1985 4+3 transmission fluid change
04-20-2017, 11:57 AM
#1
Drifting
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1985 4+3 transmission fluid change
I think it's time for some 'boring' maintenance on my Vette. I'd like to start by changing the transmission fluid. Sounds like it's a good idea to do the OD fluid at the same time.
There are a couple reasons to do this-
1: I've no idea how long it's been since it was changed, I don't know how the PO drove the car, so it's probably best to change it so I know it's been done.
2: I've no idea the full history of this car, and I think this is a good idea to take a look at the condition of the transmission, and possibly get ahead of problems before something bad happens.
I'm not currently having any big transmission issues, but a fluid change can't hurt, and then I'll know it's done and it's done right.
Here's my issue, though. I've never touched a transmission before in my life. Can someone help me with this job, like I'm an idiot? From what I read online, it's as simple as drop the pan, replace the filter and gasket, put the pan back on, and add fluid. Sounds simple, but I don't want to start screwing with my transmission without a good understanding of what I'm doing.
I would really appreciate links to parts, step-by-step instructions for the manual transmission and overdrive unit, and fluid recommendations. I don't want to start a war over the 'best' fluid-anything decent will work. I don't race this car so I'm not terribly concerned about it. I know how to jack up the car, but other than that, please don't assume I will know anything about what I'm doing. I'm certainly not a complete idiot, but as stated, I've never touched a transmission before.
Thank you!
There are a couple reasons to do this-
1: I've no idea how long it's been since it was changed, I don't know how the PO drove the car, so it's probably best to change it so I know it's been done.
2: I've no idea the full history of this car, and I think this is a good idea to take a look at the condition of the transmission, and possibly get ahead of problems before something bad happens.
I'm not currently having any big transmission issues, but a fluid change can't hurt, and then I'll know it's done and it's done right.
Here's my issue, though. I've never touched a transmission before in my life. Can someone help me with this job, like I'm an idiot? From what I read online, it's as simple as drop the pan, replace the filter and gasket, put the pan back on, and add fluid. Sounds simple, but I don't want to start screwing with my transmission without a good understanding of what I'm doing.
I would really appreciate links to parts, step-by-step instructions for the manual transmission and overdrive unit, and fluid recommendations. I don't want to start a war over the 'best' fluid-anything decent will work. I don't race this car so I'm not terribly concerned about it. I know how to jack up the car, but other than that, please don't assume I will know anything about what I'm doing. I'm certainly not a complete idiot, but as stated, I've never touched a transmission before.
Thank you!
04-20-2017, 01:47 PM
#2
Team Owner
Changing the ATF fluid in the OD unit is not hard at all and it's just like you have found out. It would help to get the car as high as possible so you can access the pan bolts. There's not a lot of fluid in the pan (roughly 2 quarts) so a small drain pan is all you need to catch the old fluid.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
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Bfenty (04-20-2017)
04-20-2017, 01:59 PM
#3
grommets:
https://www.corvetteforum.com/forums/c4-tech-performance/3936286-hey-4-3-owners.html
https://www.corvetteforum.com/forums/c4-tech-performance/3936286-hey-4-3-owners.html
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Bfenty (04-20-2017)
04-20-2017, 02:07 PM
#4
Drifting
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Location: Nashville TN
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Changing the ATF fluid in the OD unit is not hard at all and it's just like you have found out. It would help to get the car as high as possible so you can access the pan bolts. There's not a lot of fluid in the pan (roughly 2 quarts) so a small drain pan is all you need to catch the old fluid.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
04-20-2017, 02:18 PM
#5
Melting Slicks
Changing the ATF fluid in the OD unit is not hard at all and it's just like you have found out. It would help to get the car as high as possible so you can access the pan bolts. There's not a lot of fluid in the pan (roughly 2 quarts) so a small drain pan is all you need to catch the old fluid.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
Start by removing the fill plug! If you can't do that, there will be no easy way to refill the OD. Remove the bolts but leave two corner bolts loose. Once you start to pull the pan off the housing, the fluid will start to drain out. Once that finishes, pull the last of the bolts to remove the pan. Pull the filter straight down; it's held in place by a rubber grommet. Save the grommet!
Clean all of the gasket material from both the pan rail and the rail on the OD housing. Clean the pan using a solvent or even brake parts cleaner. Remove the magnet and clean it too. Replace in the same spot in the pan. Make sure the pan rails are straight and the edges around the bolt holes are level with the rail.
