next time we drive after letting the car rest for about 20 minutes. I have also put in some tranny additive that is supposed to cool the tranny fluid temperature down about 10°. This worked for about two weeks, then it started happening again. This is definitely a heat/temperature problem based on these symtoms.

This weekend, while driving my car, I'm going to hopefully get the car to exhibit this shift occurence and when it does, I am going to try and get the codes out of my ECU to see where it might be failing.

I have had this problem for about two and a half years now and I have taken it to two different Nissan dealers and of course it wouldn't act up on them so I never got anywhere with them. One dealer did a $160 tranny flush and the other dealer charged me $35 to drive my car for an hour. I had a transmission shop look at it also and it never acted up for him either, but he suggested that maybe the TPS was bad so I replaced that too.

Does anyone here who knows anything about the TCU think that maybe this could be the culprit? I work with electronics everyday and I know how picky some circuits can be when they go thru temperature extremes. What exactly does the TCU do? Does it actually tell the tranny when to shift gears? I found a place in Florida that repairs and sells these for around $250. Someone else also mentioned that maybe the 1st to 2nd solenoid in the tranny could be flaky. I talked to another transmission shop the other day and he told me that if it was the solenoid it wouldn't be bad at all to replace. All you have to do is drop the pan and check the solenoid and replace it if it's bad.

OK guys these are the things that I'm looking at and as I find out more info I'll let you know.

Oh...and I could very easily put a 5-speed in, but I really want to know why this is happening to our Auto tranny's. I am determined to find out.

I'll keep ya posted and anymore info you can offer would be great too!

Thanks!!!240ROCKER

Have any of you had to replace your radiator before you started having the shift problem? If so, did you buy an OEM or aftermarket radiator?

I replaced my radiator, but not because of the shift problem. Just bought one at NAPA, was a direct replacement. Make sure you bleed the hell out of it, or you will have overheating up the ***.

Nah...I'm not saying I replaced my radiator due the shift problem. I'm saying that when I had a problem a couple of years ago with my car overheating that I replaced the radiator with an aftermarket one and ever since then I have had this intermittent shift problem!The overheating problem was fixed, but the shift problem was created.!

240ROCKER

Has anyone who has had this shift problem ever red-lined it to see if it will shift into second?

Another question I have is if I take off manually in first gear will the car automatically shift into second as it approaches red-line even though I'm in first?

No.

Mine would rev to the rev limiter (I feared damaging the motor).

Manually leaving the car in first will hold it there.

I have redlined mine several times seeing if I could get the tranny to shift, but it didn't work. I don't recommend it.

I have been taking mine to shops in my area, but no one knows what is the matter with it.

Recently I had an episode where my car didn't shift. I shut it off and restarted it, but this didn't work. I tried again and got it to shift. Ever since that bad episode it shifts kinda hard and makes a whining noise at low speeds. I am about ready to have the transmission rebuilt. I guess 2 years of this problem has taken it's toll on the car. I wish I could figure it out!

Well guys I found out something interesting about having your automatic transmission rebuilt. Apparently, when you opt to have your automatic transmission rebuilt, this does not include rebuilding the "valve body" which is the brain of the transmission. Several people have posted on here and on other places on the internet who decided to rebuild their transmissions only to find out that they still had the shift problem. What a bummer to know that you spent all that money for a rebuild and it didn't actually fix the problem.

The valve body has all sorts of control valves and springs and is a very expensive part to replace, which is why most tranny shops don't rebuild or replace these.

I have learned that more than likely I have a stuck control valve in the valve body and the reason that I normally don't have a problem in colder weather (50° or lower) is because there is more pressure being built up in the valve body to compensate for the colder temps. and when it's warmer weather, the pressure isn't as high and therefore one of the control valves that pertains to the 1st to 2nd shift is getting stuck. I was told that an additive called "Transmedic" might unstick this valve. It will take about two to three weeks to really get into the system, but that it might keep that control valve from sticking.

What are your thoughts on this?

240ROCKER
Modified by 240ROCKER at 1:03 PM 3/1/2005

I haven't heard that before, but it make sense. Thank you for the help.

The thing is, my car repeatively has issues shifting into 4th also.

Is there one valve body, or are there multiple ones that control different trans functions?

There is only one valve body, but there are lots of tiny valves and springs that control the following: Torque Converter relief valve, Pressure regulator valve, Pressure modifier valve, 4-2 Sequence valve, 4-2 relay valve, Overrun clutch control valve, Overrun clutch reducing valve, Shuttle Shift valve, Lock-up control valve, Pilot valve, Accumulator control valve and these are just the valves in the top body of the valve body.

The lower body of the valve body has these valves in it: Servo charger valve, 3-2 timing valve, 1st reducing valve, Manual valve, Modifier accumulator valve. So as you can see there are a bunch of valves in this very intricate part and this is more than likely the cause of our shift problems. One of these valves is getting stuck and not operating properly.

I'm going to try this Transmedic additive made by GUNK and I'm going to see if this fixes my problem. I will give it a few weeks and see what happens.

240ROCKER

Wow, the valve body does have a lot of parts. I think I will try the additive too.

Thanks for the info!

I tried Transmedic about 18 months ago and I had the same experience as the person who posted about using Lubeguard - it might have helped for a few days but soon the transmission was up to its old tricks again. I've still got half the bottle on the shelf in the garage, so maybe I didn't get enough into the system, but I didn't have much luck with it as a permanent cure.

I'm curious to know if 240Rocker's ECU codes have yielded any clues as to what the problem(s) might be...

Well...yesterday the temperature outside was 45° and I had the shift problem while driving. As I have stated earlier that this problem doesn't usually happen in colder weather, but it did yesterday. Anyway, I quickly pulled over to a side street and turned my car off and looked at the ECU code and there wasn't any failure code whatsoever. I had a '55' which is a code for everything is fine!

It is my understanding that you need to pour the entire bottle of Transmedic in your tranny and wait a good two to three weeks to get in your system.

Has anyone used the new Dexron III in their auto tranny's yet? I have also read on other forums that this might possibly fix tranny problems as well. There are so many possible solutions out there. I just wish we could find one that everyone is in agreement with!!!!

I'm still determined to get to the bottom of this!

240ROCKER
Modified by 240ROCKER at 1:10 PM 3/2/2005

I tried that Dexron III Mercon for my last fluid change. I also used Seafoam Trans Tune just before I changed the fluid and filter. I noticed an incredible difference in shifting for about 20 minutes after, but then it started to screw up again.

The only thing I might have done wrong was not leaving the Seafoam in the transmission long enough.