Please tell me my transmission is okay

[SynisterQ]

I noticed when my car is cold, I'll put it in reverse and it goes in fine, but then when I back into the street and put it into drive, it just revs like its in neutral. I then shift to 1st and the car drives forward, then I shift to 2nd, and then 3rd and finally drive. Once this happens, I leave it in drive and it drives perfect. This only happens when the car is cold. I plan on doing a pan drop and refill with Redline ATF D4 within the week, so I hope this isn't a real problem. I did just drive it 800 miles home from Tampa without any problems at all. Please tell me that there is nothing wrong with my transmission, I'm so scared to hear your responses.

[Q45tech]

Transmission are really not designed to function very well until warmed to operating temperature just as high performance engines often object.

The AT has a temperature sensor which changes shift pressure to try to maintain reliability and smoothness.

When the fluid is old and dirty, the preprogram is wrong, when the transmission internal are worn the pump may not supply enough pressure or the pressure may leak away before it does the job.

JATCO trannies usually last thru warranty and if well maintained and not abused can last 200,000 miles. Time is important inthat 10 years is the functional equivalent of 150-200K.

All depends on when you go thru the 100,000 shift cycles not miles as city is 3-10 times worse than just interstates.

[oldmako]

So how long does one wait before driving away? Say on a 20-30defree F morning?? I try to give it a few minutes at least....until the temp needle comes off the peg and hits the first index. And I try not to allow the engine rpm above 1900-2000 till the needle is at half throw.

[Q45tech]

That's what I do, luckily I'm 2 stop signs, a school zone, and 2 red lights from interstate, so as I'm down the ramp merging I'm almost warm. This 1.5 miles takes 5-7 minutes so a 3 minute driveway warm up works perfectly. 10miles on interstate takes 9-10 minutes.

[oldmako]

To be honest, I never let any of my other cars warm up as long as I do with this Q. I'd give them a minute or two and just drive easy until they were at normal operating temp. I never really noticed any difference with them. Hell my truck was engineered in Michigan right? It's a LOT colder there so I never worried about it.

This car however is not the same. I notice that the transmission will not shift into the final gear until the temp is at least 1/4" of the cold peg. I assumed that this was designed into the box, but from what I have read here that may not be the case. My trans has 125K and while the fluid is clean and it shifts smoothly, I really have no idea of how it was treated since 1999.

I also notice that it "hunts and pecks" ever so slightly when decelerating to a red light and then when getting back on the gas prior to a full stop. It's very very faint, and I probably wouldn't even notice it if I weren't so paranoid about replacing it.

Thanks for the useful info

[SynisterQ]

Transmission are really not designed to function very well until warmed to operating temperature just as high performance engines often object.

The AT has a temperature sensor which changes shift pressure to try to maintain reliability and smoothness.

When the fluid is old and dirty, the preprogram is wrong, when the transmission internal are worn the pump may not supply enough pressure or the pressure may leak away before it does the job.

JATCO trannies usually last thru warranty and if well maintained and not abused can last 200,000 miles. Time is important inthat 10 years is the functional equivalent of 150-200K.

All depends on when you go thru the 100,000 shift cycles not miles as city is 3-10 times worse than just interstates.

So does this mean it is normal? The fluid looks super clean and smells fresh.

[maxnix]

So does this mean it is normal? The fluid looks super clean and smells fresh.

Tell us how it operates at normal operating temperatures.

[SynisterQ]

Tell us how it operates at normal operating temperatures.

When the trans goes into drive, it shifts perfectly fine, no slipping and maybe a slight hesitation. When I get on the throttle (once car is warmed up of course) it responds very well, and shifts like its supposed to. I noticed it takes longer to get into drive at my house because my drive way is pretty steep. However, last night, I was at the movies and watched two movies (temp was high 30s I believe) so my car was parked for at least 3.5 hours, I started it, let it idle in park for a minute, then shifted into drive, and it only took 30 seconds or less to engage. The movie theater parking lot is pretty flat so I'm wondering if this has anything to do with it.

[maxnix]

A 30° F, it should take about 5 minutes or so to reach operating temperature. Even then, only your engine and transmission casing by conductance is warm. ATF is cold.

Have you exchanged your fluid recently?

Drain and fills are mostly palliative, unless repeated several times in succession. By that time, your expense in ATF would exceed the cost of a mechanical ATF exchange.

http://www.bgfindashop.com

Get your parts from Joe.

http://www.infinitipartsusa.com

[SynisterQ]

I will do the 20 quart flush with Redline D4 ATF, in the near future, just wondering how I'm gonna store 16 quarts of ATF. I have access to a hobby shop on base at Camp Lejuene so that might be ok. Yikes, 20 x 9.00= 180 plus shipping plus a new trans filter. Do Nissan dealerships sell Infiniti Q 45 filters? The nearest Infiniti dealership to my house is 2.5 hours away. Might be a fun road trip though.

[oldmako]

A 30° F, it should take about 5 minutes or so to reach operating temperature. Even then, only your engine and transmission casing by conductance is warm. ATF is cold.

Not too sure that this is true on my '99 is it? Just looking at the tubes I think my transmission pumps it's fluid right to the radiator, (no aftermarket cooler.....purchased but not yet installed) so as the coolant heats up so does the ATF.....right?

My car goes from stone cold to half throw on the coolant temp gauge in 3-5 minutes at 1800-2000 rpm. And I have heat in the cabin shortly after as the thermostat opens up...so that tells me that my trans is only "cold" for a very short time. If I'm getting heat, so is the trans. Or no?

