4L60E problem.
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
4L60E problem.
First of all, automatic transmissions are black boxes to me.
Recently, I noticed that when I manually downshift, i.e. going downhill and wanting to use compression braking of the engine, I noticed that the transmission seems to be "freewheeling". This used to work. I really can't say when it stopped working.
The trans downshifts and upshifts (manually and automatically) without complaint, it operates in OD as smoothly as it ever did. Lockup seems to be working at freeway speeds.
Fluid is full, clear and has no burnt smell. It's been serviced about every 25K miles (note: just passed 150K miles this weekend).
The only symptom is the lack of engine braking in lower gears.
Anyone have any ideas on what to look for or how to diagnose it?
Thanks,
JR
Recently, I noticed that when I manually downshift, i.e. going downhill and wanting to use compression braking of the engine, I noticed that the transmission seems to be "freewheeling". This used to work. I really can't say when it stopped working.
The trans downshifts and upshifts (manually and automatically) without complaint, it operates in OD as smoothly as it ever did. Lockup seems to be working at freeway speeds.
Fluid is full, clear and has no burnt smell. It's been serviced about every 25K miles (note: just passed 150K miles this weekend).
The only symptom is the lack of engine braking in lower gears.
Anyone have any ideas on what to look for or how to diagnose it?
Thanks,
JR
Pro
Joined: Feb 2000
Posts: 717
Likes: 44
Re: 4L60E problem. (John Row)
I have the same year as yours but only 77000 miles and mine does the same thing. It freewheels for about 2 to 5 seconds then connects very smoothly with the lower gear. It has allways done this from the beginning. The trans fluid has been changed every 15000 miles. It appears to be normal operation.
My reply assumes that you are downshifting from "circle D" position to a "D" and not into "L" at speeds above 40 mph.
My reply assumes that you are downshifting from "circle D" position to a "D" and not into "L" at speeds above 40 mph.
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: 4L60E problem. (ETHYL)
It used to immediately downshift and engine compression would immediately begin slowing the car. I would use it to keep from having to continually ride the brakes going downhill. Now, downshifting has no effect at all.
Before, if I put it in 1 or 2 and accellerated then lifted, engine compression would immediately slow (and I would get that neat popping exhaust sound). Now, accellerating in 1 or 2 and lifting the car just coasts at the same speed.
Before, if I put it in 1 or 2 and accellerated then lifted, engine compression would immediately slow (and I would get that neat popping exhaust sound). Now, accellerating in 1 or 2 and lifting the car just coasts at the same speed.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 59
From: Fremont Oh
Re: 4L60E problem. (John Row)
John,
It could be possible that your engine is finally gettng some wear after ~gulps~ 150 thousand miles, the trans could be fine but if you are getting some "blowby" that could keep you from seeing the compression braking you "once knew" .... when you go to the immediate fuel mileage settings on your computer will it go clear to 99 ? That would be a clear tale as to whether it is the trans slipping or the engine just maturing....
just a thought ...
Mo
It could be possible that your engine is finally gettng some wear after ~gulps~ 150 thousand miles, the trans could be fine but if you are getting some "blowby" that could keep you from seeing the compression braking you "once knew" .... when you go to the immediate fuel mileage settings on your computer will it go clear to 99 ? That would be a clear tale as to whether it is the trans slipping or the engine just maturing....
just a thought ...
Mo
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: 4L60E problem. (Mo_Bandy)
No oil consumption, no smoke, clear spark plugs.
I doubt that I would have lost all compression in the last 10K miles. This was kind of a sudden thing. And it's a definite "freewheel" feeling. Foot off the gas going downhill in 2 we were doing 40+mph and accelerating.
At 150K, it's just broken in. :D
I doubt that I would have lost all compression in the last 10K miles. This was kind of a sudden thing. And it's a definite "freewheel" feeling. Foot off the gas going downhill in 2 we were doing 40+mph and accelerating.
At 150K, it's just broken in. :D
Le Mans Master
Joined: Apr 2000
Posts: 6,294
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From: Amateur driver on open course.
Re: 4L60E problem. (John Row)
They are black boxes to me also. Mine downshifts fine when I manually do it. I can offer this, and I can't stress it enough...the 4L60E's are extremely sensitive to fluid level. Either too low. or too full.
Drifting
Joined: Jun 2001
Posts: 1,997
Likes: 1
From: Lake Ozark MO
Re: 4L60E problem. (John Row)
This is the only related thing I could find in my Helms manual... note the "Manual Downshift" section... hope it helps. I'm "slush box" stupid.
[Modified by Dan Parker '96, 7:18 PM 10/15/2002]
[Modified by Dan Parker '96, 7:18 PM 10/15/2002]
Pro
Joined: Sep 2001
Posts: 743
Likes: 4
From: Guyton GA
Re: 4L60E problem. (John Row)
There is a gear mechanism in the trans that only rotates in one direction(I forget what it is called). The one way gear is probably not engaging. It would require a trans disassembly. I can email you more info if you want.
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Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: 4L60E problem. (ETHYL)
Manual definitely says it should use engine braking when you manually downshift.
After learning way more than I ever wanted to know about the 4L60E, it appears that I have a problem with the OVERRUN CLUTCH. I looks like a trip to the tranny shop goes into the budget.
After learning way more than I ever wanted to know about the 4L60E, it appears that I have a problem with the OVERRUN CLUTCH. I looks like a trip to the tranny shop goes into the budget.