Here's some part numbers for a new filter. The filter is the same one used in some Ford FMX transmissions found in early 70's Mustangs, Torino's and even a few F-150's:
Carquest 85926 (now Advanced Auto Parts and the p/n may be different
AC Delco TF 184
Fram FT 1024
NAPA ATP14717
Ford D0AZ-7A098-A
These should run about $8 to $10. The do not come with a grommet so save the old one.
Use a good black RTV sealant on the pan rails making sure you go around the bolt holes. The bolts don't need to be very tight but they should be tightened equally.
Use non-synthetic ATF such as Dexron III. You should be able to find that at any parts store. You will need a pump to get the fluid in. Use one that screws onto the bottle and will allow for attaching a short piece of tubing.
That sum's it up very well, but I will add that if your O/D has not been Serviced in awhile it will have a very nasty ATF in it So don't start wondering if someone filled your O/D with 90 weight gear oil. If your fluid is nasty you may want to remove the cooler lines from the O/D unit and flush them out with clean ATF otherwise your just pumping a mouth full out garbage into your now fresh clean pan.
now to be Clear your transmission is made of 2 parts the Front 1/2 is your T-10 Main box Unit(closes to Clutch) Gears 1 thru 4 that Transmission takes a Standard type of Gear oil (the stinky Stuff)
The Back 1/2 is your Over Drive unit (closes to Drive shaft)has a oil pan that take the ATF.
Before you try to do any of the work I can't stress enough that you have the Correct 9/16 socket for a Square drive plug, as others have stated make sure you can get the needed plugs out before Draining.
Last edited by s carter; 04-20-2017 at 02:24 PM.
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Bfenty (04-20-2017)
04-20-2017, 02:25 PM
#6
save the next owner, or yourself, a hole in the head and do not use RTV. Use a cork gasket and Hilomar.
rtv is a product of the devil, where his victems sit there all day and scrape it off places like valve cover gasket's, water pump gaskets, and gaskets, hose fittings, God knows where else.
lol. i hate rtv with a passion!! if you cant tell!
and do not over tighten the pan bolts. Most 4+3 pans have been over tightened and they are dimpled towards the mating surface and may need to be flattened. use your head here.
rtv is a product of the devil, where his victems sit there all day and scrape it off places like valve cover gasket's, water pump gaskets, and gaskets, hose fittings, God knows where else.
lol. i hate rtv with a passion!! if you cant tell!
and do not over tighten the pan bolts. Most 4+3 pans have been over tightened and they are dimpled towards the mating surface and may need to be flattened. use your head here.
Last edited by VikingTrad3r; 04-20-2017 at 02:26 PM.
04-20-2017, 02:25 PM
#7
Drifting
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That sum's it up very well, but I will add that if your O/D has not been Serviced in awhile it will have a very nasty ATF in it So don't start wondering if someone filled your O/D with 90 weight gear oil. now to be Clear your transmission is made of 2 parts the Front 1/2 is your T-10 Main box Unit(closes to Clutch) Gears 1 thru 4 that Transmission takes a Standard type of Gear oil (the stinky Stuff)
The Back 1/2 is your Over Drive unit (closes to Drive shaft)has a oil pan that take the ATF.
Before you try to do any of the work I can't stress enough that you have the Correct 9/16 socket for a Square drive plug, as others have stated make sure you can get the needed plugs out before Draining.
The gear oil for the T-10 piece-is that just going to be something like 80w90 oil? Again, never messed with a transmission so I've no idea.
Other than the filter and gasket, anything else needed for the t-10? any pitfalls a newbie could fall into? (I've already been warned about over-tightening the bolts lol).
Where is a good place to buy the gaskets and filters needed for both the OD and the T-10?
Thanks for the tip on the drain plug. That could be a very bad thing if I can't get it out...
04-20-2017, 03:19 PM
#8
Melting Slicks
I'm sure the OD fluid is pretty nasty, considering the state of the car when I bought it.
The gear oil for the T-10 piece-is that just going to be something like 80w90 oil? Again, never messed with a transmission so I've no idea.
Other than the filter and gasket, anything else needed for the t-10? any pitfalls a newbie could fall into? (I've already been warned about over-tightening the bolts lol).
Where is a good place to buy the gaskets and filters needed for both the OD and the T-10?
Thanks for the tip on the drain plug. That could be a very bad thing if I can't get it out...
The gear oil for the T-10 piece-is that just going to be something like 80w90 oil? Again, never messed with a transmission so I've no idea.
