Automatic Transmission 2-Speed thru 10-Speed GM Autos | Converters | Shift Kits
Sponsored by:
Sponsored by:

4l80e reverse question

Thread Tools
 
Search this Thread
 
Old Sep 11, 2011 | 08:21 AM
  #1  
cabel1's Avatar
Thread Starter
11 Second Club
iTrader: (3)
 
Joined: Sep 2007
Posts: 233
Likes: 0
From: Wisconsin
Default 4l80e reverse question

I have had my 4l80e in my car now for probably 1000 miles and a couple dozen track passes. Didn't get run to hard brcause I'm having a problem with a nos solenoid. Anyhow the trans was a used gm srta I took it apart and it all lookled good but the direct clutches were discolored. I replaced the direct clutches and added Jakes valve body kit to dual feed the directs. First time driving the car reverse slipped bad getting out of my garage but then was fine? Now as of yesterday it has no reverse. All other gears seem ok. You can tell it goes in but slips One time it shuddered and then backed up but the next thing nothing. Possibly the reverse servo? Just looking for ideas before I pull it apart.
Thanks
Reply
Old Sep 11, 2011 | 10:49 AM
  #2  
Gilbert@Ace Racing's Avatar
FormerVendor
 
Joined: Oct 2006
Posts: 3,123
Likes: 3
From: D-F/W
Default

It is highly possible that the Direct clutches are compromised once again which would imply a chronic issue with that unit being as it was showing stress when you were in it last time. The Overdrive Sprag could be slipping and of course the Low/Reverse band could be inoperative or worn out.

I would suggest removing the pan for an inspection, see what sort of debris is laying there? Then remove the L/R band servo cover, remove the servo and inspect it.

Get that far and let us know what you find. I don't think I would remove it and disassemble it just yet...

One thing you might consider is to put a gauge on it and see if there is a rise or fall in line pressure when you engage reverse. You should see appx 65 psi in park and then somewhere around 120 psi in reverse.

g
Reply
Old Sep 11, 2011 | 01:09 PM
  #3  
slow67's Avatar
Gingervitis Addict
15 Year Member
iTrader: (2)
 
Joined: Nov 2004
Posts: 2,399
Likes: 3
From: DFW
Default

I'd bet you tore a seal on the center support.
Reply
Old Sep 11, 2011 | 02:57 PM
  #4  
cabel1's Avatar
Thread Starter
11 Second Club
iTrader: (3)
 
Joined: Sep 2007
Posts: 233
Likes: 0
From: Wisconsin
Default

Originally Posted by slow67
I'd bet you tore a seal on the center support.
I removed the second seal on the center support when I did it.
Reply
Old Sep 11, 2011 | 09:37 PM
  #5  
Jake's Performance's Avatar
FormerVendor
iTrader: (2)
 
Joined: Oct 2010
Posts: 1,774
Likes: 24
Default

Sounds like a band issue to me. Check the servo clearance when you have it apart, remove the accumulator pistons, both springs from the low servo, and push the pin, washer, and piston against the low band and see how far it goes into the case. I bet it goes in quite a ways.

If you are making good pressure and using my valve body setup, I doubt you've hurt the directs and if so, you would at least feel a difference in the 2-3 shift.
Reply
Old Sep 21, 2011 | 05:58 AM
  #6  
cabel1's Avatar
Thread Starter
11 Second Club
iTrader: (3)
 
Joined: Sep 2007
Posts: 233
Likes: 0
From: Wisconsin
Default

Well I checked the rear servo pin length with the GM tool and the pin was .200"short. I ordered the longest pin from GM which is what the tool said I need. Hopefully that works. Will update when installed.
Reply
Old Sep 21, 2011 | 12:00 PM
  #7  
slow67's Avatar
Gingervitis Addict
15 Year Member
iTrader: (2)
 
Joined: Nov 2004
Posts: 2,399
Likes: 3
From: DFW
Default

Originally Posted by Jake's Performance
Sounds like a band issue to me. Check the servo clearance when you have it apart, remove the accumulator pistons, both springs from the low servo, and push the pin, washer, and piston against the low band and see how far it goes into the case. I bet it goes in quite a ways.

If you are making good pressure and using my valve body setup, I doubt you've hurt the directs and if so, you would at least feel a difference in the 2-3 shift.

Haha yeah I missed where he said all other gears are good.
Reply
Old Sep 23, 2011 | 05:59 AM
  #8  
cabel1's Avatar
Thread Starter
11 Second Club
iTrader: (3)
 
Joined: Sep 2007
Posts: 233
Likes: 0
From: Wisconsin
Default

Update: New reverse/low servo pin installed. I have reverse again And it is firmer than ever
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-1

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-2

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-3

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-4

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-5

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-6

10 Camaros You Should Never Buy

 
story-7

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
story-8

Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

 Brett Foote
story-9

10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

 Verdad Gallardo




All times are GMT -5. The time now is 02:08 PM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE