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How do you change the transmission filter?

35K views 28 replies 12 participants last post by  OmegaManEX 
#1 ·
On the RL4F03A (4 speed auto trans) how the hell do you change the filter?

Holding the filter is a bolt that goes all the way through the valve body with an attaching nut and washer on the other side. I just got through swapping valve bodies when I noticed the bolt is not even on the opposite side of the VB it’s sandwiched in the middle somewhere. WTF!

How does Nissan expect us to change the filter?
How would a mechanic even change that filter? This seams crazy if you ask me.

Can anyone shed some light on this?

Thanks
Seth
 
#2 ·
Replace

Before changing the transmission filter, review the recommended service intervals in the owner's manual and look at the vehicle's maintenance history.

Some transmissions have check balls, valves, and/or springs between the valve body and the filter or screen. Do not remove these. Pay special attention to these as you remove the filter. They can fall out and be lost.

Remove the filter and inspect it.
Filters are always replaced, whereas screens are cleaned.
Screens are removed in the same way as filters.
Clean a screen with fresh solvent and a stiff brush.
Make sure the O-ring for the filter was removed with the filter and not stuck on the housing.
Remove any traces of the old pan gasket on the case housing.
Then install a new filter and gasket on the bottom of the valve body and tighten the retaining bolts to the specified torque.
CAUTION
Make sure you check the specifications. The required torque is often given in inch-pounds. You can easily break the bolts or damage something if you tighten the bolts to foot-pounds.


Some transmissions are equipped with reusable oil pan and valve body gaskets.
Check with the service manual before you throw away the old gaskets.
Remove any traces of the old pan gasket from the oil pan.
Make sure the mounting flange of the oil pan is not distorted and bent.
Then re-install the pan using the sealant recommended by the manufacturer.
Pour a little less than the required amount of fluid into the transaxle through the dipstick tube.
Always use the recommended type of automatic transmission fluid (ATF).
Start the engine and allow it to idle for at least one minute.
Then, with the parking and service brakes applied, move the gear selector lever momentarily to each position, ending in park.
Recheck the fluid level and add a sufficient amount of fluid to bring the level to about 1/8 inch (3.0 mm) below the ADD mark.
Run the engine until it reaches normal operating temperature.
Then recheck the fluid level; it should be in the HOT region on the dipstick.
Make sure the dipstick is fully seated into the dipstick tube opening. This will prevent dirt from entering into the transmission.
 
#3 · (Edited)
Well put!

The part I find interesting is where you said, “Filters are always replaced, whereas screens are cleaned.”

Mine is a screen.
So then I shouldn’t be trying to replace it, I should be cleaning it instead.
Since I can’t remove the screen, because of that one bolt (check my first post), then I’ll be forced to clean the screen while it’s still bolted to my trany.
Well, I guess that’s possible. I just wish Nissan had made it a little easer that’s all. I mean, when I go to Shucks to buy a pan gasket, they always try and sell me the gasket/screen kit. Now I don’t need the screen, according to babyj, but I do need the gasket. Of course they don’t sell just the gasket and so I always end up buying the kit.
Something’s just plane fishy about this whole deal. Why do they even make a gasket/screen kit for the Nissan RL4F03A Transmission?
I believe given the circumstances the two parts should ONLY be made available as separates. It’s just my opinion but wouldn’t that make more sense.

Oh well! I'm selling the car anyway, hello SE-R!
 
#4 ·
Seth,

I see you now know what I was talking about when you picked up the transmission from me :D

It is a screen and not a filter. The only way to remove it to clean or replace it, is to remove the valve body.

When I went to replace it about a year ago (Not knowing then, what I do now), I took out all the bolts. When I went to bolt the new screen up, the one bolt would not thread in. I then realized I was SCREWED. After a quick look in the FSM I realized that the nut and washer were sitting on top.

So, I ended up removing the valve body and reinstalling the screen.

So, don't worry about it, because you are using my old valve body and the screen is fairly new. Plus, I did 2 flushes since then with the AMSOIL synthetic.

After discussing my fustration w/ a local Nissan mechanic, I now know the CORRECT way to keep a Nissan transmission healthy for a long time. Here is what he told me:

1)DO not change the screen. (His reasoning was that just removing and replacing the valve body HIGHLY increases your chances of dirt getting in the valve body and doing damage or damaging the valve body from other methods.)

2)Do a COMPLETE fluid flush every 30K miles.

3)Use synthetic ATF.

He said if you follow those directions, your screen should never need cleaning or replacement and the trans should last 2-300K miles fairly easily.

I followed 2) and 3) and my trans had over 150K on it when I pulled it for the swap and still was working good.
 
#5 · (Edited)
Haha… I thought you’d be chiming in here sometime soon!:D

Yeah, I’m not gunna change out your filter John, I just put the damn VB in and I’m not removing it anytime again soon.
You know just normal wear does indeed put a slight particle buildup on the screen. When you wipe the screen you see it’s there. From here on in I’ll just clean the screen as good as possible and call it a day.

Like I said, I’m moving on to a 200sx SE-R, and a whole new can of worms.

I’m almost sad to have to part with my 1.6 auto. She runs like a top and lately I’ve been adjusting that engagement switch you showed me. Man, my little auto gets up there now, it shifts right in the sweet spot for every gear and that gives me optimum performance…I love it!

Well, thanks for the help guys, I’m done bitching and complaining for awhile.

The over all solution to the problem is, remove your valve body to change the filter screen or... don’t try and change the screen…period!

Now if only the guys at Shucks would start preaching the word, instead of insisting you can remove the filter without removing the VB.
Live and learn!

