Trans Slipping?

DavieGravy · #1 09-16-2002, 01:12 PM

I was on the highway today. I slammed the gas at about 70. The lower gear took a while to engage. At first, I thought it was being it's usual indecisive self, but then I noticed continuous vibrating/shuddering through the car that lasted about 2 seconds before it dropped into lower gear. The car has no other symptoms, nor was I able to reproduce this problem. Could this be a serious concern. I don't have the money to replace the transmission and I can't be left without a car. If it's the tranny, I'll sell the car without thinking twice about it. BTW tranny has approx. 25k on it and has had it's fluid changed recently. It was cooked after 20k.
Another thing, the trans was replaced within the last 2 years. It was the updated version with the new gaskets. How long do the updated transmissions usually last? I've tried to do a search on this, but I couldn't find anything.
Thanks.

dromano · #2 09-16-2002, 07:08 PM

suggest you have a top notch tranny shop test drive your SVX for an evaluation

DavieGravy · #3 09-17-2002, 10:03 PM

I'll do that. Thanks. BUT!!!!!!
How long do the updated transmissions usually last?
Anyone?
Anyone?
Anyone?

svx_commuter · #4 09-18-2002, 11:30 AM

That I think will depend on how you drive and maintain it.

DavieGravy · #5 09-18-2002, 01:19 PM

But do they last longer than the originals?

DavieGravy · #6 09-18-2002, 09:54 PM

It's funny. I've been using this site for over a year and I've never heard of this being brought up. According to the place that installed the tranny, the new ones last well over 150k. For some reason I doubt that's true. If anyone has any knowledge on this I'm eager to hear your input.
Thanks.

oab_au · #7 09-19-2002, 07:01 PM

Quote:

Originally posted by DavieGravy
It's funny. I've been using this site for over a year and I've never heard of this being brought up. According to the place that installed the tranny, the new ones last well over 150k. For some reason I doubt that's true. If anyone has any knowledge on this I'm eager to hear your input.
Thanks.

How long will it last ?

That depends on how well the rebuild was done in the first place.
Did they just fly in and replace the obvious bits, or did they recognise the cause of the failure and fix the problem????

The auto box had a number of teething problems

. The one that has caused the most grief, is the facings that were used on the band and clutches. These facings were used by many other auto box makers with the same results of flaking, where small pieces of facing come off, to end up in the oil.

The SVX trouble stems from the lock up clutch, that is on the torque converter. The facings flake off and because the torque converter produces the major amount of heat, It's out flowing oil is sent to the cooler in the radiator. The cooler tube has a bronze mesh through it to improve the heat dissipation by conducting heat from the middle of the oil flow.

A good design but not when pieces of facing come down from the lock up clutch to lodge there blocking the flow. The end result is over heating of the oil and because this cooled oil is used to lubricate the gear train, gear set melt down resulted.

The smaller pieces that got through the cooler, then lodged in the passages leading to the gear set and even in to the main shaft itself, clogging it up. If the box is then overhauled and the lube problem is not diagnosed, the blockage remains to repeat the gear failure.

I think the facings were changed sometime in 93, But as the larger production run was of 92/93 models, the problem is wide spread. Subaru added a filter to remove the bits and removed the mesh in the cooler tube, to stop the blockage there, but by this time the bits could already be lodged in the box passages.

What was needed was a course mesh filter before the cooler to remove the larger pieces to prevent the blockage. Fitting a very fine filter, though it may seem right, can restrict this low pressure flow.

So if the box has been overhauled by a competent person all modifications have been carried out, The cooler has been cleaned out, you should have a bullet proof auto, as the later models are.

The shuddering that you had when it went back to third is something slipping, in third all the gears are selected to lock the box up to a 1:1 ratio. I reckon it could be the band needing adjustment. But as you say "it was cooked after 20k", it may be too late, the high clutch and gearset may be 'rat ****' (technical term meaning money).

Anyhow thats the way I see it mate.
Harvey.

svx_commuter · #8 09-20-2002, 06:23 AM

As a short term fix you may try removing the resistor by the battery. It will put the line pressure at the max all the time. It may be your line pressure curcuit is sticking. The shift form 1st to 2nd may get rough.

DavieGravy · #9 09-20-2002, 01:14 PM

Quote:

Originally posted by oab_au

How long will it last ?

That depends on how well the rebuild was done in the first place.
Did they just fly in and replace the obvious bits, or did they recognise the cause of the failure and fix the problem????

The auto box had a number of teething problems . The one that has caused the most grief, is the facings that were used on the band and clutches. These facings were used by many other auto box makers with the same results of flaking, where small pieces of facing come off, to end up in the oil.

The SVX trouble stems from the lock up clutch, that is on the torque converter. The facings flake off and because the torque converter produces the major amount of heat, It's out flowing oil is sent to the cooler in the radiator. The cooler tube has a bronze mesh through it to improve the heat dissipation by conducting heat from the middle of the oil flow.

A good design but not when pieces of facing come down from the lock up clutch to lodge there blocking the flow. The end result is over heating of the oil and because this cooled oil is used to lubricate the gear train, gear set melt down resulted.

The smaller pieces that got through the cooler, then lodged in the passages leading to the gear set and even in to the main shaft itself, clogging it up. If the box is then overhauled and the lube problem is not diagnosed, the blockage remains to repeat the gear failure.

I think the facings were changed sometime in 93, But as the larger production run was of 92/93 models, the problem is wide spread. Subaru added a filter to remove the bits and removed the mesh in the cooler tube, to stop the blockage there, but by this time the bits could already be lodged in the box passages.

What was needed was a course mesh filter before the cooler to remove the larger pieces to prevent the blockage. Fitting a very fine filter, though it may seem right, can restrict this low pressure flow.

So if the box has been overhauled by a competent person all modifications have been carried out, The cooler has been cleaned out, you should have a bullet proof auto, as the later models are.

The shuddering that you had when it went back to third is something slipping, in third all the gears are selected to lock the box up to a 1:1 ratio. I reckon it could be the band needing adjustment. But as you say "it was cooked after 20k", it may be too late, the high clutch and gearset may be 'rat ****' (technical term meaning money).

Anyhow thats the way I see it mate.
Harvey.

Harvey, thankyou very much for taking the time to post such a detailed explanation on this. I'm glad that I fainally understand the whole picture.

When I said the fluid was cooked after 20k, I was probably over exagerating a litlle bit. It was definately in need of change though. And that 20k could have been closer 25 or even 30k. I'm not exactly sure.

It's still shifting normally, so hopefully the gear set hasn't been destroyed yet.

From this point on, I'll keep an eye on the colour of the fluid. If I notice it starting to change in a short amount of time, I'll probably take it in and have it looked at. I may take it in anyway to ease my concerns. I'll mention to them that the cooler may not have been flushed out as well as the other issues you've brought up.
Thanks again,
Dave.

Quote:

As a short term fix you may try removing the resistor by the battery. It will put the line pressure at the max all the time. It may be your line pressure curcuit is sticking. The shift form 1st to 2nd may get rough.

I've tried doing this and I didn't like the hard shifting. For this situation, I don't think its relevent anyway, but thanks for bringing it up.

Dave

mattski · #10 09-20-2002, 01:40 PM

Quote:

Originally posted by DavieGravy
I slammed the gas at about 70.

I don't have the money to replace the transmission and I can't be left without a car

Davie, I respectfully submit to you that these two statements are mutually incompatible. If you cannot afford major repair bills, it would be prudent to drive the car gently. In addition to the transmission, your wheel bearings and tires will be grateful.

Matt

Paisan · #11 09-20-2002, 01:45 PM

I did some research and found somewhere (forget where) that on upshifts the computer turns off 1 bank of cylinders to produce smoother shifts. When I first started driving the SVX I found myself lettingoff the gas during upshifts which messed with the computer, now I just plant my foot and it works better.

-mike

sfsvx · #12 09-20-2002, 02:42 PM

Quote:

Originally posted by oab_au

The cooler tube has a bronze mesh through it to improve the heat dissipation by conducting heat from the middle of the oil flow.

Harvey,thanks for that very clear description. It's ironic that Subaru chose that transmission because they didn't have a manual that would handle the power.

I've thought about the possibility of locating that mesh screen and removing whatever's on it.

Is that possible? Desirable? Stupid?

svx1999 · #13 09-21-2002, 04:53 AM

Hello
No your question of removing the Filter mesh is not stupid.
Since that was a HOT spot for the 92's.. Seems rather logical.

However to get the wire mesh out I believe you have to replace the radiator with a New one...

I don't know if anyone has removed one. I spoke to a Very knowledgable trans guy in CA.. He said the Mesh was a lot finer then you would think.. That even cleaning it would not fully get all contamination out.

That is why serveral have By pass the Cooler line in the Radiator and send it to a second aux cooler.. This does have it's own draw backs if you live in a colder climate.
It will take the Transmission a little longer to warm up.. The trans has to be at a certain temp before the shift to 4th gear will take place. I think it's like 150 degree's coul dbe wrong.

IF you have a 92, and Either your transmission has been replaced serveral times or is the orignal.. You may want to consider a Second cooler. Maybe even bypassing the radiator based Cooling line.
That would ensure you have proper flow. consider this rather seriously.

THis cooler line is over looked best I can tell.. After 3 tranny's I still had the original radiator.. NO one mentioned that the problem was ever based there.

There seems to be a pattern of failure with the 92's.
I replaced my radiator soon after buying the car just to rid myself of the possible problem line.
best of luck
SVX1999..

Landshark · #14 09-21-2002, 05:15 AM

cheaper to just bypass stock cooler and get an aftermarket one. they are around $50 and up.

sfsvx · #15 09-21-2002, 08:05 PM

I'm taking it in next week for the tranny cooler - I have the maintenance records, and as far as I can tell, it's the original tranny. The original owner bought the car when he was 65, so I don't think it was mistreated. The filter mod was done a few months after he bought it, so I'm guessing that the flow through the radiator is still pretty good. I do intend to replace the tranny filter, just as a precaution, even though it is good for eternity.

I was thinking also about looking at the mesh screen as a diagnosis tool, as well as cleaning it just so it would be clean. I'm not ready for a new radiator yet, so I'll just do the cooler and new filter.

Thanks for the answers, svx1999 and Landshark.