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Automatic Transmission replacement recommended by dealer

wilsonp

wilsonp

Experienced Member
Joined
3 October 2001
Messages
461
Location
Danville, VA, USA
After fixing a few issues and now this, I'm starting to feel unfortunate about the Acura/Honda reliability story.

Can I get some second opinions before I get another transmission?

1991 NSX Automatic, 80k miles. No mods to engine.

Symptoms:

1. Start car, drives fine for a few minutes.
2. Get up to speed (75 MPH) and after 3-9 miles, revs jump until gas released.
3. Put in neutral, turn off engine for 5 seconds, turn back on.
4. Resume driving at 75 MPH.

After 2, shifting gears manually does nothing. Coasting down below 25 or so in neutral, then trying to put in drive sometimes works.

Dealer replaced transmission fluid a few weeks ago. Flushed again for this problem, nothing observed in fluid.
Dealer replaced speed sensor due to computer code. Didn't fix. Now wants to replace transmission.

Questions:

1. If this is a mechanical issue, why does turning off engine fix for 3 - 9 miles?

2. Is there some definitive way to confirm problem is inside transmission before getting another one?

3. How unusual is this at 80k?
 
My question is have you noticed any problems with the car before this? Also, how often has the transmission fluid been changed before this problem occurred?

I have a 1991 NSX with over 134,000 miles and an automatic transmission and it has not given me any problems at all.
 
In general, dealers are EXTREMELY POOR at diagnosis, if they do it at all.

They are very good at removing, replacing parts and billing until the problem is fixed. This is what they are doing now and it is an accepted business practice.

It DOES sound like you have a control issue, rather than a mechanical issue. Probably a stuck actuator or maybe the torque converter lock-out is not happy.

You NEED to call around and find a dealership that has the diagnosis harness for the automatic transmission. This harness allows the tech to isolate issues down to individual sensors. Honda should know which dealers are certified and should have a full compliment of tools for specific models.

Now, if you can find an independent (or chain) shop that has a harness for a Legend that might work too. Some shops have a co-op where they will share such tools.

Without this harness, you might as well replace the transmission. As the time and effort trying to diagnose (what may be a very simple and inexpensive fix IF you knew the specific issue) will almost always exceed the cost of rebuilding the entire transmission.

Now that I think about it: I would monitor the lockout. Run a couple of wires to the lockout actuator with a very small 12v light/LED and run them into your car.
 
Got a 92 AT here with 50K miles. So far so good, but I always try to get a second opinion from a couple shops that other NSX folks go to before making any decisions. Hopefully your problems turn out to be something minor.
 
If you can't find anyone around you, BarnMan rebuilt a manual transmission for me in Nashville. It may be worth your time to take a trip if you can't get someone good locally.
 
114K miles with auto tansmission and no problem. ECU problem maybe?
 
our nsx is a 91 auto that has a ctsc, and it started out like IsR's and 3rd gear wouldnt work. and now within the last week its doing what wilsonp's is doing. i honestly cant figure out what is going on, it seems very much electrical, or some component of the tranny but not the tranny itself. i really would like some answers
 
I had this type of problem with my 1988 Prelude (AT).

Check the lock-up & gear select solenoids for internal contaminants (iron/metal).
As the solenoids are electro-magnets, over time they could get clogged with small metal particals from normal wear of the gears.

You can do this by removing the lock-up solenoids, see the online manual on page 14-5 for this. Stick a iron rod like a paper clip carefully in the orifice to see if any particles stick to it as you retract the paperclip. It helps if you magnetize the paperclip first. In my case a lot came out and I pryed open the lock-up and gearshift solenoids and they were full of metal goo thus inhibiting good operation. Cleaning them and replacing the ATF twice gave some improvement however after a while they clogged up again.

So something else was still fouling up the solenoids and I ended up opening my transmission finding a possible culprit: a 2 dollar spring had broke in two and had to wait 2 weeks for the part to arrive from Japan. The rest of the transmission showed no signs of wear, except for the broken spring. So the torque converter had to be source of the metal particles. I opened up the converter which showed burrs/scars on the inner converter housing and rotors. Reason for scarring of the converter? Still unknown.

Opening up the solenoids is a no-no for Acura/Honda mechanics. You could pry them open yourself if you are handy enough or you could replace them. However replacing them will cost this experiment approx. 2x $160 (lock-up & shift solenoids). If I had the same problem with the NSX, the cost for solenoids, converter, ATF & AT gasket set would be approx. 1850 USD. while doing all the work yourself.

In short: Test your solenoids. Clean/replace if needed. If problem still persists remove/open up the transmission.

Back to your questions:
1)
I guess shutting of the engine / internal flow of ATF in the transmission shifts some of the metal goo so normal operation is resumed for some time.

2)
I hooked up some leds with resistors (or 12v lamps) to the solenoids and placed them on the dash and observed if the solenoids were actuated correctly by the computer. In my case the electronics were OK so it had to be mechanical.

3)
Ehh, nobody/nothing is perfect. It happened to me at 120k km's / 75k miles.
After repair it held up until sold at 240k km's / 150k miles.
My current Prelude AT is now at 300k km's / 190k miles without any mechanical failure.
Your NSX loves you so much it just wants you to get more intimate!
Time to dig down deeper in you relationship/transmission.:biggrin:

Best of luck, Roger.
 
My 94 auto did that and I did replace the transmission- now I have 130k miles-

But I suspected the problem occured after I had the trans fluid changed per owners manual.

Note- wives hate this kind of expense.
 
IsR said:
The last owner used some 'aftermarket' oil which I think could be the cause. Other then that there was no other variables
Click to expand...


Sorry, I read the other thread and I got confused about who was who. It can be wrong to use a different oil but I agree it would cause total failure if anything.
 

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