Transmission Jerk On Highway And Foam In Fluid?

[wheelsup]

Did a few transmission drain/refills the latest was a few weeks ago. Checked the fluid level, perfect between max/min at that time. Fluid was a nice color and not burnt.

Driving to work 21 miles each way the car was fine over the last few weeks. No issue except a slightly hard shift from 2nd->3rd. That has been present for the last few months though.

However, driving a 180 mile trip today around 80-100 miles in the car bucked and jerked. It did this once, I didn't think anything of it, I thought we just hit a bump when it was upshifting and it happened to jerk a bit.

Did it again around 10 minutes later.

Then it kept doing it, 2-3 times in a row for about 3-4 minutes and then didn't do anything for 10 minutes or so. I pulled over and checked the fluid, there was some bubbles/foam on the end of it. It wasn't burnt. Nothing leaking. It seemed to happen more when going downhill although it happens on any road condition.

I put some Lucas Stop Slip in it as it feels like it's slipping in 4th gear, slipping by a few hundred RPM's and then "catching" again causing the jerk although I'm not positive that is the case. This however did not help, as it continued to "jerk" and bang every few minutes. I elected to continue and at lower RPM is doesn't seem to be an issue but honestly I can't tell as we only spent a few minutes at lower speed off the highway.

Thoughts? New tranny time? Or something else?

1995 GLT w/ 146k on it

[pio]

Once in awhile mine gets some foam like bubbles on the dipstick, but has never jerked once since I've owned it, however it could be anything in the driveline, the engine missing, something in the tranny, CV joint catching weird, accessory catching weird, waterpump going out..anything that could influence the engine's RPM can cause it to jerk, not just the tranny. I know this helps not at all, but if you look only at the tranny you may miss the real problem when it resurfaces after a rebuild.

The reason I mentioned the waterpump in particular is my old 91 civic auto had the same thing, it would kind of jerk once in awhile then be fine, then jerk a bit some more, couldn't for the life of me figure it out until I went to change the timing belt, the waterpump was actually grinding its impeller? thing on the housing as the bearings had gone bad, allowing it to wiggle around, so when it caught the housing it would kind of stall the timing belt, causing the car to jerk when it happened. So glad the belt held out, damn interferance engines...

[Mete Goktepe]

Hello,

I'm writing this reply because I own the same car you do and I had the same issues the year before I replaced the transmission.(my internal mechanical parts were worn badly so solenoid replacement didnt cure the problem)first do you have the orange arrow blinking while this happens? if you do it might be easier to find out what exactly it is. if not you can do a few things.. drain the fluid and flush the trans.. also there is a transmission fluid treatment called "Motor silk" it might help you.. what happens with most 850's is the control unit under the transmission housing has solenoids in it.. there are a total of 4 solenoids.. these are STH,SL,S1 and S2

STH controls the system pressure but it cant be replaced you will have to replace the whole control unit to have this replaced.

SL controls lock up function

S1 and S2 control shifting functions..

you might try to flush the trans and if there is no improvement replace the S1 and S2 solenoids. this will cure the problem unless the clutches and the bands are responsible for slipping and hard shifting.

the solenoids SL,S1,S2 are replaceable STH is not.

good luck

[troyhyde]

Sounds like it could be a misfire. Check continuity on the plug wires and see if one is measuring weird. Replace plugs if they are older.

The other day my cylinder 3 plug wire went dead. No continuity at all. Similar symptoms until it finally threw a check engine light.

Could be trans. solenoids as well. Hopefully not.

[wheelsup]

Got a CEL on the ride back home. Around 50 miles it started doing the same thing again. CEL came on literally in the last .5 miles. Car was running pretty bad for the last couple miles. Lot's of perceived slippage in 3rd gear.

