The Dreaded Slow 2-3 Upshift When Cold - 90 Q45t

[JohnPa]

If you are looking at this thread, you know the problem and you too are worried about slowly burning up your transmission. I've been trying to find a difinitive answer in the older posts, but no luck, except for what 3Q Jay tried with limited success(many thanks for your response).

Long question shortened into two:

1) Has anyone actually tried the shifting resistor marketed for the Subaru SVX? If so, how did it work?

2) Will replacing the shift body and related shift solenoids, such as shown at, "re4r03a vs. re4r01a valve body" solve the problem?

I would rather put money into preventive maintenance now than replace the entire transmission later. Thanks for any help...........John

[GseaQ]

Hi John,

What's the mileage on your transmission? What's the maintenance history for your transmission - particularly fluid flushes and transmission cooler configuration?

Glenn

[JohnPa]

Hi John,

What's the mileage on your transmission? What's the maintenance history for your transmission - particularly fluid flushes and transmission cooler configuration?

Glenn

The transmission was replaced by the original owner at about 33,000 miles under warranty. I bought the car at 91,000 miles and flushed the system, installed synthetic fluid, and custom fit a newradiator from the later Q's that has the extra cooling coil in the ends. It also has the extra external filter and a small copoling coil under the froint of the transmission. The car now has about 107,000 miles on it.

It has started slippin on the upshift when cold during the last year. If the new shift body and solenoids will cure the problem, I'll go ahead and put a higher stall converter in at the same time. If the shift body won't fix it, I'll just wait until it goes bad and replace it with a rebuild.

Thanks for your help............John

[3Q Jay]

John, i don't think just replacing the valve body is going to do it.

as i mentioned in another post, you can compensate by forcing more pressure to the two functions of the 2-3 shift. this requires drilling out existing holes in the separator plate to a larger size. somewhat of a crap shoot though and there's no going back short of buying another plate.....

i compensated the factory 14ish ohm droppping resistor and am running about 35 ohm 40 watts. of course, this affects all of the shifts, not just 2-3.

best would be to buy a programmable TCU, whereby you could 'tune' each shift and map firmness to throttle position, etc.

i can't afford the $700 experiment right now.......

[GseaQ]

Hi John,

You seem to have a good knowledge of what is required regarding maintenance.

Let me tell you the history of our '92's transmission. For the first 7 years and 95,000 kms (~58,000 miles) the car was maintained by the Infiniti dealer for the first 2 owners. I suspect this would be minimal - maybe a flush, but more likely not.

Then the transmission went climbing a long - maybe 8 miles long - constant grade on the highway at 60-70 mph. A planetary gearset gave up. That was a long period of heat generation. The dealer put in a new - not rebuilt - transmission with TC.

18,000 miles later we had the car and did a pan drop/screen change and installed the B&M external cooler BYPASSING the radiator tank one. Most here would agree that the radiator tank cooler actually keeps the fluid at 190 degrees (engine coolant temp) which is too hot for some of the transmission internals.

Since then the transmission has had the full flush with synthetic fluid about every 25,000-30,000 miles. We also put in a '93 TCU as, along with better performance, I think starting the car in motion using 1st gear is less stressful to the transmission. Touch wood, the transmission still feels like new at 135,000 miles.

I think it's possible your transmission sustained some significant heat damage in it's first 58,000 miles before you bought it. After your mods I would guess you may have lowered the temp by maybe 5 degrees, probably not more because the fluid is still flowing through the 190 degree radiator tanks - certainly an improvement over the stock set-up. If you bypass the radiator tanks completely you could drop maybe another 15 degrees. BTW, I have never noticed my transmission taking any longer to reach operating temperature than before the new cooler set-up.

I think you should now do a pan drop, screen change, external filter change AND full flush with the BG chemical & BG machine at the dealer. Have a good look at what comes out of the pan & screen and check how grungy the external filter is. Then completely bypass the radiator tank coolers. Some call them heat exchangers because they serve more to maintain 190 degrees rather than cooling as much as possible.

This may buy you some more time. I think many here would also agree that rebuild results are not always satisfactory (not a very long life) and, should the time come when you need to rebuild or replace, then you should really consider a factory rebuilt replacement before anything else (if you can still get one - call Joe at Scottsdale and check). They seem to last longer and perform better (or at least perform properly consistently).

