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727 Problem with 3rd gear

Lisa

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I have some trouble with The TF727 of the67 Coronet. Long Story Short......when my Girl brought The car The 3rd Gear was shot. So i brought a b&m Master mit and a new converter and rebuilt The Transmission. Now The car Runs Perfect 1st 2nd and Reverse. 3rd Starts to slip...... Oil pressure should be fine cause it takes Off strong and 1-2 shift is also very Good and Tight. So my opinion is that The Valve Body has a Problem with 3rd Servo. What do you think?
 
I have some trouble with The TF727 of the67 Coronet. Long Story Short......when my Girl brought The car The 3rd Gear was shot. So i brought a b&m Master mit and a new converter and rebuilt The Transmission. Now The car Runs Perfect 1st 2nd and Reverse. 3rd Starts to slip...... Oil pressure should be fine cause it takes Off strong and 1-2 shift is also very Good and Tight. So my opinion is that The Valve Body has a Problem with 3rd Servo. What do you think?
Is it slipping or prematurely trying to kick down?
 
Did you air check the circuits, could be a leak at the sealing rings on the reaction shaft, maybe enough flow for reverse but not enough for high gear to hold properly.
 
No, it doesnt try to Kick down. It is Slipping.
1st and Second also holds torque well. I can floor it in First go up to 5500rpm and Shift Manual into 2nd. Shift Good and firm and holds well at WOT. But as it goes in 3rd it Slips BAD.... I would destroy The clutch Discs if i would Stay on The throttle.
 
Check your shifter linkage adjustment. Feel the fit in each gear of the shift rod in the lever on the trans. Been there.
 
Check your shifter linkage adjustment. Feel the fit in each gear of the shift rod in the lever on the trans. Been there.
Sorry. Maybe a stupid question but but if i Put the shifter into D it runs Clean First and second and Slips as it shifts into 3rd.
What do you mean?
 
I believe you're going to pull this trans out anyway but, pull the VB first and air check as justcruin asked earlier. You can hear a "thud" as the front clutch pack applies. If considerable air noise is present-something is leaking.
Mike
 
does it slip throughout 3rd? or just into third
Yes. Slips throughout 3rd. If i Close throttle Shift from 2 to D and just cruise i can rum 60mph without slip. But as i Start to open The throttle just a little Bit more...as torque comes up it Slips again. And no Not because it wants to Kick down. Less throttle less slipping more throttle more slip. Just like a Manual Trans with a woren out clutch
 
I believe you're going to pull this trans out anyway but, pull the VB first and air check as justcruin asked earlier. You can hear a "thud" as the front clutch pack applies. If considerable air noise is present-something is leaking.
Mike
I'll Check The VB First. I paid attention to clearence of each clutch during Assembly. They we're all Good. I Think there Mist ne a reason that i pulled the trans with a burnt 3rd and now it does it again. Previous owner Drive it with Oil very low. I thought this was The reason for the damage. But i have the right Oil Level in.... I also Think that The Problem is in The Valve Body. Some haircrack or anything that gets Air in The 3rd Gear or looses pressure to fully engage
 
The kickdown linkage is from carb to the small lever above shift lever. At full throttle that lever should all the away to back of car. Cooked a set of clutches, learned the hard way.
 
When you rebuilt the trans, did you dis-assemble the front drum and replace the piston lip seals, or just replace the clutches and steels?
Just asking because I have ran into that problem before, where the "Rebuild" did not replace the piston seals.
 
I'll Check The VB First. I paid attention to clearence of each clutch during Assembly. They we're all Good. I Think there Mist ne a reason that i pulled the trans with a burnt 3rd and now it does it again. Previous owner Drive it with Oil very low. I thought this was The reason for the damage. But i have the right Oil Level in.... I also Think that The Problem is in The Valve Body. Some haircrack or anything that gets Air in The 3rd Gear or looses pressure to fully engage

Valve bodies are prone to cracking.
Mike
 
Bands adjusted right? That's if the air check is good.

Mike is right, on the valve bodies. When you overhauled it, did you go completely through the valve body, check each valve and bore?
If it's cracked, you should have seen it.
 
When you rebuilt the trans, did you dis-assemble the front drum and replace the piston lip seals, or just replace the clutches and steels?
Just asking because I have ran into that problem before, where the "Rebuild" did not replace the piston seals.
I replaced all seals and rings. But i will Check with Air.
 
Valve bodies are prone to cracking.
Mike

I had a crack in the wall of the transfer plate, and lost 3rd gear totally. Happened out of town, but the '68 Polara must have had 2.73:1 gears as it ran 55 mph in second gear just fine. I was able to fix the valve body with JB-Weld which seemed to work fine for the 500 miles I drove the car before getting a replacement valve body.
 
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