4L60E slow to get moving
Thread Starter
Teching In
Joined: Aug 2013
Posts: 14
Likes: 0
4L60E slow to get moving Got an original 4L60E in our work Astro which has been acting up for a while.
In drive, it feels like it starts out in second then drops back down to first when its moving (also when manually selecting first, but not second). Sometimes it's also slow to engage from a stop in either forward or reverse. Once its moving it runs fine. Fluid level is high on the dip stick with some bubbles.
I changed the fluid and filter some time ago. Can't remember if this started happening before or after. Is it maybe overfilled or do I likely have something else going on with it? No codes came up when I scanned it, not sure where to start troubleshooting.
Thanks.
In drive, it feels like it starts out in second then drops back down to first when its moving (also when manually selecting first, but not second). Sometimes it's also slow to engage from a stop in either forward or reverse. Once its moving it runs fine. Fluid level is high on the dip stick with some bubbles.
I changed the fluid and filter some time ago. Can't remember if this started happening before or after. Is it maybe overfilled or do I likely have something else going on with it? No codes came up when I scanned it, not sure where to start troubleshooting.
Thanks.
TECH Junkie
Joined: May 2012
Posts: 3,052
Likes: 716
From: Poplarville, MS
Over filling is almost as bad as under filling. When over filling a trans the fluid level will get up into the spinning parts and get aerated. Aerated trans fluid will compress and not hold the clutch packs tight enough and could cause them to slip.
You did not state how old this trans is. If it is an old unit, it could be that the seals have gotten hard from years of use.
You did not state how old this trans is. If it is an old unit, it could be that the seals have gotten hard from years of use.
Thread Starter
Teching In
Joined: Aug 2013
Posts: 14
Likes: 0
Original transmission, never been rebuilt, 2001 Astro. 187k miles. Been acting up the last 5k miles or so. Doesn’t get driven much lately so it’s been doing this a couple years. We have always kept up with the fluid changes.
I might try draining and measuring the fluid to see if I’ve overfilled it.
I might try draining and measuring the fluid to see if I’ve overfilled it.
TECH Junkie
Joined: Dec 2012
Posts: 3,622
Likes: 1,337
From: Iowa
likely a low AFL pressure issue
with throttle input/pump pressure the afl will come up enough to finally stroke the 1-2 shift valve against spring pressure and give you 1st gear
couple ways to remedy this but a pressure test and computer scan with live data would be better starting points before getting the wrenches out
with throttle input/pump pressure the afl will come up enough to finally stroke the 1-2 shift valve against spring pressure and give you 1st gear
couple ways to remedy this but a pressure test and computer scan with live data would be better starting points before getting the wrenches out
Thread Starter
Teching In
Joined: Aug 2013
Posts: 14
Likes: 0
I will have to get a pressure tester on it. Since I posted the van has a few thousand more miles on it. I’ve noticed it feels like it’s slipping a little under heavy load and on the highway - not sure if it’s the clutches or the torque converter locking/unlocking. It stalled at a stoplight yesterday (once only).
TECH Junkie
Joined: Dec 2012
Posts: 3,622
Likes: 1,337
From: Iowa
you're decision to put this off has likely caused more damage.
I'd just start preparing/budgeting for a rebuild.
You may get lucky but that's the expected result once you get to the point of symptoms you're describing
I'd just start preparing/budgeting for a rebuild.
You may get lucky but that's the expected result once you get to the point of symptoms you're describing
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'
Brett Foote
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Thread Starter
Teching In
Joined: Aug 2013
Posts: 14
Likes: 0
Sorry to resurrect an old thread, but I wanted to close this out for anyone having similar issues.
We have been driving the vehicle the way it was. It’s just a second car that doesn’t get many miles. The symptoms we had include sluggish starting in second from a stop before bucking down into first to speed away, and intermittent bucking at low load in high gear, presumably the TC locking/unlocking. The transmission didn’t slip otherwise. The transmission dipstick had bubbly fluid well above the fill line.
Yesterday we finally found some time to work on it. We dropped the pan and the filter fell right out. Fluid was dark, but not burnt. Some light particulates but nothing large or abnormal. Replaced the filter and filled it up with 5 quarts of the correct fluid, per owners manual.
It drives like a dream now. Starts in first and has power to the wheels. No more bucking in fourth, and no dragging shifts.
I was afraid I had bad internal seals and needed a complete rebuild due to low line pressure or a bad pump, but that appears not to be the case. Either the filter had slightly fallen into the pan, which was pulling air around the filter tube seal, or it was overfilled causing the fluid to foam up. Maybe a combination of both.
If you’re having similar issues, it doesn’t hurt to replace the filter and fluid. Only cost about 50 bucks.
We have been driving the vehicle the way it was. It’s just a second car that doesn’t get many miles. The symptoms we had include sluggish starting in second from a stop before bucking down into first to speed away, and intermittent bucking at low load in high gear, presumably the TC locking/unlocking. The transmission didn’t slip otherwise. The transmission dipstick had bubbly fluid well above the fill line.
Yesterday we finally found some time to work on it. We dropped the pan and the filter fell right out. Fluid was dark, but not burnt. Some light particulates but nothing large or abnormal. Replaced the filter and filled it up with 5 quarts of the correct fluid, per owners manual.
It drives like a dream now. Starts in first and has power to the wheels. No more bucking in fourth, and no dragging shifts.
I was afraid I had bad internal seals and needed a complete rebuild due to low line pressure or a bad pump, but that appears not to be the case. Either the filter had slightly fallen into the pan, which was pulling air around the filter tube seal, or it was overfilled causing the fluid to foam up. Maybe a combination of both.
If you’re having similar issues, it doesn’t hurt to replace the filter and fluid. Only cost about 50 bucks.