94 won't shift into overdrive

[dnudelman]

This is the first winter that I've owned the car. Tempuratures dropped to the low 30's. I always warm the car up for 5-10 minutes and this week I noticed on freeway speeds, the transmission stays in 3rd and won't upshift.

History- 112K Miles
I purchased in august 2013
Added trans oil cooler
Synthetic tranmission fluid (Valvoline)

I am wondering if I have a bad thermostat. Do get warm air from heater.

Did the AT self test and AT is OK no faults

What am I missing?
thanks
David

[rabsusa]

check speed sensors,,,

[dnudelman]

check speed sensors,,,

do you mean the turbine speed sensor? No codes on the TCM, how do you check it before replacing?
Are there any good tricks to make the job easier?

thanks

[elwesso]

If you're not getting any codes or a "transmission malfunction" light on the dash, then it's probably something inside the trans...

[dnudelman]

If you're not getting any codes or a "transmission malfunction" light on the dash, then it's probably something inside the trans...

No to both of those.

[BCC93QT]

Not shifting into 4th is some sort of TCU fail safe I recall. This same issue seems to re-occur here. I remember seeing this type of issue multiple times and it is a semi-simple fix. I just cannot recall what it was. I bet it can be found with a few hours of researching previous like symptoms on this site

[dnudelman]

Thanks,
I've done a pretty good seach on this site and it appears that the Fail Safe reset is either
a. Look for a blown fuse, both fuse boxes and fusible links
b. Turn key off for 3 seconds.

I have tried both, no success. In fact I pulled out every fuse and examined it.

Current status
Transmission will not shift into 4th gear. 60mph, 4000 rpm/ In Drive, take foot off gas, no engine braking
Move selector to 3 and I have engine braking
from a full stop, you can manually shift into 1st and 2nd.
AT check self diagnosis - No codes.

I have a brand new ECU Talk cable and ECUTalk, but sadly doesn't appear to do transmission diagnostics
I am pulling ECU codes 34 Knock Sensor and 51 Injectors. Inject5 is bad with 2K ohms, one of the knock sensors has very little resistance.

I have a plan to do injectors, knock sensors, plugs, gaskets, hoses, pcv etc but want to determine what is the transmission problem first.

Any more suggestions appreciated.

[dnudelman]

Update
$150 diagnostic at the dealer today. The Tech says 3rd gear is gone, transmission is bad.

I'm thinking JDM?

[BCC93QT]

Pretty sure the JDM G50 transmission is identical to the USDM. Besides the normal yearly changes and other than cost of course. I could be wrong. 5 speed would be the most beneficial to the driver but not the most cost effective. Honestly. Find another G50 Q that has a good working transmission and swap what you can. Installing a transmission on a 20 year old car is not the best route. It will be a hole you cannot stop digging. As I see it the only reasonable way to keep a Q (or any 20 year old 50k car) is to buy a parts car here and there. I would not suggest spending that much money on the transmission even if if you love the car.

[OwnerCS]

I see a post on here for a guy in Toronto parting out his 94 with a working transmission. Buyer and Seller may have already worked a deal.

[dnudelman]

UPDATE!

Amazing as it sounds, I found a local JDM engine shop that had about 1/2 dozen transmissions on the shelf.
The quote for the transmission was $449 and $375 for installation, $90 for oil and filter.

At the start of installation, unbolted a corner of the pan and I was able to see it was clean, no crud in the pan.

The following day, the car was ready. Transmission seems to be working normally.

Warranty:
Parts 90 days
Labor 60 days.

Now on to solve the injector, valve covers and knock sensors

[OwnerCS]

Good news for sure.

[BCC93QT]

Congrats. May I ask why you think the JDM transmission is superior to the USDM?

[dnudelman]

I believe they are identical.

1. JDM's are claimed to be low mileage, 50k or so
2. Where are you going to find a low mileage domestic? These cars are 20 years old in the USA but they were still making the President in Japan up until the mid 2000's
3. The supplier had quite a few on hand.
4. The supplier did the install and offered a parts and labor warranty (short).
5. The Nissan reman from InfinitipartsUSA.com priced out at over $2300 delivered plus installation.
6. Its gamble, but at 1/3 the installed cost of a Nissan or local rebuilder. Since I was able to inspect the transmission before install, that helped reduce the anxiety. Local helped. The ebay sellers were back east and I am in Seattle. As you pointed out in a post above, does it make sense to drop $3k into the transmission? I still have injectors and valve cover gasket to. I just did the steering rack, which was $275 plus another $300 labor. I am trying to decide whether do to the injectors myself. The how-to-guides on the forum look pretty good and I'm a decent shade tree wrencher.
7. I researched the seller on BBB and the internet and they seem to have a good reputation. They literally had hundreds of engines and transmissions in their warehouse.
8. I gave the mechanic a nice tip before the job and he was very appreciative.

All that said, I've been driving it for 3 days now and all seems normal.