[maxnix]

http://www.infinitipartsusa.com

If you decide you don't want to muck around playing amateur pit monkey.

http://www.bgfindashop.com

Don't forget the extra crush washers.

[SynisterQ]

http://www.infinitipartsusa.com

If you decide you don't want to muck around playing amateur pit monkey.

http://www.bgfindashop.com

Don't forget the extra crush washers.

Not sure what you mean by the first comment but thanks for the help.

[Q451990]

Not sure what you mean by the first comment but thanks for the help.

Oh, that's just Brian's abrasive way of saying that it would probably be easier and almost the same price (since you'd only use 14 quarts of AFT), with marginally better results, having the transmission fluid exchange done mechanically vs. draining, refilling, draining, refilling, draining, refilling...

The A/T filter should be available from Nissan dealerships, as the 300ZX of the same era uses (I think) the same transmission. The P/N for the filter is 31728-51X08. It's O-ring p/n is 31526-41X07. And the pan gasket with new one-time-use bolts is C1394-51X90. I assume the 94 transmission uses the same filter and gasket as my 90. As far as I know the only difference is gearing.

Heath

[SynisterQ]

Thank you so much Heath for that wealth of info. I will use those part numbers to get the necessary parts.

[jmorasch]

infinitipartsusa will have the whole transmission kit in one package at the most reasonable price Ive seen...Im planning on doing the same thing to my 91 here soon. the trannys getting moody during start up take-offs in the morning. shes got 195k on it with a good maint, record. Im getting the same type of functions from mine.we are going through alot of temp, changes up here in k.c. and Ive noticed that the colder it is the more I notice this

[Skibane]

My car goes from stone cold to half throw on the coolant temp gauge in 3-5 minutes at 1800-2000 rpm. And I have heat in the cabin shortly after as the thermostat opens up...so that tells me that my trans is only "cold" for a very short time. If I'm getting heat, so is the trans. Or no?

Yep, the ATF passes through the radiator tank all the time, so as the engine coolant warms up, so does the ATF - but only after the thermostat opens up. Before then, the ATF gets no heat assist from the engine.

One possible approach to improving the transmission's cold shift characteristics would be to slap an electric heater on the bottom of the transmission sump pan. Heaters equipped with a powerful permanent magnet are available from some auto parts houses and industrial supply companies. Plug the heater into a timer that turns on several hours before your normal leave-for-work time, and the ATF and transmission internals should be much warmer by the time you start the vehicle. Adding an engine block heater would warm the transmission up even quicker.

[bullittandy]

This car however is not the same. I notice that the transmission will not shift into the final gear until the temp is at least 1/4" of the cold peg. I assumed that this was designed into the box, but from what I have read here that may not be the case. My trans has 125K and while the fluid is clean and it shifts smoothly, I really have no idea of how it was treated since 1999.

Thanks for the useful info

It is normal for the transmission to not shift into 4th gear until its warm. Its the kind of thing that you'd never notice until you live 10 seconds from an interstate on ramp (like me) and I got good at being able to predict when it would shift into 4th gear, on really cold days i'd be right at the Moreland Exit, but most days, the Glenwood Connector (references for the ATL folks).

I discovered this looking through the owners manual one day-made me feel better.

[SynisterQ]

Thanks everybody for your help, I feel so much better now. This only happens when I first start driving the car, once its warmed up, no probs whatsoever.

[q56er]

I've got a 93' Pathfinder and had a transmission flush at 100k miles. drove it another 10k and shifting began to deteriorate. Called several mechanics because I figured the jiffy lube had put the wrong fluid in. Both mechanics said it's probably not the fluid. What they said was putting fresh fluid in a transmission with that many miles on it will break down the coating on the clutch plates that develops over time. Kind of like carbon build up I guess. Anyway, before you flush the old fluid make sure you talk to a veteran mechanic. My problem turned out to be water in the fluid, possibly from a cracked transmission cooler inside the main radiator. Whether there is any truth to the fresh ATF breaking down the carbon coating is up for debate.....

[Q45tech]

Carbon coating........humbug!. How do these psuedo expert mechanics expalin how a transmission works well brand new? without a coating?

These old wive's tales are there to explain the magical vodoo that comes from lack of education.

Never trust everything a mechanic says as they like doctors only know the limits of their particular education. Do your own research!

When you don't spend thousands of hours studying [automotive technology] everything looks magical.

[SynisterQ]

Carbon coating........humbug!. How do these psuedo expert mechanics expalin how a transmission works well brand new? without a coating?

These old wive's tales are there to explain the magical vodoo that comes from lack of education.

Never trust everything a mechanic says as they like doctors only know the limits of their particular education. Do your own research!

When you don't spend thousands of hours studying [automotive technology] everything looks magical.

So, bottom line, cut and dried answer Q45Tech, are the transmission flushes that promise to get all of the old fluid out good or harmful? After all this reading, I still don't know the best answer to this question. There seems to be two sides, the side that swears by the total flush machines and then the ones suggesting the 18 quart fill and drain and fill and drain. I trust your answer but I believe you are in the latter camp. Can't wait for your response.

[ScottJackson]

New fluid/filter on a high mileage trans is GOOD! If the transmission fails shortly after a properly done fluid/filter change, it was coincidence. A lot of times a trans will start acting up so people put in new fluid and then it completely dies. It wasn't the new fluid that killed it. It was just right at the point of dying. New fluid MIGHT cause a leak if the old fluid was gummed up around a seal that was worn out anyway, but it takes a lot of abuse for auto trans fluid to gum up as it has lots of detergents in it to prevent that.