I only have third gear

[Drake57]

when in any forward gear position. Park, reverse, neutral all ok, but no 1st, 2nd, 4th or lock.

All forward gears worked no problem this morning, this afternoon, only third, regardless of shifter position (1,2,3,D).

Has anyone seen this before? It's a 1992. I have not had time to check fuses.

What a PITA! I hope to not have to swap xmission.

Can anyone say where A/T controller is located?

Thanks.

[94Q45Beast]

its behind a kick panel on the drivers side, left of the Hand-Brake pedal, atleast that's how it is in my 94

[Drake57]

Well ok, I was missing some of the fuses shown on the A/T schematic diagram, unfortunately, installing fuses did not affect missing gears. Nice thing is, after installing missing fuses, I now have the trip meter and self diagnostics display, for the first time since owning the car. I only seem to have half of the diagnostic display back light, I presume there are two miniature lamps for back light. Anyone?

In the A/T section of FSM there are some self diagnostics procedures, now that I have diagnostic display, I can at least try that. I have a feeling I know what the answer is though.

Happily, I think my parts car A/T is good, though I do not relish the idea of R&R'ing *two* transmissions. I'll have to go out and by some more jackstands!

Now how big of a deal is it to install a manual?

Happy monday everyone!

[Q451990]

You're correct that the diagnostic display is backlit by two bulbs. Let us know what the A/T diagnostic says... but I agree that you're probably in for some work. M/T swap has been done, but it's definitely not easier than the A/T swap.

[qship96]

I had that "only 3rd gear" operation thing happen once on my Q......turned out to just be the throttle position sensor was wearing out, Infiniti dealer correctly diagnosed and replaced that sensor rather inexpensively and never had another issue in well over 150,000 miles of driving afterwards.Maybe yours will be as simple of a fix too!

[3Q Jay]

yes, it may be a lot of things other than hard parts in the trans. 3rd is the 'fail-safe' gear because it is the only one truly needed (although i sure wouldn't want to lug the engine around all day thru town with only 3rd)....also try swapping the TCU if necessary. put in the 93 or later TCU and reward yourself with 1st gear start....

[Drake57]

It failed the AT CHECK in diagnostics mode, which points to inhibit switch, range switch, kickdown switch, idle switch, or TCU. Swapping the TCU from 1992 parts car fixed it - after TCU swap it still fails AT CHECK, but shifts normally now. Not too long ago I was having odd problems like torque converter lock at unwanted times, when crawling in traffic, or backing out of driveway.

Chart on page AT-30 of FSM is telling:
Gear position 1, shift solenoid A ON ; shift solenoid B ON
Gear position 2, shift solenoid A OFF; shift solenoid B ON
Gear position 3, shift solenoid A OFF; shift solenoid B OFF <<<<------- what happens if control system fails
Gear position 4, shift solenoid A ON ; shift solenoid B OFF

So as Jay correctly points out, 3rd is the limp home fail safe - makes sense, it will pull from stop, and run down the highway right smart(ly).

TCU board had a little brown goo around a couple of electrolytic capacitors, but who knows.

[Skibane]

TCU board had a little brown goo around a couple of electrolytic capacitors, but who knows.

If you've got a soldering iron, replacing those capacitors should be a simple, cheap job.

[Q451990]

Interesting! I've never heard of a TCU Failure before.

You said it's still failing the A/T diagnostic... what result are you getting?

[Drake57]

AT CHECK continues to display. I think this is the catch all, if for whatever reason diagnostic never receives inputs that signal the end of the test. It is listed at the end of the possible results interpretation.

I did not have time LN to run down why test never completed, was glad to have 4 speeds again.

[Drake57]

Can anyone say of transmission fluid cooling lines, which is the supply and which is the return?

Thanks.

[Q451990]

Keep in mind that the AT test has to be done while the transmission is warm. If not you'll get the AT Check result, even if there's not a problem.

The ATF coming from the transmission feeds the lower input(s) into the radiator, flows through the cooler(s) and returns through the upper line. I'm not sure if your 92 has the dual cooler tanks or just one on left side. I think the change-over in design was sometime during the 1992 model run.