'97 QX4 Hard Shift 1st to 2nd, RPM's jump

[jeffreyachristensen]

200k miles. Great shape. But...
Can't figure this one out for sure. There's many posts on here about hard shifts, but can't find anything specific to my issue, so here goes. I'll give a typical scenario (in 2wd mode):
(1) At a stop. Press the gas normally to accelerate. Transmission knocks VERY hard from 1st into 2nd gear. Acceleration is very sluggish.
(2) Higher end of 2nd gear is pretty rough...can REALLY feel it if you touch the 4wd lever.
(3) Subsequent shifts are normal (no hard shifts)
(4) Acceleration is "lumpy". Not sure how to explain this. I can VERY slightly feel a hesitation, then go, then hesitation, then go. This variance happens about once per second. It feels as if I'm letting off the gas a bit every second, but I'm not. This is VERY subtle.
(5) RPM's stay fairly high for a bit, then kick down to, say 2500 at 60 mph. I'll go for awhile, then the transmission shifts down and RPM's jump to 3500 at 60 mph. It'll stay there for awhile, then kick back down to 2500 RPM. Eventually, it'll kick down to about 2100 RPM for awhile, then I'll see the needle jump a few hundred RPMS quickly up and down a couple times. Then it'll kick right back up to 3500. This is repeated. If I'm lucky, I get more time at 'normal' 2100 than at 3500.

This is fairly predictable based upon the following:
(1) If I accelerate a bit harder off a stop, the transmission doesn't knock hard from 1st to 2nd.
(2) If the transmission knocks hard from 1st to 2nd, I'm screwed and I get the typical scenario above.
(3) If the transmission doesn't knock from 1st to 2nd, I get a nice, normal shift sequence, and nicely settle to about 2100 rpm.
(4) But, If I go downhill for a bit, when the road levels back out, the RPM's jump to 3500 and stay awhile.

To sum it up, sometimes I get a good ride, sometimes it's all over the place. Help!

Gonna clean my MAF this weekend. transmission fluid is new. I've added Lucas Oil transmission fix to try and help. Any other ideas?

[m0nkeyprince]

well, first off, our qx4's 1st to 2nd shifts are known for shifting hard, i get that in mine too. though i noticed it shifting a bit better after i added a bottle of seafoam trans tune a bit before my transmission oil change.

second, if acceleration is "lumpy" or hesitant im sure seafoaming the engine might help . also new sparkplugs (if you havnt changed it yet) and a new fuel filter wouldnt hurt.

[ARKQX33V6]

1997 QX4 certainly goes through hard shifts from 1 to 2 and 2 to 3 but usually when the oils are cold. By the time the transmission is up to temp the oil is warmed and you can enter overdrive and shifting in all gears all the time is smooth quiet without incident.

But through 14 years of use: Change transmission oils regularly every 2 years, check your torque converter for lock up operation and you should know about how long you have to drive before your transmission allows final gear to come in based on temperature.

Colder ambients will cause longer wait times before the transmission warms up.

If your transmission displays erratic behavior at any temperature check your solenoid operation, cables etc. When you change oil inspect the old oil for grit, it should not be excessive. The oils should always be a bright pink, never dull or brown.

These transmissions are quite robust and trouble free but only if you keep the oils new. Check the transmission cover for leaks, and the tail stock for leaks. Lubricate the operating mechanisms at the top of the transmission and check the babjo fittings at the sides feeding the oil to and from the rad. If they are leaking open the banjos remove the crush washers and hammer them straight and wipe down the area and reinstall and test for leaking. If it still leaks new crush washers. Check the fittings at the lower rad.

If you are still getting hard 1-2 shifts check your throttle position switches with your actual throttle, you may have to verify your transmission pressures relative to operating speeds and loads.

[jeffreyachristensen]

Ok, I've seafomed the crankcase, cylinders, and gas tank. Changed the plugs as well. Changed the oil.
It runs MUCH better...smoother, +2 mpg, less RPM jumping... but I'm still getting occasional jumps.
The prevailing factor is still the 1st to 2nd shift. If it SLAMS into 2nd, I get jumping RPM's, or RPM's that stick at 3000 for too long before shifting into OD. If it shifts nicely, I'm in good shape.
ARKQX33V6, I'm not a gearhead, so some help please:
-How do you check the torque converter for lock up operation?
-How do you check solenoid operation?
-How do I check my throttle position switches and verify transmission pressures?
I'm not an idiot, so if it's at all a DIY thing, hit me. Otherwise, just tell me to go see a transmission shop.

Thanks for any help!!!

[Towncivilian]

I'd suggest that you drop the transmission pan to examine the condition of the magnet (checking for excessive buildup of ferrous material) and to replace the filter, as well as change out more fluid. Did you get the transmission flushed or did you do a drain and refill?

I'd also check for leaks along the lines leading to and from the transmission cooler and of course the pan and drain plug. If you drop the pan or drain and refill make sure to replace the crush washer on the drain plug (it's the same washer used for the oil drain plug - get one or several from a Nissan dealer) and tighten it to about 25 ft-lbs of torque. We have an excellent guide on dropping the pan here.

What happens when you hit the O/D off button?