Seth
 
#6 ·
i didnt know that transmissions had filters.....i only drive 5spds...maybe thats a sign...

sorry im a bored kid right now....good luck
 
#8 ·
This is what John showed me...
The throttle wire adjustment (on RL4F03A trans only) allows for adjusting the timing of engagement between gears. Undoubtedly you have noticed the stock settings force your trans to shift gears to soon. This sucks because I really like to ride out each gear to get some advantage of the higher RPM's.
So this can be fixed, at no cost, and it makes your trans feel tight and sporty.

1. locate the throttle wire adjustment
2. press the lock plate
3. slide the adjusting tube down about two clicks(down makes for more throttle before switching gears)
4. drive the car, notice the difference and repeat until the trans engages at just the right position. You'll feel it!

Don't over do it!



 
#9 ·
Thanks for the informative post! :)

Just a point of clarification:
1) Does that mean it changes the shift points for ALL gears??

I think this adjustment is timely cos I've just installed an Edge Racing Torque Converter (stall speed of 3.2K rpm). So I do need shifts higher than normal...;)

Thanks again!!
 
#13 ·
Alright, after playing with it a little I figured it out. After doing a few runs, it seems the tranny still shifts at the same rpm during WOT, but during part throttle there is definately a difference. Specifically the shifts are harder and at a higher rpm. I set it at the lowest point and now it shifts 500rpm furthur from where it was. While it feels good, the harshness is a little worrysome. Is there any reliability(longevity) issues associated with having the tranny shift as hard as possible? Why is the tranny shifting harder(besides the fact that the adjustment has been changed)?
 
#14 ·
After even further adjusting, I have it so it still shifts at 3500rpm(instead of 3000rpm like it was) with firm, direct shifts. It's not harsh anymore, just firm and authorative. Oh yeah, I also read and found that it works by increasing the throttle line pressure or something like that. Anyways, thanks for the tip on this free "mod," heheh:)
 
#15 ·
Hey glad to help!:D

I’m also glad you did some research!!!
I don’t know all the pros and cons of this mod, but I really love the way my auto trany shifts now.


If you find more info about this mod and what it does please post some links here...

I'm always interested in learning more.

Thanks
s
 
#16 ·
Well, according to a chiltons manual, there's hydaulic pressure in the tranny that's controlled by two variables: vehicle speed and throttle position. Pressure is increased as vehicle speed increases. Pressure is also increased by opening the throttle wider. By tightening the throttle wire(by doing the little adjustment), pressure is increased as if the throttle was opened more than it really is. With increased pressure, the shift points are delayed. To a certain extent delaying shift points makes better use of the available power as shifts occur at a higher rpm where more power is available. This information might not be 100% correct, but it's something at least:)
 
#18 ·
barnoun said:
Well, according to a chiltons manual, there's hydaulic pressure in the tranny that's controlled by two variables: vehicle speed and throttle position. Pressure is increased as vehicle speed increases. Pressure is also increased by opening the throttle wider. By tightening the throttle wire(by doing the little adjustment), pressure is increased as if the throttle was opened more than it really is. With increased pressure, the shift points are delayed. To a certain extent delaying shift points makes better use of the available power as shifts occur at a higher rpm where more power is available. This information might not be 100% correct, but it's something at least:)
yeah that is right. the only other way you can play with the line pressure is having the valve body recalibrated... Seth, can you let me know how much shipping for the valve body is?
 
#19 ·
I'm also interested in an upgraded valve body, having just installed a performance torque converter.

However, I stay in the Far East Asia (but happen to be in US just for this week - staying in LA now).

So would be grateful if you could tell me where to purchase such an item, its price and the corresponding contacts....

Thanks! :)

BTW: By doing the adjusting tube mod, would that be similar to tightening the throttle cable by adjusting the nut?
 
#21 ·
ok im back after 5 min's of driving around, and all i can say is: This free mod rocks!!:D!!
i adjusted mine 1 click down and the shift points have raised about 5-700 rpm for every gear.

and to just make sure there are no severe long term effects of this mod right? as long as i keep it at my 1 click setting?


... hmm when did the topic of this thread changeover , hmm...
 
#23 ·
PrOxLaMuS© said:
you may need another transmission cooler... becuase that build up of pressure can cause heat and distress to your tranny. So head on out, and get an auxilary tranny cooler to save the life :)
Actually it is quite the opposite. With lower pressures your shifts happen sooner and softer. The softer shifts are actually soft because the clutches are slipping. This slipping increases friction and heat and will decrease transmission life greatly. By adjusting the cable to give shifts at higher RPM's and pressures, the clutches grab instead of slip, thus INCREASING transmission life by reducing friction and heat. Only drawback is some people don't like the harder shifts.
 
#25 ·
johnand said:
Actually it is quite the opposite. With lower pressures your shifts happen sooner and softer. The softer shifts are actually soft because the clutches are slipping. This slipping increases friction and heat and will decrease transmission life greatly. By adjusting the cable to give shifts at higher RPM's and pressures, the clutches grab instead of slip, thus INCREASING transmission life by reducing friction and heat. Only drawback is some people don't like the harder shifts.
Exactly, you're the shit!
 
#26 ·
johnand said:
Actually it is quite the opposite. With lower pressures your shifts happen sooner and softer. The softer shifts are actually soft because the clutches are slipping. This slipping increases friction and heat and will decrease transmission life greatly. By adjusting the cable to give shifts at higher RPM's and pressures, the clutches grab instead of slip, thus INCREASING transmission life by reducing friction and heat. Only drawback is some people don't like the harder shifts.
hell yes, I agree. only draw back--- bad mileage... which isn't that bad but unavoidable.
 
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