98 Blazer 4L60E Trans Problems

Ive got a 98 Blzer LS 4.3L V6 with the 4L60E trans.
Problems originated with occasioanally slipping out of overdrive after getting warm.Trans would continute to operate, just at a higher RPM.

Just as maintenance and to rule it out as a culprit, I dropped the tranny fluid pan and replaced the filter/screen and refilled the trans with fluid.

Now I am trouble with starting out.If I put it in drive, I need at least 1500RPM to get the truck moving, and its slow to start.At about 15 MPH it seems to 'catch' and I can go.

If I put it all the way down into 1st, it seems to help but does not solve the problem.Once again though after about 15MPH I can throw it into drive and it will shift out fine from there.

I have checked and double checked fluids to make sure and everything is fine there.

Ive read possibly 100 webpages with info on the trans and common problems and talked to several mechanics and heard about 20 different ideas about what may be causing it.

If anyone would care to contribute to the list of possibilities or if youve had a similar experience and care to explain your solution(to either problem) I would greatly appreciate it.

Ive got a 98 Blzer LS 4.3L V6 with the 4L60E trans.
Problems originated with occasioanally slipping out of overdrive after getting warm.Trans would continute to operate, just at a higher RPM.

Just as maintenance and to rule it out as a culprit, I dropped the tranny fluid pan and replaced the filter/screen and refilled the trans with fluid.

Now I am trouble with starting out.If I put it in drive, I need at least 1500RPM to get the truck moving, and its slow to start.At about 15 MPH it seems to 'catch' and I can go.

If I put it all the way down into 1st, it seems to help but does not solve the problem.Once again though after about 15MPH I can throw it into drive and it will shift out fine from there.

I have checked and double checked fluids to make sure and everything is fine there.

Ive read possibly 100 webpages with info on the trans and common problems and talked to several mechanics and heard about 20 different ideas about what may be causing it.

If anyone would care to contribute to the list of possibilities or if youve had a similar experience and care to explain your solution(to either problem) I would greatly appreciate it.

What all was in bottom of pan and in old filter?
Was fluid burnt?
Are you checking fluid level hot in park engine running?
I would try another qt. or two of fluid and see if it makes any difference.

Did you get the right filter and pick up tube seal in it?
There are two or 3 different pan setupd on them.

Any check engine lights?

To check a transmission out it needs to be put on a transmission capable scannner and watch for slippage and check for codes and read out transmission data.
Post back code no.

What all was in bottom of pan and in old filter?
Was fluid burnt?
Are you checking fluid level hot in park engine running?
I would try another qt. or two of fluid and see if it makes any difference.

Did you get the right filter and pick up tube seal in it?
There are two or 3 different pan setupd on them.

Any check engine lights?

To check a transmission out it needs to be put on a transmission capable scannner and watch for slippage and check for codes and read out transmission data.
Post back code no.

Thanks for the reply.
Pan was rather clean and the fluid didnt really seem burnt.
I am checking the fluid at operating temp, level gound, in park.Im concerned about adding much more fluid as it already seems to be pushing overfull.
I have the deep/flat bottom pan and the new filter looked just as the old on did.Im not sure about a seal.I did get a small cylindrical piece of plastic in the new box but it didnt seem to fit anywhere and when I pulled the old on off it dint have anything similar to the cylindrical piece. I didnt match both filters up before installing and they are 100% match down to which pieces are plastic and which are metal.
No check engine lights are currently on other than ABS which I know has a problem because I pulled the fuse out when I first got the truck.(dislike ABS)
I was considering taking it to a local Advanced Auto and having them plug into it and check for any codes which might help but dont want to make things worse by driving it about 40 miles round trip.

