bad torque converter symptoms

[wyatt_earb]

I really dont believe the transmission is burned up, it shift fine, doesnt slip out of gear, or make any noise. But the blazer does lack power, I know its a 2.8, but its still a dog. Also while driving at a consisitent speed if I tap the break the rpms dont go up, like they do in my 87 2.8 s10 truck. Guess I'm going to have to look at this. Anthing I should look for while driving or while working on it?

[MT-2500]

Originally Posted by wyatt_earb

But why would it be burnt up at 85,000 miles, this is an old city vehcle and they're good about general maintance on their vehicles. I was thinking about flushing the rest of the fluid out and seeing what happens. Although I've read on the internet that you should never flush a transmission with burnt fluid b/c it'll cause the transmission to go out. Tomorrow I'll check the fluid for "particles" in it, possibly being chunks of seals etc...

Also when I had it looked at a year ago, for the whole shuttering thing, the guy said something was going out with the torque converter. Said to unplug the wire going to the transmission if the lucas didnt make it go away. If I remember correctly he said it had something to do with it going into overdrive, and electric torque converter maybe, I cant really recall. I'm going to stop by the local transmission shop and talk to them, I believe they look at it for free....

About the tune up, I've already done that, along with a long long list of other things. The gas problem wont go away, which is why I'm thinking this tranny problem has something to do with it. Like I said, while going 65ish sometimes it just shoots the rpms up and it struggles to go 55-60.

From what you described in this post and have told us so far.
Your transmission is on it's last leg.
Burning fluid and dropping out of gear is not good and points to internal transmission problems.
A lot more than a bad converter.
A new filter and another bottle of Lucas may put a band aid on it for a while.
But if you you are going to keep the truck it is another transmission or rebuild time.
Good Luck MT

[wyatt_earb]

Took it to a tranny place that does free diagnosis, he said its definetly the TCC. Said it could be the break switch or the solenoid, and if neither of those then its not worth fixing. Was told if I get the TCC to start kicking in, then to take the transmission pan off and jack up the blazer as high as possible to allow most of the fluid to drain out. Said while the fluid was burned up it has low miles on it and he didnt feel any "grit" in it. This sound right to anyone? And I've never messed with a brake switch, said I might just be able to clean it off....

[J-Mech]

If you have a shutter, or think maybe it is slipping it probably is. If it is an old sity truck it has done a lot of start and stop driving which would be espically hard on the converter. Torque converters do not necessarily take the trans out with it. I have replaced many converters and not the trans. The reason for not changing the fluid, because it can make it fail is true. There are additives in tranny fluid that clean. Worn fluid lacks the additives (these are what depletes in all oils and the reason for changes) so it cleans that dirty old tranny too fast causing the clutches to fall apart and fail. Replacing the torque converter is reletively easy and inexpensive. You should just bite the bullet and do it.

[wyatt_earb]

This is why I took it in and had it looked at, he drove it around and had a computer hooked up. Said the converter wasnt the problem it was the TCC kicking in and out, when it was going out, and not its completely not locking in causing the fluid to get burned up.

[MT-2500]

Originally Posted by wyatt_earb

This is why I took it in and had it looked at, he drove it around and had a computer hooked up. Said the converter wasnt the problem it was the TCC kicking in and out, when it was going out, and not its completely not locking in causing the fluid to get burned up.

Is it still dropping out of OD down to 3 gear?
Is the TV cable adjusted good?

Are you using silicone or sealant on the oil pan gasket?

It would be rare for a converter to burn fluid.

On a normal take off at what MPH does it upshift?

[wyatt_earb]

Maybe I didnt understand what he was saying, but he said when you apply the break a valve is suppose to open in the tranny, allowing it to cool down. He said this is the problem and to check the break switch, which he said even if the lights are working it still might not be functioning correctly. And he said if i still couldnt feel it locking in then it was most likely the solenoid. From what I understood the TCC locks in not matter what gear you have it in, and when its not working, like on mine, then the motor will run at 500-1000 rpms hire. So it goes into OD and all gears fine, but once your cruising at a consistent speed the TCC is suppose to lock in. You can test this by driving down the road around 55mph and lightly touch the break. If the TCC is working properly the motor should rev up, but this doesnt happen on mine b/c its always reved up. I hope I made that as clear as mud...... I'll do my best to answer any other question. THANKS FOR ALL THE ADVICE SO FAR!!!

