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Bad Torque Converter? [Was: Bad CV?]


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22 replies to this topic

#1 yarikoptic

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Posted 06 July 2007 - 02:07 AM

Hi All.

After I cried before http://www.ultimates...ad.php?t=72752,
and now changed both front CVs to new ones (china made, but AC DELCO "approved") at once, vibration at 20mph remained. And actually within time it evolved into: at 20mph it is very prominent, especially if going uphill; vibration is present at any other speed when accelerating (ie putting more load), even at 70 or 80 mph (though less prominent higher the speed); at 20mph if going up to quite a steep heel you can feel/sound even bang-bang (not too loud but defintely smth hitting smth) if that vibrating condition is sustained for long enough

Today, I've "rented" a mechanic from one of the local dealerships, and he
1. 100ft after driving start said "this car has no power" (this is LL Bean so 3L 6 cylinders and he has baja with 6 cyl, he says it flies... apparently I got used to be too gentle). And that the engine sounds fine (I also changed sparks plugs recently... How could they screw up such an easy job to do -- on 6 cyl it is quite a hand twisting task
2. 1mi after driving said "I think I know the problem"
3. after 2mi he said "it is the torque converter".
Meanwhile I was blurbing that CVs got changed, that differential fluid was changed and I saw quite a bit of residue on the plug, etc

so the first question how viable is that cause of vibration? is there any way to support or rule out torque converter (TC) as the cause?

Another part of the question would be how viable is to replace the TC if I find a "friendly" garage with tranmission jack? (I guess I should not try to pull out whole engine assembly on this 3L monster...?) I've done occasional car fixes (now I think I can change CVs shafts with closed eyes): head gasket change on Dodge neon, crankshaft sliding bearing inserts replacement on Nissan, CVs on Subies, wjeel bearing on subi, and less involved ones (brakes etc).

Since it was vibrating is there any bearing I should watch out and have it replaced? (I don't think that there is any, and I want to stay as far from taking AT apart -- asking just to make sure)

Anything else which should be replaced (ie bought in advance along with TC) along the way of replacing TC?
Front gasket (is there any bw AT and engine)

I have read a bit on what to watch out and how to seat the converter properly (useful threads Seating the Torque Converter Properly http://www.ultimates...ead.php?t=71493 , Torque Converter Question http://www.ultimates...ead.php?t=71831,
Amount of time/work involved in pulling auto tranny '98 OBW? http://www.ultimates...ead.php?t=71358)
but before I try it remains the "dry knowledge"

I'm sorry for too many questions at once but I would really appreciate the feedback.


#2 porcupine73

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Posted 06 July 2007 - 05:36 AM

If you have the tc done, they either have to pull the engine or the trans. If they pull the trans, have them check the driveshaft. Looked like many people thought that was the issue in the other thread. Maybe you already had it checked. It does still spin even with the FWD fuse in, and if any of the joints are slightly frozen or loose it's still going to vibrate.

If the tc is replaced, replace rear main seal. Replace rear main seal retainer/oil separator plate with a metal one if it is plastic (but that's an H6 so maybe it's different). Reseating the tc can be tricky. It must be seated fully and the bolts cannot simply be drawn down to try to push it in as it could crack the pump.

#3 grossgary

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Posted 06 July 2007 - 07:36 AM

did this start happening randomly or after any particular service, maintenance, incident, etc?

i've personally had brand new axles from the parts store explode to pieces and know of others that have had them be noisey, vibrating, and leak grease, i don't know what i'd do. but i'd want to rule out those axles for sure before yanking a transmission. if the vibration is identical to before then i guess that basically rules out the axles since it would too coincidental to have the exact same symptoms from different axles. just make sure it's indeed exactly the same. you're sure that axle was changed? i know people that have accidentally reinstalled the old part...thinking it was the new one and realized it after the fact. long shot...but heck, so is a subaru torque converter failing.

what you say about the driveshaft makes sense, but i'd want to pull it off and have a look. they are rather easy to remove. it has to come off to drop the trans anyway, so they can remove it and inspect the ujoints then at least.

first step is to check all the torque converter bolts. there is an access hole where they can be inspected and retorqued without any real work being done.

i know subaru torque converters can fail, but it is very, very rare. there really isn't much to a torque converter, it's a big hunk of metal with vanes inside. i'm not even sure how they fail exactly, i've never heard of or seen a subaru torque converter fail. there is a snap ring that holds the shaft to the torque converter, don't know about your newer model, but typically 4EAT's have a ring seal around one of the shafts as well and there's a torque converter seal too. i would be prepared to inspect and replace those while it's out. i would also have those shafts that slide out of the trans inspected, just to make sure they're not bent or anything. i'd be completely paranoid to get into a job this big and not have the issue resolved once it's done....particularly if i was paying someone else to do it.