Other than the filter and gasket, anything else needed for the t-10? any pitfalls a newbie could fall into? (I've already been warned about over-tightening the bolts lol).
Where is a good place to buy the gaskets and filters needed for both the OD and the T-10?
Thanks for the tip on the drain plug. That could be a very bad thing if I can't get it out...
Standard 80w/90w is fine.
Last edited by s carter; 04-20-2017 at 03:21 PM.
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Bfenty (04-20-2017)
04-20-2017, 04:36 PM
#9
Drifting
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Thanks all, I think I've got a pretty good idea of what I'm doing now. I'll try to remember to take pics of what I pull out of there.
Probably do the rear differential at the same time-anybody know where I can get the additive I'll need for that? I've seen dealership recommended?
Probably do the rear differential at the same time-anybody know where I can get the additive I'll need for that? I've seen dealership recommended?
05-01-2017, 02:31 PM
#13
Team Owner
If you can't get the fill plug out, it will be really hard to refill the trans....As far as using RTV sealant, finding the OD pan gasket can be a chore. The various Corvette accessory catalogs sell the filter kit (filter and gasket) but at 3 times the price of just the filter. Most of the big chain parts stores will either have the filter in stock or can get one in a day or two.
With a cork gasket, I like to use Coppercoat from a spray can. It does seal well but you really need to make sure the pan rails are clean and flat. RTV sealant will seal uneven surfaces better. And it can be easily removed with brake parts cleaner or Acetone.
Last edited by c4cruiser; 05-01-2017 at 02:36 PM.
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Bfenty (05-01-2017)
05-01-2017, 03:51 PM
#14
Drifting
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Make sure you are able to remove the fill plug before removing the drain plug!! If you can't get the fill plug out, it will be really hard to refill the trans....
As far as using RTV sealant, finding the OD pan gasket can be a chore. The various Corvette accessory catalogs sell the filter kit (filter and gasket) but at 3 times the price of just the filter. Most of the big chain parts stores will either have the filter in stock or can get one in a day or two.
With a cork gasket, I like to use Coppercoat from a spray can. It does seal well but you really need to make sure the pan rails are clean and flat. RTV sealant will seal uneven surfaces better. And it can be easily removed with brake parts cleaner or Acetone.
If you can't get the fill plug out, it will be really hard to refill the trans....As far as using RTV sealant, finding the OD pan gasket can be a chore. The various Corvette accessory catalogs sell the filter kit (filter and gasket) but at 3 times the price of just the filter. Most of the big chain parts stores will either have the filter in stock or can get one in a day or two.
With a cork gasket, I like to use Coppercoat from a spray can. It does seal well but you really need to make sure the pan rails are clean and flat. RTV sealant will seal uneven surfaces better. And it can be easily removed with brake parts cleaner or Acetone.
05-01-2017, 04:43 PM
#15
Team Owner
The Carquest part number I put in the post was the correct one for my old '87 4+3. The local Carquest stores have been bought out by Advance Auto Parts but the part number should be the same.
If your parts store has FRAM filters , look thru the catalog for a trans filter for an early '70s' Fairlane, Merc Cougar, Ford Mustang and some Ford F-150's that use the Ford FMX transmissions. You could even go to a local Ford dealer and have the parts guy help you.
Last edited by c4cruiser; 05-01-2017 at 04:43 PM.
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Bfenty (05-01-2017)
05-01-2017, 11:30 PM
#16
Drifting
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See Post #2. The part numbers should be valid. The problem with many chain parts store clerks is that have to depend on getting the year, make and model, and trans type in order to go find the part on a shelf.
The Carquest part number I put in the post was the correct one for my old '87 4+3. The local Carquest stores have been bought out by Advance Auto Parts but the part number should be the same.
If your parts store has FRAM filters , look thru the catalog for a trans filter for an early '70s' Fairlane, Merc Cougar, Ford Mustang and some Ford F-150's that use the Ford FMX transmissions. You could even go to a local Ford dealer and have the parts guy help you.
The Carquest part number I put in the post was the correct one for my old '87 4+3. The local Carquest stores have been bought out by Advance Auto Parts but the part number should be the same.
If your parts store has FRAM filters , look thru the catalog for a trans filter for an early '70s' Fairlane, Merc Cougar, Ford Mustang and some Ford F-150's that use the Ford FMX transmissions. You could even go to a local Ford dealer and have the parts guy help you.