Transmission Faults (Signs of anything)

[overwest]

Heya, I was curious to know if the things that happened to me tonight are a sign of something bad lurking in the near future, or if it can be resolved with a simple tranny fluid drain and refill/filter.

So basically tonight, I was watching my tachometer as I was driving home, and I noticed after I would let off the gas, it would go from 2k, drop down once, drop down again, then idle at 1k. Also, I found that when punching the gas, on one occasion it went from 30-60 in the same gear. Furthermore, trying the same thing going up a hill, the car stayed at around 40mph and maxed itself at around 4k rpms. I'm really not hoping this is a sign that my tranny is going out but it just seems so. Thanks in advance for reading and your responses.

2001 Pathfinder 3.5
Auto Tranny.

[Towncivilian]

What's the level and condition of the transmission fluid?

1. Drive around for 10 minutes in the city after the transmission is at operating temperature.

2. Park on a level surface and apply the parking brake.

3. With P selected, shift through every gear and return to P.

4. Pull the transmission dipstick with the engine idling, wipe it clean, reinsert it completely, and read the level. It must be within the notched area labeled "HOT". Check for fluid contamination after wiping on a paper towel.

The fluid should be red, and not smell burnt.

[overwest]

Alright, I'll try that tomorrow and report back to you with the results.

[overwest]

 

So I guess I'll be doing a drain and refill sometime next week to see if it cures the problem. I took a video to while I was driving trying to duplicate the problem. The non shift issue was easy, went from 30-80 in the same gear maxing itself at 4k rpms. I couldn't duplicate the 2k-1k double drop though. I can upload it if you'd like it just takes awhile.

[Rebelord]

In the FSM, AT page 309 gives you the MPH and which gearing for given MPH whether half throttle or full throttle.

But here is a quick print screen of the chart.

[overwest]

So it looks like it's missing that shift from D2-D3? Or maybe I'm just not on the pedal correctly, not sure. It won't miss any shifts when you punch it.

Along with the fluid and filter change, would it beneficial to pour in some tranmission additive? Talked to the pops about it more and he said that a valve might be sticking.

[Rebelord]

At full throttle you will be in 2nd gear from ~30-60mph.

As for transmission additives. I have never been fond of them. I think of them more as a bandaid if needed.

Do your filter change, use the correct fluid see how it goes. If it continues to give you grief then have it diagnostic done at a reputable transmission place.

[Towncivilian]

Transmission additives other than Lubegard Red are worthless, in my opinion. Lubegard Red is well lauded by many transmission shops and is mentioned in some manufacturers' TSBs. I have about 20oz of LGR in my transmission, with the fluid being Castro Import Multi Vehicle, as well as a B&M 70268 cooler and a Mangnefine in-line filter.

 

The in-pan strainer should not necessarily need changing. It's more of a rock catcher and if it gets clogged, you have bigger problems. I would suggest a drain & fill or complete fluid exchange via the cooler return line using proper fluid. Nissan Matic D, Castro IMV (think it has been renamed to Transmax Import or something) or Valvoline MaxLife are all good options. You can find instructions on performing a cooler line fluid exchange in the linked thread in my signature.

[Slartibartfast]

You might look into a trans cleaner of some type before you flush it. I've heard good things about Seafoam Transtune but I've never had occasion to try it. I wouldn't leave it in very long but it might help make the crud come out with the old fluid.

[Towncivilian]

Seafoam Transtune is the same as the normal Seafoam. It's mostly solvent. I would NOT put that in my transmission, or my engine for that matter.