Thanks for any help

Thanks for the reply.
Pan was rather clean and the fluid didnt really seem burnt.
I am checking the fluid at operating temp, level gound, in park.Im concerned about adding much more fluid as it already seems to be pushing overfull.
I have the deep/flat bottom pan and the new filter looked just as the old on did.Im not sure about a seal.I did get a small cylindrical piece of plastic in the new box but it didnt seem to fit anywhere and when I pulled the old on off it dint have anything similar to the cylindrical piece. I didnt match both filters up before installing and they are 100% match down to which pieces are plastic and which are metal.
No check engine lights are currently on other than ABS which I know has a problem because I pulled the fuse out when I first got the truck.(dislike ABS)
I was considering taking it to a local Advanced Auto and having them plug into it and check for any codes which might help but dont want to make things worse by driving it about 40 miles round trip.

Thanks for any help
OBD 11 scanner check will not read out transmission problems good.
Needs to be checked out on a transmission/engine capable scanner.

Thanks for the info-Ill see if I can find one locally.

Would it be safe to drive it to the scanner if need be?

In the meantime perhaps someone else would care to take a stab at guessing or possibly even knowin from experience what the problem might be.

Need some proper testing.
Guessing at it or tryiing to fit it to someone elses problem will only cause throwing parts at it.
A good engine/transmission capable scanner is only way to go on checking them out.
If changing filter made it worse better check out the filter.
Something sound wrong there.
Good Luck

Yes common sense would say I screwed up the filter, but I just cant imagine what.All I did was drop the pan swap filters and clean the pan and it went right back on.

Changing filter can also move around wiring and sensor plugins.
Get it on a good transmission/engine capable scanner andf see what shows up.
Post back any codes you find.

Just had the Blazer put on a scanner which read out the following
"P1870 - Transmission Component Slipping"

Hopefully that will help anyone willing to help me.

Just as a side note, it seems to me almost as if the trans will not go into first gear.If I put the shifter into "2" it will never shift, but as soon as I move it to "3" it will shift.Its just getting to about 15MPH which is about when second should kick in that is the problem.Thus my thinking my problem is with my 1st gear somewhere.Just why....unless the code sheds light elsewhere.

Just had the Blazer put on a scanner which read out the following
"P1870 - Transmission Component Slipping"

Hopefully that will help anyone willing to help me.

Just as a side note, it seems to me almost as if the trans will not go into first gear.If I put the shifter into "2" it will never shift, but as soon as I move it to "3" it will shift.Its just getting to about 15MPH which is about when second should kick in that is the problem.Thus my thinking my problem is with my 1st gear somewhere.Just why....unless the code sheds light elsewhere.
That code only says it is slipping.

If you use a good transmission/engine capable scanner it will tell you what gear it is slipping in and how much and shift times.
Without a good scanner just code 1870 is as much use as tits on a boar hog.

Code 1870 usually goes to internal transmission pressure leakage.
Internal parts bad.

Any info on where I might be able to get it on one of those scanners?Im a little untrustworthy of local mom & pop shops but dont want to get hit with more than I need.

Connect a pressure gauge to the line fitting on the LH side of the trans:

http://www.wwdsltd.com/files/4L60EPressureTestPort.jpg

Start and run the engine until the trans is warm. Make sure there is at least 55 PSI in DRIVE, 65 PSI in reverse, and at least 140 PSI in manual 1 or 2 ranges.

As MT suggests, you can use a Tech1 scan tool to read error codes, monitor line pressure with the internal pressure sensor, and control line pressure with the PWM pressure control solenoid right from the Tech1 keypad.

If line pressure cannot be controlled above 50 PSI on a hot trans, something is either mechanically failed or the pressure control solenoid is dead (which should set a DTC). Likely suspects are main shaft seals, pump body and/or slider wear, a check ball blown through the separator plate, and various other possibilities.

As for driving it in this condition, if the line pressure is too low, apply pressure on clutch stacks will be inadequate and the clutches will suffer damage from slippage. On the other hand, there is a fair chance that this has already occurred, and anything you do at this point to remedy the problem is going to involve new clutch discs and steels anyway, so it's your call.