Questions about changing transmission

nick62087

Registered User
Im going to be changing the trans in my SC soon, its a 94 auto, 130k, mostly stock. The transmission that im planning to install is used, but it works. I have some questions about the install, maybe someone who has more experience could give me their opinions.

Should i change the fluid, or use the fluid thats in it?

Should i replace the pan gasket? or would that be a waste of time/money?

What do you guys think about putting in a drain plug? waste of time/money?

I understand there is a seal at the tail of the trans near where the driveshaft connects... should i replace this while the trans is out?

While i have the exhaust out, should i consider upgrading/ replacing hte resonator/ removing the cats? if so, what type of setup would you recomend?


THanks
Nick
 
Im going to be changing the trans in my SC soon, its a 94 auto, 130k, mostly stock. The transmission that im planning to install is used, but it works. I have some questions about the install, maybe someone who has more experience could give me their opinions.

Should i change the fluid, or use the fluid thats in it?

Should i replace the pan gasket? or would that be a waste of time/money?

What do you guys think about putting in a drain plug? waste of time/money?

I understand there is a seal at the tail of the trans near where the driveshaft connects... should i replace this while the trans is out?

While i have the exhaust out, should i consider upgrading/ replacing hte resonator/ removing the cats? if so, what type of setup would you recomend?


THanks
Nick

my answers are:
1. yes
2. yes and filter
3. would be nice but not neccesary
4. whole lot easier now
5. yes, i went the cat delete route with magnaflow resonator and mufflers, 2.25" downtubes to 2.5" dual in 3" single out split to two 2.5" tailpipes to mufflers.
 
....
Should i change the fluid, or use the fluid thats in it?

Change it. Most of it's going to end up on you, your clothes and the floor anyway. New filter is a must too.

....
Should i replace the pan gasket? or would that be a waste of time/money?

I'd replace it, unless you know someone has installed a reusable one lately that could be a factory original and is probably getting rather brittle by now.

....
What do you guys think about putting in a drain plug? waste of time/money?

You can get a B&M plug for about $8. It'll help prevent the fluid from getting all over you, your clothes and the floor *next* time you change the fluid. ;) Use some JBWeld to make sure it stays sealed, the little neoprene gasket on mine seeps a little even after it's been "resnugged". Ford sells a pan with the plug already in it but it's like $60.
 
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Should i change the fluid, or use the fluid thats in it?
Replace
Should i replace the pan gasket? or would that be a waste of time/money?
Nope. Not unless you can see a problem with the one it has.

What do you guys think about putting in a drain plug? waste of time/money?
Yes, these are the greatest things in the world.

I understand there is a seal at the tail of the trans near where the driveshaft connects... should I replace this while the trans is out?
If you can, yes. Also look into finding a clip for it, like some 4R70Ws have. I always had the problem of it vibrating out at high speeds...high being 130+.

If so, what type of setup would you recomend?
Whatever the law will allow. :) Your car will love some improved breathing.
 
I say all of the above AND replace the front seal behind the torque converter ans perlace the rear main engine oil seal behind the flex plate. They dont cost much ,easy to install and it can save you from pulling the tranny again. I do it on all trannys I pull.
 
First off ... why does your transmission need to be replaced ?? Failure ? Lost gears, is the fluid in it dirty now ?

You should flush the radiator, or buy a new one, and flush the cooler lines.

Add a transmission cooler

Use Mercon V Fluid

Upgrade to the 96+ Pan and Filter, there is a pan available with the drain plug like mentioned above, but not really necessary

Your Pan gasket is re-useable, shouldnt need to be replaced.

Definately replace the seal at the front pump. Its a common leak point after a new transmission has been installed. Make sure you RTV or use a new O ring on the Dipstick tube when you re-install it. If you replace the rear main seal on the engine, be sure to use new flexplate bolts.


Transmission that is used, but works - may just be a temporary solution. I wouldnt expect it to last forever so dont spend too much $$ on it.

- Dan
 
Thanks for all the suggestions!

The trans needs to be replaced because it doesn't work in 3rd or 4th gear. The fluid is brown and smells burnt.

I already have a new rad, i bought it months ago but hesitated to install it because i wasn't sure how long the trans was going to last. I was thinking i could just squirt the lines out with brakleen to clean out the old fluid.

I know that it's only a temporary solution, but the trans im putting in only has about half the miles as the one i had, and i dont want to spend too much money on the car.

I also purchased a new trans mount from SpinningWheels, the one i had looks pretty beat up.

Thanks for the input on replacing the seals.

Also, would you guys advise i keep the old trans and try to rebuild it? or just scrap it?

Thanks!
-Nick
 
Brake Cleaner, and compressed air works good for cleaning out the lines. It will be a good thing to use the new Radiator with the other transmission .. if your fluid is burnt and you dont have 3rd gear, its probably full of friction material. Direct clutch is probably all burnt up - common failure.

Scrap the 94/95 Transmission .. There isnt really anything worth salvaging from inside it - might want to keep the electronics like the TCC solenoid though.

- Dan
 
....Also, would you guys advise i keep the old trans and try to rebuild it? or just scrap it?

Thanks!
-Nick

The 99+ Mustang GT ones will fit our cars with some minor changes and are much improved over the 93-98 units in the internal parts area. You could put all the improved parts in the rebuild but the case would still be weaker than the new ones. Not a problem on a strictly street car but if you're wanting to rebuild it with some strip time in mind something to consider. Unless you want to do it strictly for educational purposes I'd say scrap it and find a Mustang one when this one gives out.
 
i thought the mustang GTs with the 4.6 had a different bolt pattern for the transmission? :confused:

They do have a different bolt pattern, you cant use a Mustang GT transmission. Just the V6 Mustang, non GT.

If you used a 99+ Mustang trans, you would need the appropriate speedo gear for the 8 tooth output shaft, or save the 7 tooth output shaft from your 94/95 tranny. And the electronic solenoids / wiring. You might want to save these parts from the old trans, plus the speedo, and the pan gasket + Magnet, sometimes you pick up a used transmission and it doesnt come with a gasket or magnet.
And the Mustang V6 transmissions sometimes dont have the same amount of clutch plates in the direct clutch, so you would want to rebuild that clutch pack for more durability.

- Dan
 
They do have a different bolt pattern, you cant use a Mustang GT transmission. Just the V6 Mustang, non GT.

.....

And the Mustang V6 transmissions sometimes dont have the same amount of clutch plates in the direct clutch, so you would want to rebuild that clutch pack for more durability.

- Dan


Oops. I'm con_fuz_ed again. I've got a Mark VIII too and the GT trans will work on it and 94+ V8 'Birds.

What Dan said is right. Though I thought I'd heard the 99-02 V6 transmissions would be fine behind a stock/street SC engine when the electronics are properly matched to the ECU being used?
 
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