I picked up a 86 with the A/T transmission. According to the previous owner the transmission was Rebuilt?Replaced 7500 miles ago. The receipt that he supplied just says "Rebuilt transmission/converter. The price was 2k for the transmission and converter. It might be a factory Mazda unit but I don't know as there is no tag or stamp anywhere on the transmission like it is supposed to be.


After I got the coolant leak fixed on the engine I was able to test drive it. Upon take off their was a lot of shudder/shaking going on and it slipped tremendously on take off. I inspected the drive shaft and there is no excessive play. After you get going and hit the throttle it would down shift and slip somewhat then gain speed. If you were going 40 MPH and floored it then it would down shift and accelerate normally with no slippage. The most amount of slippage is upon initial take off.

First rule of thumb is to check level of fluid. Was good. Reddish pink in color and no burnt smell. (found out that previous owner had issue and it would not move forward) then took back to shop almost 2 years later when this happened. They said that it did not register on the dip stick. They also said they did a inspection of the transmission and told him that it would need to be torn down to see what the failure was. So I am assuming they refilled the transmission and or inspected by at least taking the pan off.


When I pulled the pan I found a thrust washer (thick plastic/nylon) in 2 pieces. 1 piece was in the pan the other sucked up inside of the filter. The other odd things was that when I removed the screen to inspect underneath that 1 bolt just turned and was not secure. It just pulled out with my hand. Come to find out that it was not supposed to be there. (Picture of where bolt was attached).

I have not removed the valve body yet to see what that passage may be that the bolt was sitting in yet. I just have a hard time understanding how this happened? The kid said that he did drive it hard but not sure how he damaged it or if it was a defect from the beginning.

Note:

I never did get a answer from the kid stating why the fluid level was low when he took it in. I'll have to call him again on this.

Any insight as to what is going on would be appreciated.

Also with the amount of black residue (assuming clutch material and the fact that whatever metal pieces were cushioned by that thrust washer) do you think that the torque converter could be flushed out and reused since it is new?

 

Picture did not attach for some reason.

 

I've pulled apart a GM 4L60E, which is just the electronically controlled version of the old 700R4 and GM Turbo Hydramatic units with overdrive. I assisted my friend with his rebuild although he understood it a lot better than me. Automatic transmissions are far more complicated than engines. I remember my friend had slipping problems with his when one of the check ***** was installed incorrectly. There are a million other things that could be wrong.

According to the 1986 technical specs book, your '86 A/T is an L4N71B transmission. Wikipedia reveals that this tranny is sourced from Nissan/Jatco and is used in some form on a lot of cars: http://en.wikipedia.org/wiki/Jatco_4N71_transmission

Some diagrams are available here in this catalog from TranStar: http://www.transtar1.com/catDownload.asp?ID=764 . I am going to post the pics as well should anyone stumble across this thread some time in the future:





Unfortunately there is no break down of the valve body, which is probably what you need. I can't find a PDF of the actual service manual for this transmission online, so I suggest you order one. The GM 4L60E was pretty much impossible to work on without it, not unless you really do rebuild them for a living. There are so many tiny pieces in an automatic that you need diagrams to keep track of them. The GM manual also had an overall working explanation of what each solenoid and valve in did plus diagrams of how all the fluid flows through the valve body.

You're not going to be able to just guess, and I'd be surprised if an A/T guru shows up in this thread. Most technicians just remove and install transmissions that have already been remanufactured. The people who do crack open automatics (mostly specialists) usually work on GM transmissions more than anything else.

So go buy a service manual. The ones from TranStar are great.

 

Thank you for taking the time to post what you did. However I am aware of these things and have examined the FSM. I know exactly what type of transmission it is and that it is used in other applications.

What I am after as stated if a "Guru, or "Tech" that actually has working knowledge can give some insight as to what that passage is under that opening and by being blocked off by a bolt what if any damage would that cause and what may have caused a transmission with 7500 miles on it to break a thrust washer? I know that they cannot know 100% as far as why it failed but can give some insight as to what might have gone wrong. :-)

 

I'd be very surprised if you will get direct input from someone who has rebuilt a L4N71B. A TH350 maybe, but not a Nissan transmission. From the couple of specialty shops I've dealt with I'd say it's usually GM and Chrysler truck automatic transmissions that are built in-house. The GM turbo hydramatic family is an especially well known tranny and it gets swapped into a lot of different projects, especially offroading and drag cars.

You need to get the service manual for the L4N71B. It should hopefully give you enough diagrams that you can answer your own question regarding the consequences of modifying or blocking off something in the valve body. As for why it failed, it may have been put together improperly (some clearance is wrong or something) or it used/reused components that were defective or simply out of spec. That could have ultimately resulted in you blowing out that thrust washer.

Do you even know if this transmission shop did the actual rebuild? How do you know it wasn't just a reman they installed after making the initial diagnosis? Did the previous owner give you a receipt for the work?

 

Although it is much appreciated that you are replying to this thread and trying to help but please stop!

This is not my first Rodeo! I posted that I have a receipt that states "Rebuilt Transmission/ Converter which probably means that the shop bought it from the "Mazda" dealer or elsewhere but did not rebuild it themselves. Even Mazda dealers do not rebuild their own A/T , they just put in a factory rebuild.

I don't need the service manual as I have downloaded the FSM that has detailed information on this transmission!

I just want and for the last time, information from someone that has either rebuilt, dealt with this situation or works at a transmission shop that is a member of this club, end of story!

Again thank you for your help.

 

if it was rebuild, and they put the clutch packs assembly wrong ,,it would run but it will slip and not last you very long,, theres a certain way that you can assemble the clutch packs on all automatic tranny