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Yesterday my 4EAT ('88 GL-10, but figured best to post in new gen) trans went from perfect to sounding like a bad power steering pump (it's not the PS pump). It will make an engine speed related whirring sound that comes and goes. I thought it may be the torque converter but it still does it somewhat when I rev the engine in neutral, and also when the TC locks up on the freeway I can still hear it.

 

So that leaves the oil pump, as it's engine speed and not road speed or gear dependent. I removed my inline filter and looked inside, it was just fine. Checked the fluid (it's a few months old) and it's fine.

 

It looks like I can get to the pump after removing the diff housing. I'll probably upgrade to the newer housing as I currently have an adapter plate for my EJ20G, and it would be nice to get the newer torque converter.

 

My questions are thus: Why would the pump fail? Do I need a certain diff housing to use a Legacy SS torque converter?

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Something else that makes me think it's the pump is that when I pulled and replaced the filter, there was some air in the lines. When I started it in park, the noise became very loud for a second, the loudest ever, as I would imagine the air pocket reaching the pump.

 

I suppose it could be the flex plate or the torque converter. In any case I'm pretty sure the trans needs to be pulled to solve the problem.

 

It looks like I need to remove the pinion gear to get at the oil pump, which means removing the tail housing too. Has anyone ever replaced their oil pump?

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If it is the flex plate it might be visible through the cover used to access the torque converter bolts. On my H6 the TC is visible from below as well.

 

Usually pumps only fail when someone doesn't seat the converter all the way.

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I checked the torque converter bolts' tightness through the top access hole and I didn't see anything wrong. I did do an engine conversion a year and 10k miles ago, but I never removed the torque converter and the engine mated perfectly with no force. It's quite possible that the added power of the new engine has caused something to fail, but I can't think how more power would cause the oil pump to fail.

 

The surprising thing to me is how sudden this noise has shown up.

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Flex plates don't whine. They might click, tick, or knock, and will probably make you think a rod is about to sprout.

Probably the pump making noise. Pull the pan and check the pickup first. There is an o ring on the pickup screen that can let air get sucked in with the fluid and cause the pump to whine just like a steering pump will when the fluid is low. There may be another o ring higher up as well.

 

Also just for giggles check the torque of the bolts that hold the valve body to the case. I have heard of valve body bolts coming loose (don't remember which car it was) and causing some weird problems. If the bolts near the pickup are loose air could get sucked in around the valve body gaskets.

Edited by Fairtax4me
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The trans guy listened to it and he wasn't sure what it was either.  He said it was possibly the torque converter, but it wasn't consistent which made him wonder.  He said the oil pumps rarely fail.  He didn't think it was any kind of air getting sucked into the pump, as he said the inlet screen and valve body would normally be submerged anyway.

 

If I rev the engine in neutral and then shift to reverse with the RPMs around 2500, the trans is very loud and I can even feel vibration in the shift lever that coincides with the noise.  This also makes me think that it's not just sucking air.  I'm not sure why reverse is louder than drive, probably has something to do with the line pressure.

 

Anyway I guess I'll take out the trans and have a look at the torque converter first.  If I see anything obviously wrong I will just move forward with upgrading to the WRX torque converter.  Otherwise I'll dig deeper into the trans to see what's going on.

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The pan is perfect, as far as I can tell.  I ran a straightedge across it and it was flat.

 

I received the WRX converter, it looks like it will work.  I'd like to get the WRX turbine shaft too but I might have to settle for a normal one.  The WRX one is supposedly shot-peened for added strength.

 

I'm on vacation for a month so this will have to wait until I return.

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.

 

I suppose it could be the flex plate or the torque converter. In any case I'm pretty sure the trans needs to be pulled to solve the problem.

 

It looks like I need to remove the pinion gear to get at the oil pump, which means removing the tail housing too. Has anyone ever replaced their oil pump?

I've replaced the metal pump gasket. It was leaking. ( some shop had it apart and used a PAPER gasket in there!)

 

You will need a phase I bell and torque conv.

 

When you take apart. Pull the pan first. There is a washer behind the pinion shaft transfer gear that will fall off into the pan as you remove pinion shaft. It's a selective part to set pinion distance. Losing it is easy if you don't know it's there.

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  • 1 month later...

Thanks for the info!

 

I've torn it all apart, and the oil pump looked just fine.  I cut apart the torque converter and I noticed that the turbine had a bunch of play in the bearing, like 1/8".  The newer model torque converters have an additional bearing there along with the new shaft.  So hopefully that's the problem.

 

I looked for that washer on the pinion shaft but I couldn't find it; I see that it's there in the diagram on the older ones.  It seems the newer shafts like on my other '98 4EAT doesn't use a washer here.  The pinion bearing was perhaps a little notchy, and I can see by the wear pattern the R&P was not setup right by whomever rebuilt it.  There were no shims on the pinion, and it still needed to go further in, so I don't know what's up with that.  The rebuild was shoddy, I could see where they chiseled off (then reused) the pinion nut, etc., so maybe they just left that transfer gear shim off.  Anyway I've decided to just switch to 4.11:1 to help with the turbo lag, and because the old 3.7:1 pinion was worn funny.  I swapped speedo gears too.

 

I pulled the gear assembly from the '98 and put it in the '88 trans body.  I could see little upgrades here and there, and my clutches/band were fairly worn; the '98 one is JDM and looked great inside.  However I left the '88 low clutch as it had 6 plates vs 5.  Are there any hidden gotchas with doing this?

 

The newer trans had an anti-drainback valve fitted to the cooler line.  This should fix the occasional problem of the car not moving until the converter fills back up.  I swapped this to the old case, but I had to modify the banjo bolt as the old case had a deeper bore.

 

The WRX converter seems to fit just fine, along with the WRX turbine shaft.  I bought a new shaft as it was only $95 and supposedly stronger than the non-turbo ones.

 

After all this I guess I should have just moved the old valve body to the new case, lol!  Oh well.  Fingers crossed that it will work when I get everything back together!  Should be done in a few weeks, waiting on a few more parts.

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  • 2 weeks later...

Well it's mostly back together.  The speedo cable broke, the plastic was brittle from sitting next to the turbo, so I'm still waiting for that.  I ordered the newer style that's metal, hopefully it fits.  I also need to swap my LSD into the 4.11 R160.

 

I drove it anyway, FWD mode.  The whining noise is gone, and it shifts great.  It must have been the torque converter because the oil pump looked perfect, and I didn't mess with the valve body.  It now has the WRX torque converter.  Also I upgraded the rear mount to the newer '96+ style.  This meant I needed to use the newer tail housing as it's different than the old ones.  With the new mount the trans sits a little higher so the trans then hit the tunnel, so I "massaged" it.  A little more ground clearance I guess isn't bad.

 

 

Thanks for the suggestions guys.

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