Maybe the VSS?

[SHOfun 93]

Okay this is the newest episode of "as the tranny burns". Lately when I am at highway speeds, I set the cruise control, and approximately 10 minutes later or so the car starts to lose overdrive, and then sometimes buck its way all the way down to 2nd gear. (scary) I always start to slow down when I sense it, so I don't have to worry about engine damage, and I often just click it into neutral to help the tranny refind itself. After I pull to the side of the road, shut the car off, and then restart the car, I then take off again and the tranny will shift fine! I have checked the tranny fluid, and it has a SLIGHT burned smell, but has a nice red appearance, and looks okay. Also, my radiator is in dire need of replacement so the tranny cooler is right against it and with the radiator in essence making more hot air, will the tranny cooler suffer in its ability to keep the fluid cool as well? Some input is needed. Thanks.

 

[luigisho]

Well bucking at highway speeds is a sign of vss failure. Then again, with your tranny history anything goes. wink How long since it was replaced? I would assume a new one was put in during one of the tranny work sessions. At least it's something you can do yourself.

 

[SHOfun 93]

Well I looked on the receipts for the tranny work, and didn't see any mention of it. But like I said, it bucks, I stop the car, restart it, and then itis almost like it resets itself to stay in gear again. Might be the original one. I have been back 3 times for rebuilds to the same shop, so I doubt they are gonna do me any favors. Although the temp problem doesn't seem NEAR as bad, and the fluid integrity of the tranny case hasn't been comprimised like when the tranny went out the other times.

 

[naval-avi8or]

The tranny will throw codes to the PCM. Have you pulled the codes. 600 series codes all relate to the tranny.

<small>[ August 21, 2002, 09:58 AM: Message edited by: naval-avi8or ]</small>

 

[SHOfun 93]

Well when I pulled the codes a while back when I was having problems with the DPFE sensor, I had some 637s come up then, but no CE light since then. Will the VSS ALWAYS send one? I know some codes will go into memory without triggering the CE light.

 

[luigisho]

When the vss went on my MTX it didn't throw any codes. Just the surging on the highway symptom.

 

[poissonverte]

The VSS code is a 452, and my car threw one at me.. and yes I have the same symptoms on the highway when the cruise control is on.. it should also be doing it when you are getting on the off ramps and slowing down and when in traffic.. Odd thing for me it only did it after the car was heated up sufficiently, before that it was fine..

 

[SHOfun 93]

Yep that is when it happens to me too...that is why I suspected that the tranny was going out a few weeks ago, only to find out that after the car sat a while, it was perfectly fine! I have dropped my fair share of trannys and know that if the darn thing is gonna go, it isn't going to heal itself and be okay the next morning. I'll pull the codes this morning and see what I find..

<small>[ August 21, 2002, 10:47 AM: Message edited by: Jeremy Hohn ]</small>

 

[ShoGuy93]

Hey John I hope itisn't anything to bad for u!! My sho went into the shop to day to get the tranny looked at. So i am hoping for the best!! Good luck man!! frown

 

[SHOfun 93]

Brad...just a quick question....

WHO THE **** IS JOHN????

 

[SHOfun 93]

Okay will any of these codes mean the VSS is shot? Pulled them and this is what I found.

522 (O) Park/Neutral Position (PNP) or Clutch Pedal Position (CPP) circuit fault - PNP
Transmission MLP sensor out of range in park - Transmissions

634 (O,M) Park/Neutral Position (PNP) or Clutch Pedal Position (CPP) circuit fault
Electronic shift transmission - Manual Lever Position (MLP) sensor out of range in PARK

I looked for a specific code for a VSS failure and couldn't find one. HELP! It just did it again! shoot

 

[Bluto]

I am very new to the SHO forum.
I am going through the exact same tranny trouble now. I tried to change the VSS without removing the exhaust, and I failed.

Its my belief that the VSS is so close to the block, and exhaust that when it heats up it acts odd.

When my car is running cool the tranny is fine. When I get feeling a bit saucy and heat it up the tranny acts as if it slipping.

I am having the tranny pulled and rebiult with a calibration-lubrication kit, and will have the new VSS installed then. I ain't fartin around with a tranny that has 125000 on it.

Do you guys think some asbestos between the VSS and the VSS heat shield will help reduce heat to that sensor?

-Bluto

 

[luigisho]

Jeremy, I'm not sure how the mlp sensor affects driveability but I know someone who does. His rebuilds are the best around and each one comes with a new VSS and MLP. So call up D.L. and see what he says. I hardly ever see that code around. Maybe the tranny sensors are malfunctioning and doing neutral drops on the highway.

Bluto, I see where you're coming from with the heat issue. I wouldn't recommend putting asbestos anywhere someone will be hunting around with their hands someday to change the next time. I'm just funny about stuff like that. People get these things changed without dropping the tranny it's just a real PITA. Oh and since Doug's rebuilds come with new VSS and MLP maybe you should consider replacing the MLP if you rebuild too. One less thing to muck with later.

<small>[ August 21, 2002, 02:56 PM: Message edited by: luigisho ]</small>

 

[DJ SHO]

VSS....What a bastard sensor that thing is. Been there done that. Yes heat starts making a differnce when the sensor is "starting to go bad". It's very very sensitive to change. They y-pipe in the ATX should come out when changing the VSS. We took it out because it was still hot and burning of the arms was getting annoying. So, out it came and acutally made for just enough room to get your arm up in there to get the bolt out.

When it's replaced you'll notice the car just comes back to life. Shifting will be good, steering back to where it should be, and the engine should be more responsive and feel like it's supposed to. My sensor had a slow death and I thought it was just my car getting slower and running doggier because of mileage. Actually it was the VSS the whole time. It was like night and day after I replaced mine. Good luck.

 

[twr]

I maybe wrong, but doesn't the VSS also drive the cruise control, that is so the car knows how fast the it's going. I know this is true on the MTX cars, just not sure on the ATX cars. If you have working cruise, then the VSS should be good.

<small>[ August 21, 2002, 04:19 PM: Message edited by: twrsho ]</small>

 

[SHOfun 93]

The symptoms first started with the cruise control on at highway speeds. Plus when I put mine on, I don't get a cruise control light on in the dash anymore.

 

[poissonverte]

DJ you mentioned steering... seems my steering after getting off the highway is still under VAPS control.. ie. really hard to turn until i wait a few minutes then its back to normal under slow speeds.. man sounds like that sensor is just a bithc to have

 

[SHOfun 93]

Funny...ocasionally when backing in or coming to a stop the steering got stiff...didn't think anything of it, but now that you mention it...the tranny is probably on its originaly VSS since I don't see it anywhere on my tranny repair receipts...well I guess I will tackle that in the near future, probably when I replace the plugs, wires with the intake off...

 

[Mike Kopstain]

luigisho:
When the vss went on my MTX it didn't throw any codes. Just the surging on the highway symptom.

How? Unless you had the cruise on it won't affect driveablility in an MTX.

 

[luigisho]

I thought that was one of the symptoms of a failing vss. I could be wrong. I know it factors into the eec idle program and I haven't looked into it in a while. I haven't had cruise since I bought the thing. I think the previous owner yanked something out. I never use cruise so I haven't really investigated getting it to work again.