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Symptoms caused by a dirty tranny filter.


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I'm not sure on this but I think if you had a dirty filter it might not even shift into gear, or it would have difficulty getting into gear and then shifting between gears from there on. I think you have wear issues if it's slipping once in gear.

 

I'm just starting to really learn about automatics so lets everybody tell me if I'm wrong! :drunk:

 

Keith

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I’m with Keith on this one, in my experience a plugged filter likely to cause shifting issues long before slipping issues, slipping in gear is more likely worn clutch packs. If you plan on rebuilding it, sooner will be better than later, the longer you let it slip the more heat and damage it will do to other parts.

I learned the hard way on the trans in my Suburban, I knew it was going but figured the cost would be the same if I drove it tell it really broke… not true. What would have been about $1500 in wearable parts became a shattered sun gear/shell, planet gears and hub… $2500.

Gary

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Change the fluid and filter and see if it improves. It's not hard, or expensive and could prolong the life of the tranny a fair bit.

 

I've heard those sun gears shatter. Real unhealty noise. I just figured that auto trannys would just keep slipping till they couldn't grip any more, but wow what a bang when you floor it while its slipping. And a nice ripping, grinding noise as the remains dissapear.

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Change the fluid and filter and see if it improves. It's not hard, or expensive and could prolong the life of the tranny a fair bit.

 

I don't want to hijack this thread, but its intersting you say this. I've had several mecahnics say that if an automatic starts slipping it is best to keep the old fluid in. They say that changing to fresh fluid would actually make the problem worse. My friend was told that by a Subaru dealership mechanic when dealing with slipping in a 99 Impreza. I don't understand why this would be.

 

Keith

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I don't want to hijack this thread, but its intersting you say this. I've had several mecahnics say that if an automatic starts slipping it is best to keep the old fluid in. They say that changing to fresh fluid would actually make the problem worse. My friend was told that by a Subaru dealership mechanic when dealing with slipping in a 99 Impreza. I don't understand why this would be.

 

Keith

 

I have heard the same thing. Luckily I don't have this problem with my Legacy, but I DID with my old Protege.

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But it only slips giong from park to forward or rev. after the tranny is warmed up. when it is cool it is fine. Any ideas? But once I am moving I can step on it or do whatever and it works fine.

I do not have a manual that covers the 4EAT, but I assume that it has a forward/reverse band? Has this band been adjusted?

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But it only slips giong from park to forward or rev. after the tranny is warmed up. when it is cool it is fine. Any ideas? But once I am moving I can step on it or do whatever and it works fine.

 

Well that sounds a bit different than what I thought based on your first post.

 

That said questions:

Have you payed attention to the RPMs between shifts?

When cold do the RPMs go up between shifts?

When hot do the RPMs go up between shifts?

 

I've test driven a few cars for people where this was the case and this is what I've learned. There is a seal or O-ring on the oil pump (not sure if thats the right term) in the trans and when it goes bad it gives you the above symptoms. What happens is when cold the seal actually seals correctly, but once it gets warm the seal expands and no longer seals correctly and loses pressure. So, the trans shift fine when cold, but once warm it will slip between shifts. I'm not sure where this seal or O-ring is, or how hard it is to replace, but I think that could be your problem.

 

Keith

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I do not have a manual that covers the 4EAT, but I assume that it has a forward/reverse band? Has this band been adjusted?

Have not adjusted the bands. Dont know where there are. What do the bands do? When cold the tranny will still slip in the first gear just when taking off. Once your going it is fine. When warm it is just a little worse. Just in the fist two gears though. Whe shifting from first to sec it doesn't want to seem to engage. It just takes it time. Revs out then goes in to gear. After these two gears the rest are fine. It seems like once it builds up enoguh pressure it is fine. But still what do the bands do?

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Have not adjusted the bands. Dont know where there are. What do the bands do? When cold the tranny will still slip in the first gear just when taking off. Once your going it is fine. When warm it is just a little worse. Just in the fist two gears though. Whe shifting from first to sec it doesn't want to seem to engage. It just takes it time. Revs out then goes in to gear. After these two gears the rest are fine. It seems like once it builds up enoguh pressure it is fine. But still what do the bands do?

OK. I checked in my service manual about the brake band. It says to turn the screw 1/4 of a turn counter clockwise if these symptoms are happening. And this matches the desription to a tee pretty much, Jolts when shifting from 1st to 2nd.- engine speed udruptly arises from 2nd to 3rd, -shift delays in kickdown from 3rd to sec- car slips from 1st to 2nd. I need to put the car up on stands and turn this damn screw, Hopefully this is the fix.

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