Fresh rebuild 727 lost reverse/first

Orange71SE · Jan 31, 2021

Just installed a freshly rebuilt 727 ( picked up from rebuilder 1 week ago). Installed it, filled it with atf+4. Put car on the ground and immediately did not have first or reverse. Dropped the pan and this is what i found.

dadsbee · Jan 31, 2021

If I paid a rebuilder I certainly wouldn't be the one been dropping the pan!

Certainly sucks though!

turbine68rt · Jan 31, 2021

Looks like a low-reverse band strut, but no reason to have two in there.

Slap Stick · Jan 31, 2021

Thats exactly what it is. The band is broken. BTDT.

R413 · Jan 31, 2021

Looks like the strut broke in half from here. If so that’s good and a new one can be n the car.

This is why you must have the idle low before selecting reverse, especially with cold fluid, pressure is the highest in reverse and cold fluid.

If you have the choke working adjust fast idle lower and kick it off fast idle before putting it in gear. I like to put it in drive first and then go right to reverse before idle jumps up. And do t rev it up in reverse either, makes the pressure rise a bunch.

Slap Stick · Jan 31, 2021

Did the transmission actually engage first or did it freewheel from the get go?

R413 · Jan 31, 2021

The strut should be 1” wide and. 1.25” long

Orange71SE · Jan 31, 2021

Slap Stick said:
Did the transmission actually engage first or did it freewheel from the get go?

Freewheeled for the start.

sam dupont · Jan 31, 2021

Put my Scout with a 907 into reverse and it only clunked. The shop said $300 to fix it, $600 to rebuild with an upgraded kit (2000).
If I rebuilt, they would fix the problem, which was reverse using only one of the two pumps, putting stress on the band. They were to do something to make both pump in Park. Without the modification, he said to always go into neutral before putting it in reverse.
No clue myself, but for $600 R&R, I wasn't too worried.

Dave6T4 · Jan 31, 2021

Orange71SE said:
Just installed a freshly rebuilt 727 ( picked up from rebuilder 1 week ago). Installed it, filled it with atf+4. Put car on the ground and immediately did not have first or reverse. Dropped the pan and this is what i found.

View attachment 1062460 View attachment 1062461 View attachment 1062463

Broken band apply strut for sure. This sometimes happens if you pull it into reverse when rev's are up. Make sure your engine is tuned up and running right so idle speed is correct. You can replace this strut by loosening lock nut and backing band adjustment screw all the way off, and popping new strut between band anchor and lever. Retighten adjustment screw to snug, and then back off 2 full turns. Crank down lock nut, and you are done. I always use the newer A518 pan gasket with the molded-in o-rings around all the bolt holes. These are more expensive than cork jobber gaskets, but they don't leak and are reusealbe.

Slap Stick · Jan 31, 2021

He says the transmission never engaged. I would assume no clunk, nothing.
But what would cause it to break if it never did anything?
I broke one but the trans had already engaged reverse then I nailed it. Boom!

Orange71SE · Jan 31, 2021

I also forgot to add that i have a shifter with a reverse lockout, so theres no way to even slam it in reverse to begin with. Either way, i will see if i can buy a new strut and slip one back in.

383man · Jan 31, 2021

Well the odd thing is even without the low/reverse band working it should still have low/first gear as the sprag (overrunning clutch) will hold just like when in drive in a stock trans. You should have still had first gear but just no low gear eng braking. You may have other problems also. Ron

moper · Feb 1, 2021

383man said:
Well the odd thing is even without the low/reverse band working it should still have low/first gear as the sprag (overrunning clutch) will hold just like when in drive in a stock trans. You should have still had first gear but just no low gear eng braking. You may have other problems also. Ron

yeah... no reverse means the band broke. No forward means either the sprag is dead, or the forward clutch isn’t working.
I hesitate to say take it back. But it needs to go back.

Fresh rebuild 727 lost reverse/first

Orange71SE

Well-Known Member

dadsbee

FBBO Gold Member

turbine68rt

Turbine Bronze Member

Slap Stick

Well-Known Member

R413

Well-Known Member

Slap Stick

Well-Known Member

R413

Well-Known Member

Orange71SE

Well-Known Member

sam dupont

Well-Known Member

Dave6T4

FBBO Gold Member

Slap Stick

Well-Known Member

Orange71SE

Well-Known Member

383man

Well-Known Member

moper

Well-Known Member

Similar threads