Express, Savana & G-Series Vans Offered in both a full size van, or a large box truck, the Express is the modern GM workhorse.

Chevrolet Express
Platform: GMT Van

G 20 1981 automatic transmission fluid

Old Jul 11, 2021 | 7:48 PM
  #1  
dtorres's Avatar
Thread Starter
CF Beginner
 
Joined: Feb 2021
Posts: 12
Likes: 0
Default G 20 1981 automatic transmission fluid

Hello,

I've a 1981 G20 van and I need to replace the automatic transmission fluid, could somebody detail the amount of litters or gallons that will require and the most important thing the type of fluid that requires.

thanks in advance.
Reply
Old Jul 12, 2021 | 2:42 AM
  #2  
mountainmanjoe's Avatar
Super Moderator
 
Joined: Feb 2017
Posts: 6,207
Likes: 689
Default

litter is what you throw in the trash, but you'll need about 4.7L of Dexron
Reply
Old Jul 12, 2021 | 6:30 AM
  #3  
William Kisselstein's Avatar
CF Pro Member
 
Joined: Aug 2013
Posts: 607
Likes: 80
Default

Scotty Kilmer says on older, high mileage transmissions that shift okay you may not want to change the fluid, because it has enough grit and worn particles in it that it keeps the trans working properly. You lose all that material out of it and it may slip and wear out faster.

The trans in there should be a TH350 or TH400 which are pretty tough units and any Dextron type fluid will be compatible. It's typically sold in quarts, but I'm not sure how many it will take, a web search will probably tell what the trans capacity is.
Reply
Old Jul 12, 2021 | 6:32 AM
  #4  
dtorres's Avatar
Thread Starter
CF Beginner
 
Joined: Feb 2021
Posts: 12
Likes: 0
Default

Originally Posted by mountainmanjoe
litter is what you throw in the trash, but you'll need about 4.7L of Dexron
so it's one gallon the replacement? and do you know the Dexron type?

thanks!
Reply
Old Jul 12, 2021 | 8:34 AM
  #5  
mountainmanjoe's Avatar
Super Moderator
 
Joined: Feb 2017
Posts: 6,207
Likes: 689
Default

any dexron you see (III and up)
I said 4.7L
One US gallon = 3.7L. You have internet. Use it lol.

I love Scotty, but he's full of $*&% in this situation
Reply
Old Jul 12, 2021 | 8:46 PM
  #6  
Uptownsport's Avatar
CF Junior Member
 
Joined: Jun 2021
Posts: 35
Likes: 1
Default

Incredible how many people get slushbox failures aft they meticulously change the fluid.

No Idea who Scotty is, but that makes as much sense as anything I've heard to explain the failures.

I replace the filter and filter fluid back in with a thick shop paper towel
Reply
Old Jul 12, 2021 | 11:02 PM
  #7  
mountainmanjoe's Avatar
Super Moderator
 
Joined: Feb 2017
Posts: 6,207
Likes: 689
Default

Originally Posted by Uptownsport
filter fluid back in with a thick shop paper towel
You will be one of those with a failure.
Reply
Old Jul 13, 2021 | 6:36 AM
  #8  
dtorres's Avatar
Thread Starter
CF Beginner
 
Joined: Feb 2021
Posts: 12
Likes: 0
Default

Originally Posted by mountainmanjoe
You will be one of those with a failure.
can you elaborate on that?
Reply
Old Jul 14, 2021 | 4:05 AM
  #9  
William Kisselstein's Avatar
CF Pro Member
 
Joined: Aug 2013
Posts: 607
Likes: 80
Default

Originally Posted by Uptownsport
Incredible how many people get slushbox failures aft they meticulously change the fluid.

No Idea who Scotty is, but that makes as much sense as anything I've heard to explain the failures.

I replace the filter and filter fluid back in with a thick shop paper towel
Google up Scotty Kilmer on Youtube.
Reply
Old Jul 14, 2021 | 9:08 AM
  #10  
pomerlo's Avatar
CF Junior Member
 
Joined: Sep 2019
Posts: 88
Likes: 24
From: Quebec, Canada
Default

If replacing your fluid cause a failure it means your tranny was on the last leg anyway.
Replaced mine on a 100k miles 4L80 and runs like new.


Reply

Thread Tools
Search this Thread

All times are GMT -5. The time now is 3:17 PM.