#4 Skip

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Posted 06 July 2007 - 07:47 AM

I have a simple question.

how crediible is a mechanic that says
"he has baja with 6 cyl"

??

I'd get another opinion.
TC are expensive and the labor is equal to or exceeds this cost.


This sounds more like a DOJ problem than a CV.

#5 nipper

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Posted 06 July 2007 - 09:38 AM

Real simple TQ test (which i am shocked the mechanic did not do).

Set the parking brake
STAND on the brake pedal
Put the car in D
Floor the gas (NO LONGER THEN 2-3 seconds).
Read the peak number on the tach and tell us what it is. This is the stall speed test.


Here is TC 101
http://www.autoshop1.../forms/AT02.pdf
(they all work the same way).

it is so RARE for a TC to go bad in soobie, i would look at the cat before the TC.

Disconnect the Y pipe at the engine and go for a short drive, wee if there is a difference in performance.

nipper

#6 yarikoptic

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Posted 06 July 2007 - 11:19 AM

I have a simple question.

how crediible is a mechanic that says
"he has baja with 6 cyl"

Well -- I did not know much about Bajas and I could have misheard about Baja. Indeed it seems that commonly they come with 2.5 (with or without turbo), but at least here
http://trucks.about..../a/baja_epa.htm
it list fuel economy for a baja also with 3.5L one (6 cyl), so may be there is some 6 cyl model?
and I would not be surprised much if he swapped default 2.5 with 6 cyl one (as the prototype of baja had)...

I'd get another opinion.
TC are expensive and the labor is equal to or exceeds this cost.

indeed - he said that dealer would charge about 400 for parts and 600 for labor.

This sounds more like a DOJ problem than a CV.

As I mentioned -- I already swapped CVs quite a bit:
1. left one was replaced with new -- problem persisted
1.1 alignment, transmission flush -- problem persisted
2. old left one (regreased) was placed in place of the right one -- problem persisted
3. changed both cv axles with brand new ones (so I am sure that I didn't put any old one on) -- problem persisted

Problem was pretty much the same across those actions... only that at some point it evolved a bit. Previousely I didn't feel any vibration at speeds other than 20mph; then sometime between 1 and 2 I started to feel vibration while applying torque at higher speeds (60-70, etc) and it got a bit less wild at 20mph. Problem did not change a bit by doing 3. -- just subjectively I would say that it became a bit "sharper" vibration -- may be due to tighter joints some vibration also got to wheel or smth. But it is really subjective and may be "normal" evolution of the problem.
now I am off to do stall test ;-)

#7 yarikoptic

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Posted 06 July 2007 - 03:15 PM

good/bad news -- stall tests (at 2, D, R) showed normal rpms -- around 2250rpm -- service manual says normal range for 3L 2000-3500 rpms. So I guess it transfers torque fine (unless transfer deteriorates while smth vibrating). And lack of power is due to other causes.
Also, there is a TC speed sensor but I could not find that in OBD-II tool I am using... anyone knows the request address for that beast may be, so I could provide it to the obd-ii to get it. If I compare engine rpms and TC rpms I should get clearer idea on how well TC transfers torque. Or am I wrong?

Can "smth vibrating" be turbine runner together with the tranmission shaft? if I understand correctly, turbine runner and shaft do not rotate during stall test. So they still can be unballanced/loose and do not impact stall test, right? Also just to remind -- I get most of vibration at 20mph -- so it has to be corresponding rpms in turbine/transmission to get it into "resonance". Stop -- don't that rules out TC completely???? TC rotates at engine RPMs. And my vibration is not engine rpm related. DOH -- why I didn't come up with that argument to the "mechanic"... so it boils down again to differential/driveline/supports/etc... if that is differential anyways I am f%%ed even more I guess :-\

Will go read more about TC anyways -- thank you nipper for the link. I remember also reading a while ago "Readers Digest Complete Car Care Manual" which also has quite nice description. Though now I am very hesitant to suspect TC.

As for propeller-shaft -- I really do not see why it should vibrate more torque I provide in FWD mode -- it rotates, yes. But I do not have vibration without torque applied. Vibration doesn't change a bit if I switch to FWD mode when propellershaft does not get torque.

So -- it is not propeller shaft, neither CVs.

#8 nipper

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Posted 06 July 2007 - 04:45 PM

Ok i dont think anyone has asked you to do this

Find a straight stretch of road (downhill) if possible.

Get the car up to vibration speed. Get 5mph over that speed. Put the car in neutral and shut it off. Does the vibration go away? If not:

Tires (out of round, flat spots, broken belts, shifted belts)
Wheels (bent or balance)
Brake Rotors (out of round, hard spots)
Wheel Bearing (s) .. which can be sneaky.

If it does go away, motor mounts.

nipper

#9 grossgary

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Posted 06 July 2007 - 05:01 PM

good job nip. i like the idea of some more testing, drifting, in neutral and accelerating without the engine (down hill) through the vibration range.

that it's mostly speed related would lead me to think that it's driveline related...wheels, tires, bearings, axle in the front. if it were engine or trans related i'd expect more variance than 20-25mph.

#10 nipper

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Posted 06 July 2007 - 05:11 PM

good job nip. i like the idea of some more testing, drifting, in neutral and accelerating without the engine (down hill) through the vibration range.

that it's mostly speed related would lead me to think that it's driveline related...wheels, tires, bearings, axle in the front. if it were engine or trans related i'd expect more variance than 20-25mph.


Also sometimes you have to wait for things to get worse in order to properly diagnose them.


nipper

#11 yarikoptic

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Posted 06 July 2007 - 05:49 PM

Thank you guys for ideas. I will try to do "pass through 20 mph" while going downhill, and other things you said. Though I am pessimistic -- since as I said it occurs only at acceleration (kinda half-throttle) as soon as I drop torque vibration goes away. Also
[quote name='nipper']
Tires (out of round, flat spots, broken belts, shifted belts)
Wheels (bent or balance)
Brake Rotors (out of round, hard spots)
[/qoute]
tires/wheel were rotated twice by now -- that didn't change symptoms. Also the vibration doesn't seem to come from any particular side -- seems more in the middle. Also if it would be in front wheels I would expect hard impact on the stearing wheel -- like when it happens with unballanced tires.
[quote]
Wheel Bearing (s) .. which can be sneaky.
[/quote]
left one was changed after problem appeared. and once again -- vibration would be from one side or another... may be bearing in differential -- that would be more like it...
[quote]
If it does go away, motor mounts.
nipper[/quote]
motor or transmission mounts is the beast I also suspected -- also weak mounts might result in excessive tilt of transmission so may be propeller shaft also gets out of optimum angle or simply starts amplifying vibration.

#12 nipper

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Posted 06 July 2007 - 05:51 PM

motor or transmission mounts is the beast I also suspected -- also weak mounts might result in excessive tilt of transmission so may be propeller shaft also gets out of optimum angle or simply starts amplifying vibration.


Tranny mount.

nipper

#13 bulwnkl

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Posted 06 July 2007 - 05:51 PM

Though I like your logic, I think you cannot rule out the driveshaft(s) from this line of thinking. I've had u-joints cause strange troubles (vibration, grinding, noise) at certain speeds and not others, and either only under power or upon deceleration. They work a little differently than how simply you're making things out to be. That doesn't necessarily mean they are the problem, only that you haven't yet ruled them out, IMO.

#14 montana105

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Posted 06 July 2007 - 07:31 PM

I'm going with Nipper on this,motor mounts

#15 yarikoptic

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Posted 06 July 2007 - 07:31 PM

That doesn't necessarily mean they are the problem, only that you haven't yet ruled them out, IMO.

indeed... to rule it out complete I would need to take the shaft off, and inspect it... actually the best would be replace it or drive without it -- but from another thread where the question was: I am not sure if that is possible to drive with AT's hole (after yoke of shaft being pulled out) patched with smth (and with what? :-)) Did anyone do this?

#16 yarikoptic

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Posted 06 July 2007 - 07:34 PM

I'm going with Nipper on this,motor mounts

btw -- is it doable to replace them without pulling engine out completely (like service manual says to do)? I guess it should be doable... also a friend of mine has a nice lift which he used to support his VW engine while replacing the clutch -- so I can raise the engine a bit I guess... anyone can refer to some online howto? although it sounds like a part swapping I would not mind doing it ... may be I should check the price on them first though :)

#17 nipper

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Posted 06 July 2007 - 07:40 PM

btw -- is it doable to replace them without pulling engine out completely (like service manual says to do)? I guess it should be doable... also a friend of mine has a nice lift which he used to support his VW engine while replacing the clutch -- so I can raise the engine a bit I guess... anyone can refer to some online howto? although it sounds like a part swapping I would not mind doing it ... may be I should check the price on them first though :)


Transmission mount takes most the abuse and can easily be done with the engine in the car.

nipper

#18 yarikoptic

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Posted 06 July 2007 - 07:48 PM

Transmission mount takes most the abuse and can easily be done with the engine in the car.

indeed -- it is relatively at "long arm" so might oscillate quite a bit... I will shop around for it probably (do not have subaru fast unfortunately to list parts for my VIN to get it ordered online)
is there any way to troubleshoot it at least a bit? tranny does move a bit with a hand but...

#19 montana105

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Posted 06 July 2007 - 07:52 PM

but,but,but-no tangent here but have someone rev the engine while pressing the brake while you are looking at things.Rear of engine to tranny shouldn't move much at all,you'll se what i'm talking about if the mount is bad.John

#20 nipper

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Posted 06 July 2007 - 08:02 PM

I had mine replaced last year. I had a very mild vibration in blue, but i thought that was because fo the TB, and a occasional clunk (again TB was blamed). When the dealer rebuilt my AWD, he replaced the tranny mount since he was there, as it was shot, and the tech noticed a vibration in the driveline.

The clunk and vibration were gone.

Food for thought.

You can also test the tranny mount with an equalizier (what is generically known as a BMF pipe or screwdriver) and see if you can pry up on the tranny.

nipper

#21 Kilroy

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Posted 06 July 2007 - 11:28 PM

I had mine replaced last year. I had a very mild vibration in blue, but i thought that was because fo the TB, and a occasional clunk (again TB was blamed). When the dealer rebuilt my AWD, he replaced the tranny mount since he was there, as it was shot, and the tech noticed a vibration in the driveline.

The clunk and vibration were gone.

Food for thought.

You can also test the tranny mount with an equalizier (what is generically known as a BMF pipe or screwdriver) and see if you can pry up on the tranny.

nipper


BMF pipe, LOL!! :D

Interesting thread, I look forward to reading about the results of the downhill coasting test.

#22 yarikoptic

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Posted 07 July 2007 - 04:01 PM

cruising downhill while passing 15-20mph range slowing down or accelerating (due to downhill) in N, as I suspected, didn't even reveal any vibration.
Vibration itself btw does not appear with a light acceleration/torque applied, it comes when accelerating medium hard, or going up-the-hill, especially if 20mph speed is maintained for a while.
Also a bit of more characteristics of vibration, when it vibrates and I rapidly release the torque (release gas pedal) vibration doesn't go immediately go away -- it is possible to feel 2-3 more vibrations before it is gone (gives me more evidence in "tranny support" version)

and btw -- indeed I probably have problems with cat converter -- so I need to unbolt the pipes from the engine block, but I guess I better get replacement gaskets ready first. And test drive it not on a weekend night ;-)

Also I could not find a section on exhaust in 3.0L Subi within Subaru repair manual. What I have is seems to be specific to 2.5L -- I have 1 catalytic converter right before the flanger which connects to the rear (or middle) pipe -- right under ending of AT. Also there is smth in each sleeve (left, right) which look like a possible CC. Also I do not see how first CC I mentioned can be disconnected from the left sleeve -- there is no visible flanger or a connector.
Is there a diagram anywhere? May be someone could send me a picture from subaru fast? :-)

#23 yarikoptic

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Posted 09 July 2007 - 08:10 PM

today (after I "touched" the car in many places) mentioned also that when I brake with engine after a bit of torque my rpms start to wild from 900 to 1600 rpms or so with 1 sec period... I guess I touched vaccum somewhere... time to find a T connector to connect my mityvan to test vacuum in the intake. I just wonder what would be best/easiest place to get T adapter (if I find any) into on my H6?




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