Minor transmission issue (see video)

[98 SNAKE EATER]

A few details on my car....

'69 Road Runner
440
TF727 w/reverse manual valve body
2800 stall
3.91 gears

Under 50% throttle, the trans shifts great and I have no issues :cool:

However, above 50% throttle, during the 2-3 shift, I get a 300-500 RPM spike before 3rd actually engages :confused:

Here's an old video that will give you an idea what I'm talking about:

http://www.youtube.com/watch?v=rRQXqXFgKtY

Fast Forward to 4:33, 5:50 and 8:55

Listen closely to the 2-3 shift and you'll hear the RPM spike....

It feels and sounds just like power shifting a manual trans.

There's no slippage in any gear when I flash it from low RPM's and the spike during the 2-3 shift under hard acceleration seems to be the only issue.

I'm hoping it's just a simple band adjustment, but open to other suggestions before I pull the pan.

 

[70rr-brian]

Try adjusting the shifter linkage.

 

[PDFROGMAN]

is this a stock unit that a RMVB was installed? who made/modified the VB?
gear overlap is an issue in a TF do you know which style kick down servo is in the unit?
is the car in NYC or Orlando I am located about hour north of NYC

 

[98 SNAKE EATER]

Try adjusting the shifter linkage.

Could you please elaborate?

is this a stock unit that a RMVB was installed? who made/modified the VB?
gear overlap is an issue in a TF do you know which style kick down servo is in the unit?
is the car in NYC or Orlando I am located about hour north of NYC

Not sure as the work was done before I or the PO

I live in NYC, but unfortunately, all my toys are here in Orlando

 

[PDFROGMAN]

some manufacturers require mods when using their VB HD returns springs in front clutch help prevent 2-3 bind up as the early kick down servo,
some manufactures require a small cup plug with a small orifice in case for the front clutch feed, By any chance does this VB have a Trans brake?
tough to diagnose with out knowing if you were here in NYC I would have told you if you pull the unit I would go through it for you

 

[98 SNAKE EATER]

No trans brake

 

[98 SNAKE EATER]

OK, I finally got around to adjusting the front band.

Started by cranking it in and got ~3.5 turns in before firm.

Torqued to 72 in/lbs., adjusted to ~2.5 turns out and lock it up.

Noticed a slight difference, but still getting a bit of flair

Here's a video from today (listen closely to the 2-3 shift)

http://www.youtube.com/watch?v=o_SMZMKFEAQ

 

[98 SNAKE EATER]

Another video.

http://www.youtube.com/watch?v=RgSrAZVHqA4

Flare is still there, but since it's been consistent and the filter didn't have any shavings the last time I pulled the pan, I think I'll just let it be.

 

[dvw]

What happens during the Torqueflite 2-3 shift? The K/D band releases, the front clutch applies. Everything that has been talked about, band adj, cupped orifice plug, extra springs in the front clutch all are done to eliminate overlap. None will reduce flare, only increase it. You have either,#1 leaking high clutch piston seals, #2 leaking seal rings on the reaction shaft support, #3 a valve body issue. You can air check the first two items if you remove the valve body. It is the 2nd hole over from the rectangular 2 holes along the front edge of the case.
Doug

 

[Garys1969RR]

My 69 RR with 451 was doing the same thing, except that It shifted good when cold, but the engine would rev up between 2nd and 3rd after it got warmed up. I have 2 trans coolers on it. Put in a trans go TF-2 valve body kit, same thing. So I put in a 69 Torque flite 727 from a 383 car, with the modified valve body, adj the bands and now it works great! Always suspected the high clutch was going bad. The trans fluid was smelling a little burnt, too. Will inspect the high clutch this winter and see if it was bad. Any burnt smell on the fluid?

 

[98 SNAKE EATER]

My 69 RR with 451 was doing the same thing, except that It shifted good when cold, but the engine would rev up between 2nd and 3rd after it got warmed up. I have 2 trans coolers on it. Put in a trans go TF-2 valve body kit, same thing. So I put in a 69 Torque flite 727 from a 383 car, with the modified valve body, adj the bands and now it works great! Always suspected the high clutch was going bad. The trans fluid was smelling a little burnt, too. Will inspect the high clutch this winter and see if it was bad. Any burnt smell on the fluid?

This does the same thing cold or hot (though I usually try to get her up to operating temp before ragging on her)

Fluid is clean and no shavings found in the screen the last two times I dropped the pan.