# 91 sentra XE A/T transmission problem



## 91nissansentra (Oct 25, 2007)

My 91 sentra XE A/T works pretty well with only 90k mileage. But there is a transmission problem. Sometime after I drive it for more than 30 minutes, the transmission just stuck in 2nd gear, not shift to 3rd and O/D gear. Once this happens, I have to turn off the engine and wait for 1 hour on the road to let it cool down, then it will shift well again. I changed the transmission fluid but no improvement.

Is it the problem of overheating of transmission? Is there a fan or sink for transmission heat dissappating on the radiator? Or any other reasons?

Appreciate for your help!


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## DA6GSR (May 5, 2005)

silly question but how is the tranny fluid? when was it changed last?


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## greenbean699 (Jan 18, 2004)

just another thing to check......pull the governor gear out to see the condition of it.


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## 91nissansentra (Oct 25, 2007)

I changed new tranny oil and no improve. This problem happens occasionally once the engine and transmission are heated, otherwise everything works pretty well. Once the problem happens, the gear will only works the 2nd. It's very frustrating since I have to wait on the curb of highway to let it cool down.


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## onlineidtim (Aug 20, 2007)

91nissansentra said:


> I changed new tranny oil and no improve. This problem happens occasionally once the engine and transmission are heated, otherwise everything works pretty well. Once the problem happens, the gear will only works the 2nd. It's very frustrating since I have to wait on the curb of highway to let it cool down.


My 91 nissan sentra does something similar. XE, 160k miles, 4 speed auto. When I don't warm up the engine or tranmission, the shifting is smooth (i.e. when I start in the morning or let it sit for couple of hours). However, once the tranmission gets warmer (after 5-10 mins of driving), it jerks/ shudders to shift while around 10-15mph, i.e. probably while switching from 1st to 2nd gear or 2nd gear to 3rd gear (I am not sure). Higher gear switching is fine. When I come to a stop and then accelerate, same thing repeats. However, if I give more gas, it kinda skips jerking, but not always. 

I noticed that the fluid is kinda brownish with burnt smell and also that fluid level was low. So, I added a quart of Valvoline Dex III Max ATF. Then again after a month or so, the level again seemed low, I added 1 quart of Castrol Multi Vehicle ATF. The fluid color now shows more pinkish but still smell a bit burnt. 

This makes me wonder if the fluids that I added do not have good properties at higher termperature. Could something like this happen to brand names like Castrol or Valvoline? Also, does anyone know of the quality of brandname called SpectrumPlus Multi Vehicle ATF (Manufactured by Warren Performance Products) sold at Sears Auto Center?

Related question is, what brand automatic transmission fluid (ATF) would you recommend/ have good experience with? (I searched on this forum with terms 'Transmission Fluid' and 'ATF', but in vain).

If someone has some advice or suggestion, can you kindly reply. Thanks in advance.


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## i r teh noobz (Apr 26, 2007)

My AT has Maxlife DEX III in it right now, no problems. If your tranny is burning and losing fluid.... do you see any leaks, or does it just disappear?


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## onlineidtim (Aug 20, 2007)

i r teh noobz said:


> My AT has Maxlife DEX III in it right now, no problems. If your tranny is burning and losing fluid.... do you see any leaks, or does it just disappear?


It does not appear that the car is leaking any fluid. I say this because I don't see it on the parking spot when I park over night or for longer periods of time. 

However, when I looked underneath, I noticed that neighboring parts had some dark semi-liquid substances. I am not sure whether the transmission is losing liquid while driving, or if the liquid is getting transformed into semi-liquid and getting deposited around. Of course, the liquid has gotto go somewhere because the level keeps dropping every 1-2 months or so. At this point (with my limited capacity in this area), I just don't know where its going.


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## onlineidtim (Aug 20, 2007)

onlineidtim said:


> It does not appear that the car is leaking any fluid. I say this because I don't see it on the parking spot when I park over night or for longer periods of time.
> 
> However, when I looked underneath, I noticed that neighboring parts had some dark semi-liquid substances. I am not sure whether the transmission is losing liquid while driving, or if the liquid is getting transformed into semi-liquid and getting deposited around. Of course, the liquid has gotto go somewhere because the level keeps dropping every 1-2 months or so. At this point (with my limited capacity in this area), I just don't know where its going.


In continuation of my previous post, it may be that the Transmission Oil Cooler Lines/Hoses are getting old with cracks and leaking? Where can I find new Transmission Oil Cooler Hoses and are they easy to replace?


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## Oldnissanguy (Jan 6, 2005)

There are two small lines attached to the bottom of your radiator that go to the transmission. Check them for leaks or hose clamps that need to be tightened.


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## i r teh noobz (Apr 26, 2007)

For both problems, I'd give the tranny cooler a good look. 91Sentra, your cooler lines may be plugged up for some reason, not letting the fluid in so it can cool. online, check your coolant. You might have a crack inside the radiator that's letting fluid escape into the coolant.


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## onlineidtim (Aug 20, 2007)

Thanks OldNissanGuy and "i r teh noobz" for the suggestions.

OldNissanGuy, I will check if the hoses are loose and tighten as necessary. Also, if need be, can I get new ones (at local auto stores) to replace while draining and refilling the ATF? Are the hoses expensive to replace?

"i r teh noobz", so, if the ATF is escaping into the radiator, (one possibility out of other scenarios non-obvious to naked eye) it might discolor the coolant also. I will check the color of the coolant.

In general, is drain and refill (2 times over a period of time to get liquid in the torque converter too) sufficient compared to full flush of the ATF?


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## 91nissansentra (Oct 25, 2007)

i r teh noobz said:


> For both problems, I'd give the tranny cooler a good look. 91Sentra, your cooler lines may be plugged up for some reason, not letting the fluid in so it can cool. online, check your coolant. You might have a crack inside the radiator that's letting fluid escape into the coolant.


After two tranny coolers installed in series following the radiator, the transmission works great and gear shifts smoothly. Thanks.


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