A1 1-1-1

A2 1-2-1

A3 2-1-1

2-1-3

2-1-4

1-4-2

4-2-4

A7 1-2-2

1-1-3

2-3-1

A1 is tranny I think so good news no codes? A2 is MAF sensor, A3 is ABS not sure why the codes are throwing now, and A7 I have no idea. The up arrow of death light isn't on or blinking. I do suspect the tranny though.

Thoughts?

[wheelsup]

Once in awhile mine gets some foam like bubbles on the dipstick, but has never jerked once since I've owned it, however it could be anything in the driveline, the engine missing, something in the tranny, CV joint catching weird, accessory catching weird, waterpump going out..anything that could influence the engine's RPM can cause it to jerk, not just the tranny. I know this helps not at all, but if you look only at the tranny you may miss the real problem when it resurfaces after a rebuild.

Hi Mete thanks for the response. With getting the same issues I'm am worried it is the tranny. Did you go with a rebuild or a used? I'm thinking used off Ebay for $350 shipped to a place that would put it in for me for around $500. Seems the cheapest way to go but you get what you pay for. I don't want to dump $3k on a rebuilt one into this car. If so I will probably just part it out.

Waterpump was replaced a couple months ago, so that shouldn't be the issue.

[troyhyde]

No misfire codes. Perhaps not the ignition.

Pedal sensor is a fairly common problem and not hard to fix. Doesn't really produce the issue you are having in my experience. All of the ABS sensor issues could be resulting from a ground strap issue. Seems unlikely that they would all fail at the same time. Could relate to the MAF code as well. Could be causing some wacky electronic signals to the transmission ECU which is causing the hunting/slipping.

Make sure you have the proper level of trans. fluid in. Can't think of anything that would introduce bubbles unless you have a loose cooler hose which could be affecting the pressures in the trans.. Seems like you'd see a big leak. Internal transmission problem? You've got your work cut out for you on this one.

[AlvinL]

Got a CEL on the ride back home. Around 50 miles it started doing the same thing again. CEL came on literally in the last .5 miles. Car was running pretty bad for the last couple miles. Lot's of perceived slippage in 3rd gear.

A1 1-1-1

A2 1-2-1

A3 2-1-1

2-1-3

2-1-4

1-4-2

4-2-4

A7 1-2-2

1-1-3

2-3-1

A1 is tranny I think so good news no codes? A2 is MAF sensor, A3 is ABS not sure why the codes are throwing now, and A7 I have no idea. The up arrow of death light isn't on or blinking. I do suspect the tranny though.

Thoughts?

Check the pinned 'DTC Information'.

[Mete Goktepe]

Hello,

the codes:

A7 2-2-2 Temp signal interval too long.. maybe caused by a bad Ect sensor. the other two codes of A7 I couldnt find them in Vadis.

if the tranmission still functioning poorly, like I told you first flush the trans fully and try again. be sure that the fluid level is at or near maximum line in dipstick.in order to be sure that the reading is accurate do the following.

the car should be at operating temperature and idling.. move selector lever from P to L and then back from L to P. wait 3 seconds in each position.and after that leave the lever at P position wait 2 mins and still the car should be idling then measure the fluid level. if it level is near or at minimum mark you have half liters oil missing. correct the level and measure it until its correctly displayed.

Trans Lag Test:

same as above procedure but with one difference the lag between each position should be less than 1.2 seconds.. if the delay is larger I'm afraid system pressure is low and the trans is on its way out. in this case replacing the transmission would be the cheapest way because replacing the control unit may not correct your problem especially if the internal clutches or bands are worn.

[Mete Goktepe]

codes continued:

A3 Brake System: 2-1-1 left front wheel sensor no signal when moving off

2-1-3 left rear wheel sensor no signal when moving off

2-1-4 right rear wheel sensor no signal when moving off

1-4-2 Brake light switch open or short circuit in signal

4-2-4 Tracs pressure sensor faulty or short circuit

A1 Auto Trans: 1-1-1 this means there is no fault in the diagnostic system and system is operating within the factory specs however as I said there might be worn mechanical parts in the trans and soon the orange up arrow light might blink.