Good luck to you.

Cheers,Glenn

[ericthered]

My '92 Q has about 194K on it. The 2nd to 3rd shift slowness when COLD started about 52K miles ago, right after a transmission oil change! After getting really worried for a while I thought of two things:

a) fluid expands as it get warmer....

b) prior to this change, I would add 4 quarts of ATF instead of filling until the dipstick indicated "full" on the dipstick. And generally top the level off 1/2" or so higher on the stick than "full".

So I added more fluid!

When I added fluid, the problem did not go away entirely, but got wayyyyy better, and the problem hasn't gotten worse since then, either. So folks here might say don't overfill your transmission because something bad might happen, but my own experience has been very good.

Note, this car does not have an extra cooler, and it has been used for commuting on mountain roads (9 miles up, 9 miles down twice a day) for most of the last 80K miles on the car. It is now my son's car.

An overfull transmission seems a lot better than a dead one. But as they say, your mileage may vary, maybe my dipstick is defective, I don't know, but doubt it.

Good luck.

[NightRiderQ45]

Where is everyone purchasing their synthetic atf? The Mobil1 atf fluid here (tulsa, ok) at autozone, advance auto are Mecron V. I need dex-3

[qship96]

There is no such thing as Dexron 3 anymore,all the dexron 3 licenses expired, replaced by Dexron 6. Dexron 6 is backwards compatable with Dexron 3, but starts out thinner,however it shears less with use than Dex 3.

The current Mobil 1 atf product is fine for your use.

[NightRiderQ45]

Oh, didn't know that it expired. Yeah, the bottle had Mobil1 bottle stated Mercon V, for use in GM cars. That scared me a bit, but if we can use it then it's purchased!

[drftard]

uhhh... i just finally joined NICO recently & have lots of problems with my 92' Q... 1 of them would be this included? im not sure if its the same but the symptoms are more of a rev up and the transmission tries to compensate... and also (i believe this happens b/c i have a nico ecu) when im in 3rd and going up a hill the transmission doesn't grab anymore & i have to shift down to 2nd to go up hills? my transmission has been replaced but is also used... my car could also just be going to sh tZ but i hope not... i just got it this year... any help would be much appreciated! i know almost nothing about Qz & cars! THANKS!

[JohnPa]

Hi John,

I think it's possible your transmission sustained some significant heat damage in it's first 58,000 miles before you bought it. After your mods I would guess you may have lowered the temp by maybe 5 degrees, probably not more because the fluid is still flowing through the 190 degree radiator tanks - certainly an improvement over the stock set-up. If you bypass the radiator tanks completely you could drop maybe another 15 degrees. BTW, I have never noticed my transmission taking any longer to reach operating temperature than before the new cooler set-up.

I think you should now do a pan drop, screen change, external filter change AND full flush with the BG chemical & BG machine at the dealer. Have a good look at what comes out of the pan & screen and check how grungy the external filter is. Then completely bypass the radiator tank coolers. Some call them heat exchangers because they serve more to maintain 190 degrees rather than cooling as much as possible.

This may buy you some more time. I think many here would also agree that rebuild results are not always satisfactory (not a very long life) and, should the time come when you need to rebuild or replace, then you should really consider a factory rebuilt replacement before anything else (if you can still get one - call Joe at Scottsdale and check). They seem to last longer and perform better (or at least perform properly consistently).

Good luck to you.

Cheers,Glenn

Glenn, thanks for taking the time to write such a thorough response, expecially during the Holiday season, which is my excuse for not responding until now. I also have the '93 tcu for a first gear start and I love it. Based on other posts, I was expecting a harsh 1-2 shift, but it is only firm.

The reason I used the heat exchangers is because my transmission works better when warm. I think the best idea would be an oil thermostat that would divert the flow after warm-up and the fluid reaching say, 180 degrees, from the radiator to an auxillary cooler like you have. That said, your experience in a similar climate is prompting me to go your route and bypass the radiator and use an auxilliary cooler. Great feedback!