[ARKQX33V6]

Towncivilian hit a critical point check the fluid!
The converter lock up takes place at a specified RPM and torque that can be "felt" as you drive, the tach should pinpoint this, but the solenoid shifts are going to take examination with pressure gauges. The TPS and intake work with transmission, if the TPS senses a particular high position then the transmission needs to react to give a certain gear for that position, if not, you get a code that tells you the TPS does not correspond to the gear.

If you have pulled the TPS off and replaced it you have the possibility of a bad connection and the result may be what is happening or a group of MIL codes come on that make no sense other than all the codes relate to transmission and out of range speeds.

When the transmission is cold so is the fluid and 1 to 2 are hard shifting but as you ease off the throttle the shifting should ease off till warm...but if no matter the throttle position you still get hard shifting:
check the TPS for actual positioning
Check the TPS for WOT switches actuating
Ensure the TPS connector is in the correct position

Also verify your transmission fluid is up to level and not over filled. If fluid is clean and new you should not need transmission medic in a can. Check your transmission cooling conduits from transmission to rad, the crush washers may be worn and fluid is leaking, but not enough to stain the floor but the transmission outer at shifter is wet and dirty.

Spend time under the QX4 with a very bright light. Check your MIL light for codes stored in memory.

If you find all this intimidating find a good transmission shop. Is the engine running as it should, idle at 750 RPM, when warmed, gears shifts on the level should go through all of them with a warmed transmission and try to do it with all shifts at or below 2000 RPM until 55 MPH, 60 MPH AT 2300 rpm, in OD.

It's easy to shift over 2000 but try and see if your X will do it at 2000, it will take a very light throttle and that will tell you more how the engine and throttle and transmission work. Then with the info you now stand a chance to resolve the shifting.

As a note the solenoids will become erratic in shifting with crap in the fluid causing the hydraulic end of the electrical solenoid actuators from sealing in and this in turn can cause the electrical solenoids to hold up close in and blow a fuse, but if they are dirty the seal in time can be slow, but not blow fuses.

Electro-hydraulic-mechanical actuators can and do depend on all aspects of control, with any one part being dirty shifting especially under higher pressures of hydraulic oil tend to be jerky.

A fluid change may clear the debris in, around and through the ports to cause smooth shifts. A peak at the filter or pan can reveal lots. It is normal to have some crap in the bottom of the pan, to keep it to a minimum change the fluid every 2 years.

[AZhitman]

Someone point him to the TPS diagnostic in the FSM.... I'm on my way out.

[jeffreyachristensen]

Thanks everyone! I'll try what I can do myself first.

Towncivilian: If the RPMs are normal, flipping the O/D button off makes them rev higher (as expected). If they're already high, it does nothing. That's the frustrating thing... if the RPM's jump up while crusing, no amount of button pushing, letting off the gas, slowing down, anything makes the gears "reset"...it sticks in that gear until it "decides" it's ready to shift, or until I come to a stop and give the gear sequence another shot from the get-go. And thanks for the link to changing the fluid- I can do that!
ARKQX33V6: Thanks for your expertise. I'll do some of the things you spoke of, and at the very least I have some "lingo" for when / if I bring it into a transmission shop.
AZhitman: I've got the FSM, so I'll look for the TPS diagnostic...thanks!

[jeffreyachristensen]

So I got fed up and took it to the Infiniti shop. It had this issue on the way to the shop.
I get a call from the mechanic a few days later... they can't duplicate the problem. I, of course, thought they were a bunch of idiots if they couldn't see the issue.
So I pick my QX4 up.... I HAVE NOT HAD A PROBLEM SINCE.... I have no idea if the Lucas Oil transmission fix finally did some good or what, but I'm trouble free... for now anyway!

[Silverhorn]

So I had this exact same issue. After reading about it a bit I decided to pull the transmission pan and change the fluid/filter. Turns out the majority of my problem was that the fluid was brown near the bottom. You can check with the dipstick and it looks red, but all the particulate sinks to the bottom where the dipstick doesn't really reach. My fluid had a milky white color near the bottom of the pan, as well as having a larg amount of particulate on the magnet. So if you are having this issue the first thing that I would do is spend the 40$ to replace your gasket, filter, and fluid (that's probably going to be less $ than a diagnostic fee at most shops) and should only take you about an hour (prob less time than taking it to the dealer and waiting for them to tell you nothing is wrong).

The issue was worst when the car was cold, and during the winter in general. But after some driving, and soft pedal work it clears up slightly. But when I finally gave in it was doing it routinely (whether warmed up or not). Stop signs were the worst.

After changing the fluid it performs perfectly. Every once in a while if you jump out on the gas while its cold it will still 'slam' into gear, but as far as I'm concerned you could do that to any car if you didn't let it warm up for a min or two before driving it.

I'm fairly new to this forum so sorry for reviving an old thread, but this looks like exactly the problem I had, and no one had posted a solution.

Nasty Magnet



As you can see the fluid looks nice and red, but in the above picture you can kind of see how dirty it is. It was nearly black once I emptied it into a clear container, far from the nice, clear, cherry red it should be. Long story short, don't trust the dipstick.