727 shift point seems too high - seeking help

[43tutor]

My first real road test in my 72 SSP was this past weekend after 2 1/2 years. The 2-3 shift point seems too high.

470 stroker, 2800 stall converter, 3:55 suregrip, 225 70R14 tire (26.5" diameter). Planning to change to a 15" wheel at some point.

I rebuilt the entire transmission with all new key items. Installed a Trans-Go TF-2 reprogramming kit and followed the Trans-Go instructions to the letter. I was meticulous with all the cleaning and assembly so I do think there is any debris in the valve body but there is always that chance.

I believe the speedometer to be fairly accurate but I have not verified. I did install a new 36 tooth gear in the tranny during the rebuilt to accommodate the tire size and rearend gear change. When driving the car I get a nice smooth firm 1-2 shift around 20 MPH. The 2-3 shift doesn't happen until around 50 MPH. Is this normal for my setup, it seems too high for MPH for 2-3 shift.

I adjusted the kickdown linkage per FSM. I adjusted the shift selector linkage starting in the neutral position. I have verified the kickdown band adjustment from 72 in/lbs. and backing off 2 1/4 turns.

My thinking is the governer side line pressure is low and can't overcome the throttle pressure to make the shift until later when the road speed higher. Is my thinking correct on this?

 

[mentor70]

you may have a hung up governor, or a fluid pressure issues as you stated.

you may want to back off the adjustment off the carburetor a couple of turns and see what that does first, if things dont change at all, its most likely inside the trans.

 

[mopar 3 B]

Have you checked line pressures. Low governor pressure will prevent 2-3 shifts will not delay them. If it shifts up when taking your foot off the gas downshift linkage is still to tight.

 

[moper]

^^ x2.
operating pressures need to be checked and the line pressure adjusted. My impression is the line pressure might be a hair high. If the kickdown adjustment cannot correct it without hurting the 1-2 upshift that might be it. only way to know for sure is to put a gage on them.

 

[lewtot184]

i have two torqueflites, one a tf1 the other a tf2 kit. they don't like the same throttle pressure adjustments. the tf2 trans has to be backed off on the throttle pressure to prevent excessive upshift speeds. start backing the throttle pressure down to get 1-2 shifts at 15mph and 2-3 at 25mph. this is at light throttle.

 

[383man]

With that kit in it it may not shift at the same speeds the stock setup would. Even if line pressure is high it will effect gov and throttle pressure both so really should not change the shift points much since they work against each other. Low gov pressure will effect all shifts not just the 2/3 shift. Even if gov pressure is low it may still shift into third but at a much higher road speed. Any adjustment on the trans throttle pressure will change both the 1/2 and 2/3 shift some. And you dont want the throttle pressure to low as it also effects the trans line pressure since it also goes to the pressure regulator valve. If you lower the throttle pressure any make sure you do not get any flare on the 1/2 shift on light throttle as if you do then the throttle pressure is to low and raise it back up some. You may have to live with the 2/3 shift a little high with that kit in there or without modifying it some. If you changed the gov valves to lower the 2/3 shift just remember it will also lower the 1/2 shift as the same gov pressure works on both the 1/2 and 2/3 shift valves as does the same throttle pressure. You can try lowering the throttle pressure a little but it will lower both shift points and if it gets any flare on the 1/2 shift then you went to low on throttle pressure. Ron

 

[lewtot184]

something to think about on those tf2 kits. the spring at the line pressure adjustment is changed to a heavier spring and the adjuster is backed all the way off. i'm thinking the line pressure is increased by the heavier spring and this effects the throttle pressure adjustment at the carb. if i adjust the tf2 trans i have the way i adjust the tf1 the tf2 trans won't upshift at WOT and at normal driving there's a lot of shift over lap.

 

[43tutor]

Thanks for the replies and great information. All great points and just confirms what I was thinking. I will make some adjustments this weekend and post the results.

 

[Bb70charger500]

Sounds like we're all on the same page on this . I agree with everyone else . I had a javilen that was like this a few adjustments and she was good as new.
Good luck

 

[43tutor]

I made some throttle linkage adjustments (moved the kickdown rod about 1/4" forward, reducing throttle pressure) and drove the car again. Shifts didn't change much, maybe a little lower on the 2-3 shift. Car has about 5 miles since the rebuild. I will get it out and put a few more miles on it and make some further adjustments. Stay tuned for updates.

 

[themechanic]

With a light peddle (ie. normal driving) my TF2 kit shifts from 2-3 around 45-50 mph when cold but lowers after the first or second time going into 3rd.

 

[43tutor]

I drove the car about 8 miles tonight. Normal throttle 2-3 shift still around 50 MPH. Same as themechanic's car in post above. As the car reaches 50 MPH I can slightly lift off the pedal and it shifts into 3rd. So that tells me it is the throttle pressure along with the stiffer spring of the TF2 kit. Once it shifts into 3rd I can slow down to around 30 before it down shifts back into 2nd.

 

[mopar 3 B]

Back the linkage off at the carb till it shifts where you want it to. Was never stated is it the 3 section linkage or 1 section?

 

[themechanic]

There is more than one option in the installation instructions for the Transgo TF2 Kit. I chose the lighter one as I ddn't want it to shift too harsh. Did you install the hard shifting option(s)?

 

[evilmopar]

I just got my TF2 kit in my 1964 TF727. And i adjusted the line pressure on the valvebody, i gave it 2 turns in. And then i hade to adjust the kickdown leaver to get it shift properly. It shifts 1-2 in 20mph and 2-3 in 45mph. But i have an issue with the down shifting when i slow down. It doesn´t shift down properly but i think it´s because the 3000prm converter.. It´s messing a bit with the pressure in the tranny when driving under 3000rpm.