I also plan to have the dealer do a flush using the requisite BG chemicals. I just had a normal flush last time and I really don't want to take any chances if I can save this transmission.

I am taking the car off the road for the next three months while I work on a number of maintenance items, not the least of which is a leaking sunroof seal letting water accumulate in the right rear floorwell. As soon as I get the transmission done, I will post the results.

Thanks again..................John

[JohnPa]

John, i don't think just replacing the valve body is going to do it.

as i mentioned in another post, you can compensate by forcing more pressure to the two functions of the 2-3 shift. this requires drilling out existing holes in the separator plate to a larger size. somewhat of a crap shoot though and there's no going back short of buying another plate.....

i compensated the factory 14ish ohm droppping resistor and am running about 35 ohm 40 watts. of course, this affects all of the shifts, not just 2-3.

best would be to buy a programmable TCU, whereby you could 'tune' each shift and map firmness to throttle position, etc.

i can't afford the $700 experiment right now.......

Great input that may save me a lot of money. The valve body and related soleniods would run between $600-$700!

Here's my current plan:

1) Buy the Subaru SVX Shift Kit from Small Car Performance in Tacoma, WA (done!)2) Locat the shift resistor, disconnect it, and see if the 2-3 shift problem goes away.3) If all of the shifts are improved without any of them being too harsh, I'm done! I'm most concerned with the 1-2 shift since I'm running a '93 tcu in my '90 Q.4) If the other shifts are too harsh, I plan to see if I can link the signal from the solenoid (I think there are two involved) used for the 2-3 shift to a new solenoid (switch) that will engage the SVX kit for that shift only. If I can't do this, well......back to the drawing board and I'm out $49.95 + tax for the kit.

Hey, if I have to go to step 4 AND it works, I might as well add a manual switch for 'sport mode' shifting when the harsher 1-2 and/or 3-4 shifts won't matter.

That's the plan............feedback welcome.............Thanks.............John

[3Q Jay]

i think all your shifts except the 2-3 will be intolerable with the dropping resistor open circuit. you will also get a 'trans malfunction' in the message center.i did this just to experiment, and i would chirp every 1-2 shift (engaging TCS in my case), even at 1/4 throttle.

the vac operated bypass relay may be a workable solution.

send me a PM if you want me to modify your valve body and change out the solenoids. i'll do it for beer money and materials, no guarantees other than i put it together properly.

[Infinitiguy19]

Have any of you tried the transmission check from the diagnostic display inside the q45?

I have this same problem and I did the transmission check and it came back ok.

[Q45tech]

Usually an ok on display just means electronics are functioning.

The mechanicals are tested on a transmission dyno or just following the proceedures in FSM as to internal pressures and shift time measurements.

The Consult has a specific section to report and test AT parameters where you can record shift times to the 0.03 second intervals.

Lubeguard Red offers improvements at least once in transmission lifetime....

I just usually replace the unit when it has worn too much.............that's why #3 AT has 102k now after 317k on the odometer. #2 was tired at 182k and was replaced.

[maxnix]

With regard to the title of this thread, one wonders if JohnPa understands the concept of operating temperature?

There is a performance envelope for all engineered devices, and the closer the device to the envelope's edge, the more performance detiorates until it will become inoperable.

[maxnix]

I bought the car at 91,000 miles and flushed the system, installed synthetic fluid, and custom fit a newradiator from the later Q's that has the extra cooling coil in the ends. It also has the extra external filter and a small copoling coil under the froint of the transmission. The car now has about 107,000 miles on it.

So, by "flush", do you mean a chemical flush like BG followed by a fulll mechanical exchange? If so, tell us about the appearance and smell of the ATF that emerged. What did the white paper towel test reveal?

Did you replace the old ATF with M1 ATF or some other synthetic (which?) ATF? If the former, did you add 6 oz. of LubeGuard Red?

The latter dual tanked heat exchanger is an improvement, over the earlier single tank, but the finned post 1991 Infiniti finned coil is a joke. If you are drving hills or over the passes a lot, consider adding an external B&M cooler like a 70268 or 70264.

Awaiting the details.

Oh, and let your car warm to operating temperature each moning upon a cold start. Kills MPG, but saves engine and parts long term.