A2: 1-2-1 maf sensor signal absent or faulty. this code is very common and mainly the reason is oxidized of chafed maf sensor connectors.. clean the maf connector with an electronic contact cleaner and then plug and unplug it for 20 times. it will solve the problem.

A7: 1-1-3 fuel gauge sensor open or short circuit

2-3-1 no information available at this moment sorry.

for the brake system codes try clearing the codes from the system and check if they will come back. to clear the codes after all codes are displayed for once press the button for 5 seconds and led will light up, then press the button for another five seconds. then press the button once again for 1 seconds.. the display should show 1-1-1 no errors found. drive the car and later check if the codes are back.

good luck

[wheelsup]

Thanks Mete you have been very helpful!

I think I do have a problem with the MAF I noticed today when I started it, after idling for a few moments with it in park the idle dropped a few hundred RPM then popped back up. So that isn't the tranny doing that.

Also I cleared the codes and in 20 miles they haven't come back. I think the ABS was just a fluke. We'll cross our fingers on that one.

I did the time test with switching gears and it's almost instantaneous. Very little lag. Certainly not even close to a second.

I drove it a few miles, put it back up on ramps and drained the fluid again. More bubbles. Not a ton but certainly noticeable. So something in the tranny is causing bubbles to form. I topped it back off with the correct amount of fluid, checked it a few times, it definitely has a full amount of fluid in it. So not enough fluid is out.

Anyone know what else can cause bubbles/foam in the fluid? Because it seems that this is why gets f'ed up around 50-70 miles into the drive, too much foam. I drove it to work today no problems but again it's only 20 miles. This could have been an issue I've been having over the last 6 months after my first drain/refill and I didn't even know about it. So I guess it's true, if you have old fluid DON'T TAKE IT OUT!!

[Mete Goktepe]

for the maf you can go to a salvage yard and get another maf sensor from a wrecked volvo.. it will be the best way to get rid of maf problem. but for the fluid bubbling problem there is definitely something wrong but I have no idea about the cause.. maybe the trans could be overfilled with the fluid get that checked and be sure there is no excess fluid in the trans.

I recommend that you go to a shop who does tranny job and get their idea..

good luck

[wheelsup]

for the maf you can go to a salvage yard and get another maf sensor from a wrecked volvo.. it will be the best way to get rid of maf problem. but for the fluid bubbling problem there is definitely something wrong but I have no idea about the cause.. maybe the trans could be overfilled with the fluid get that checked and be sure there is no excess fluid in the trans.

I recommend that you go to a shop who does tranny job and get their idea..

good luck

I was going to go to a european tranny shop to have them take a look at it. Also I hear the AW50-42le transmission is the same as in Toyota Trucks, possibly the Tundra. Also used in the Daewoo Leganza. There are a lot on ebay w/ low miles. I'm wondering if they are exact bolt ons? Thoughts? Or would there be different sensor inputs?

[crazykn]

If you get another transmission, you have to make sure it has the right connections and sensors.

The 93-95 850 transmissions provide the speedometer signal (for speed) while the 96-98 (98 S70) models get the speedometer information from the ABS and wont' have that sensor for the speed.

Bubbling/foaming of transmission fluid usually indicates to me that the fluid level is low or high (excessively).

[wheelsup]

If you get another transmission, you have to make sure it has the right connections and sensors.

The 93-95 850 transmissions provide the speedometer signal (for speed) while the 96-98 (98 S70) models get the speedometer information from the ABS and wont' have that sensor for the speed.

Bubbling/foaming of transmission fluid usually indicates to me that the fluid level is low or high (excessively).

Thanks crazy, I am going to double triple and quadruple check the level again but I think it's spot on. Next step is a tranny shop I guess.

It would almost be fun to buy a used Daewood AW50-42LE and see if they can be matched up, I found some for $400 with 30k on them.