2nd gear brake away / no downshift to first

[david hill]

Haven't seen this before maybe one of our members has seen this. On morning cold starts this transmission when placed in drive will be in 2nd gear on cold brake away. It also will not downshift to first gear from any speed. If manually shifted to first gear it will go into first gear, but have a late shift to 2nd gear. The trans fluid is a little dark in appearance. the fluid doesn't smell burnt. Shifting from drive to reverse are crisp and solid. Fluid level is full and checked in neutral Any ideas what causing this.

 

[CBODY67]

The only "breakaway" in a TF is in "D" with it starting in Low gear, as is normal. Not sure about the late shift (as in non-responsive upshift?) from 1-2 starting in "1". IF something is not free enough when the trans is cold, which the cleaning will hopefully take care of, then it might be a shuttle valve spring or such?

Is the kickdown linkage still at the factory setting? Just curious.

Might try some atf "cleaner" additive, run it for a while, then change the fluid and filter. We used to use Berryman's B-12 quart as such an additive in the 1960s and later. Basically a varnish dispersant, which cleans things up very nicely. Usually about 30 minutes run time and the fluid would be black. Then a good "drip drain" followed by a new filter and quality fluid and things were ready to go again.

The "burnt smell" usually indicates heat and friction slippage only. Although heat can change the color a bit, by itself.

Just some thoughts,
CBODY67

 

[1970FuryConv]

I wonder if there is a problem with the accumulator. I know you can drop the valve body and remove the accumulator spring. You increase 1-2 shift intensity by removing spring at accumulator between front and rear servos.

Kickdown band could be out of adjustment.

I'd try the cleaning solution that Willis recommended 1st.

 

[CBODY67]

Also, if you look at the high-color schematic in the FSM, there are different sections of the trans involved when the selector is in "D" and "1", at takeoff. So the delayed/late 1-2 upshift when going from manual Low to upshift might involve other things than if the delayed upshift happened with the selector lever in "D".

CBODY67

 

[cbarge]

Do you start engine in Park?
I prefer running a cold engine in Neutral to circulate the trans fluid during warm up.
It does make a difference.
Otherwise start with the simple schtuff, adjust the kickdown and recommend servicing the trans if it has been a while since last service.
Hope this helps

 

[70NEWYORKER]

Could it be something in the governor?..weak springs, sticking weights, loose mounting bolts?

 

[david hill]

Here are the results after testing. The governor pressure didn't change w/ a increase in speed. The kick down servo slow to apply w/o the accumulator spring. With the lack of down shifting coming to a stop the valve body was removed. the shuttle valve was jammed shut and w/ some light tapping w/ a brass punch was freed up. Disassembled the valve body to check for debris being present, none-found. Unexpected was a modification to the transfer plate was found. It is like a mod done in Trans Go shift kit from years ago. If one of you has the Trans Go instructions it would help in seeing what been done. As I remember there were different governor plugs, + shift valves and springs. Info now would be very helpful.

 

[CBODY67]

I kind of doubt the lack of an accumulator spring is causing the slow servo apply mentioned. Removing the accumulator spring takes that little bit of "apply" cushioning out of the mix, for quicker and firmer "apply" when that circuit is energized with fluid pressure. Per the old Direct Connection Race Manual and the basic "shift kit" from Mopar Perf.

Glad you got things freed-up!

Enjoy!
CBODY67

 

[Loadrunner]

I learned to rebuild TQ's in school, 2nd year transmissions and drivetrain.

I started building them in my backyard and used Transgo shift kits only, and would recommend it anyday over stock valve body/shifts, much better shifts and it makes the transmission last by eliminating slippage.

I should shift kit my 727 ;]

 

[1970FuryConv]

I learned to rebuild TQ's in school, 2nd year transmissions and drivetrain.

I started building them in my backyard and used Transgo shift kits only, and would recommend it anyday over stock valve body/shifts, much better shifts and it makes the transmission last by eliminating slippage.

I should shift kit my 727 ;]

TQ is usually thermoquad in my lexicon.
What is a TQ transmission?

 

[Loadrunner]

Meant TF, typing too early.

 

[1970FuryConv]

Thanks. Sometimes I need a stewardess to stop by my desk and ask, "Coffee anyone?"

This happens regardless of time of day.