I've been having troubles with my automatic transmission for sometime now mainly it's lost it's smoothness and has been slipping first thing in the morning. I've practically worked on every other component of a car but never ventured into or near a transmission so I don't know where to start. Basically, I shifted into reverse as usual the other day and recently whenever I've shifted into reverse its been a rather rough engagement but this time there was a more decent thud and now reverse is just another neutral gear.

All my other gears work as expected, except it's now more rough going into drive sort of like how reverse was engaging for a while before it finally failed, which is concerning.

The situation:

  1. -Have only owned the car for a few months
  2. -Haven't changed the trans fluid or filter or any of that, fluid looks a little light brown but is at the correct level
  3. -Right hand outer CV seems to be knocking too

Haven't had any time or place to raise her up and take a look at it all properly but I do notice some fluid on the left hand CV that I can see from above. I've also noticed that it seems to smoke almost twice as much in reverse as it does in drive (usually only when I first start it up on these cold mornings).

I read somewhere that an item called a "vacuum modulator" can fail and suck trans fluid into the inlet manifold and cause the car to smoke white which is what it does in reverse, but as I say transmissions are not anything I've looked at before so I can't confirm or deny that. I'm planning to have a proper look on Sunday, if any photos would help please let me know and I'll take some.

I also have a rebuild manual for the transmission and all other related components I grabbed so that should hopefully help too with any advice.

Cheers guys!

  1. Year: 1997
  2. Make: NISSAN
  3. Model: PULSAR
  4. Colour: White
  5. Submodel: CJ II
  6. Body Style: Saloon
  7. Engine No: GA15-458374 (GA15DE)
  8. Chassis: FN15-458374
  9. Transmission: RL4F03A
  • Is it safe to share your VIN number online? I wouldn't add it to this question if I were you.
    – Dan
    Jul 16, 2015 at 10:26
  • Anyone can read the VIN on your dash while walking by your car. I don't think there is any harm in posting it online. However, I wouldn't suggest it.
    – rpmerf
    Jul 16, 2015 at 15:01
  • Cheers guys I took it off, I didn't really consider it an issue but you make a good point!
    – Krystian
    Jul 16, 2015 at 20:17
  • Having said that @Dan here in NZ if you've got my number plate you can type that into a free site called carjam which gives you all the details I copy and pasted above and it used to give names too but they removed that only a couple of years ago!
    – Krystian
    Jul 17, 2015 at 4:22
  • I have exaclty the same problem with my car so what this the problem? Do you fix the problem? Thanks u Jul 15, 2017 at 7:19

3 Answers 3


While I would love to tell you to just go for it!, in the case of an automatic transmission I really cannot. It's not something the average Joe can tackle with any kind of confidence and complete successfully. Even with a good rebuild manual, it's not something you want to do uninitiated.

That said, it sounds as though (besides the problem with the vacuum modulator you may be having) either your reverse band is shot, your solenoid actuator for the reverse band is shot, or both. I really think you have a lot more going on here than just that though. You are stating the transmission is running weird, so I'm thinking it's time for a total rebuild. You'll want to do this sooner, rather than later, as the more soft part debris which builds up in your tranny, the more damage it causes to your hard parts. Your transmission may be at the point of no return, where it's going to cost more in parts to fix it than it would to find a good used one to replace the old one. Although, if you have the means of removing the transmission yourself, I'd bet you can find a shop which will rebuild it for you. The job of removal/replacement can cost some $$ (or maybe ₤₤ in your case). Can definitely save you some money.

  • Yea I think this is why I haven't already made any attempts because an automatic transmission just seems like a different animal, and from the control circuit diagrams and hydraulics it literally looks like those ball maze puzzles you see sitting on coffee tables. Having said this, I don't have enough money right now to throw this transmission into a shop, and I'm finishing my final year in a Bachelor of Engineering, so it could be an interesting exercise?
    – Krystian
    Jul 16, 2015 at 0:38
  • @Krystian - Good on you if you can. Just remember: cleanliness, cleanliness, cleanliness. Especially where auto trannies are concerned. Keep track of everything. Be prepared as there may be more wrong with it than something simple. Jul 16, 2015 at 0:55

If you're confident at general mechanics, and fancy having a go, why not get hold of a second-hand transmission, swap that into the car, then have a go at rebuilding the original? That way, if you do screw it up, or it turns out to be unfixable, you're not stuck as you've got the replacement in the car...

  • Not a bad idea. If the OP can get the original rebuilt and back in the car, they can always resell the second transmission again and recoup the funds. This would give minimal downtime with the vehicle. Jul 16, 2015 at 10:51
  • Swapping in a junkyard tranny is the most cost effective way to get the car back on the road again. Get one from a car totaled on the rear if possible. A smashed car was at least drivable before the accident and isn't there for a bad transmission. If you like driving a stick, now would be time to look into doing a swap.
    – rpmerf
    Jul 16, 2015 at 15:10

My car is KIA Grand Sportage Turbo Diesel,base to my experienced with this car I found out that it is not the transmission affected.I notice theres no noise coming out from transmission everytime i transfer the gear from reverse to drive.I decided to take out the TPS(Throttle Position Sensor) in the throttle body and then i fix it again but loosen the bolt and start the car and i slowly adjust the TPS in normal idle then tighten the bolt.While the car is still starting i tried to put the gear in reverse and it work,so I'm glad i can drive my car again.Only theres still a problem of TPS coz sometimes the condition is not stable,i know the TPS is faulty so immediately i order on line for replacement.

  • Welcome to Motor Vehicle Maintenance & Repair! While this may have sort of worked for you, I'm not seeing as how it in anyway is going to help the OP? Your "fix" is quite unorthodox in many ways. Really, you shouldn't mess with the TPS to adjust the idle and will cause all sorts of other issues in the process. Nov 8, 2017 at 14:33

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