[MT-2500]

Originally Posted by MT-2500

Is it still dropping out of OD down to 3 gear?
Is the TV cable adjusted good?

Are you using silicone or sealant on the oil pan gasket?

It would be rare for a converter to burn fluid.

On a normal take off at what MPH does it upshift?

Answer these questions for more help with it. .

It sounds like you need to find another trasmission man.
I never heard of one working quite like that.

[wyatt_earb]

I used rtv gasket on the pan when I changed the filter. It never dropped out of OD. I'm not sure what the TV cable is.... And I'll have to take it out and watch the mph while its shifting, to be honest it seems to run and shift fine. Never shifts hard or slips, but it'll go up in rpms while driving 65+ for and extended distance and it acts like its not all the way in gear. But itll ride at 55mph fine. I'm going to try the break switch out this weekend and if that doesnt work then I'll try out the solenoid. Hope this helps...

[MT-2500]

Originally Posted by wyatt_earb

I used rtv gasket on the pan when I changed the filter. It never dropped out of OD. I'm not sure what the TV cable is.... And I'll have to take it out and watch the mph while its shifting, to be honest it seems to run and shift fine. Never shifts hard or slips, but it'll go up in rpms while driving 65+ for and extended distance and it acts like its not all the way in gear. But itll ride at 55mph fine. I'm going to try the break switch out this weekend and if that doesnt work then I'll try out the solenoid. Hope this helps...

Rule no 1
Do not use RTV gasket sealer on the 700R4 pan gasket.
That may be some of your problem.
The sealer plugs the OD band servo release drain hole.
And can burn up band and trans fluid and transmission.

[berniescout]

what should you use?? just a dry gasket?? another sealer?? or just wipe it w dexron III. i am about to do mine for the first time and am using mobil 1 atf any thoughts??

[MT-2500]

Originally Posted by berniescout

what should you use?? just a dry gasket?? another sealer?? or just wipe it w dexron III. i am about to do mine for the first time and am using mobil 1 atf any thoughts??

No Moible 1 .
No dope or additive.
No flushes.
No sealer or greese or fluid on pan gasket.
Just clean dry cork pan gasket and new filter and what the book calls for on transmission fluid type.

[wyatt_earb]

Ok. I just changed the filter and I'm going to have to take the pan off again so I'll buy a gasket for it. Is the best way to drain the fluid to jack up the vehicle as high as posslible and let it set over night? This is what I was told, told this will drain most of the tranny fluid.

[blazes9395]

The 2.8 700R4,s are notorious for being poorly performing trannies. If the tranny is not locking up and you drive it like that especially at higher speeds, for a long time, you will overheat it, and eventually damage it. Shuddering is a common tell tale sign of a overheated(ing) convertor. Probably also is a reason why your getting burnt fluid. This does not only mean its your convertor, you could have other tranny problems too.

No SES codes will come up on this tranny, as it is way to old. But if you have a bad VSS, TPS, coolant, especially coolant sensor, as sometimes you don't get a SES light for a boarderline bad coolant sesnor in these old trucks, it will not allow the tranny to lock up. Its designed like this as it allows the engine/transmission to warm up when its cold, but if it has a bad/no, or common cold reading, the ECM will not allow lock-up by default. If any of these sensors don't work, it will not lock up either.

Also to check to see if in fact your TCC is working, there is a TCC ground pin in the diagnostic link under the dash. I don't remember which pin it is, but if you ground it it will force lock-up. Do this when you going about 40mph, ground it at this point, if the RPMs go down and it locks up, you TCC is working. If there is no lock-up when you ground the pin, you have a tranny, or convertor problem.

Good Luck!

[wyatt_earb]

I know the TCC isnt working, b.c it doesnt lock in. I believe you can tell this by lightly applying the breaks, when going a consistent speed, and the rpms dont go up. Plus I was told by the tranny guy that this is why I'm getting bad gas mileage. Also I have replaced the coolant temp sensor on the intake, infront of the TBI, but not the one by the manifold.