Jim Bob The Dancing Bear
Well-Known Member
I did drive to work this morning.
No third gear
- Thread starter Jim Bob The Dancing Bear
- Start date
Garys1969RR
Well-Known Member
My 727 was shifting into 3rd, but then running away in 3rd gear, especially under hard acceleration. All the other gears worked ok. Turns out the high clutch was bad, which is the front clutch. This one is disengaged in second, but engages in third. As opposed to the rear clutch, which is engaged for all gears except reverse. This front clutch, I believe, is the weakest link in this otherwise bulletproof transmission.
Didn't try the put in park trick. I would never do that at 40 mph but maybe a roll in and out of park. It's your trans.
I would check the gear selection linkage before digging in that deep. Make sure the adjustment on the rod from the transmission lever to the bellcrank hasn't slipped or come loose and the lever is actually engaging 3rd gear position in the transmission.
miller
Well-Known Member
Suggest when you drain the fluid, run a magnet through it, looking for metal. If something is busted in the trans, that will be a sure sign. While you have the valve body off, you'll be able to look over most, but not all, of the internal parts.
Good luck on it!
Garys1969RR
Well-Known Member
Good suggestion, Miller. Also, look in the bottom of the pan for friction material that may have come off one the clutch packs, in the event of a failure. I have seen this more than once, when a trans was having problems.
It is correct that the forward clutch is applied in both 3rd and reverse. However the apply pressure is much higher in reverse than in 3rd. Drop the pan. What is floating around in there? Brown leafy substance? High/rev clutch is probably toast. Cause? Worn stator support rings, high gear drum ring bore grooved, high clutch piston seals torn or worn. No debris? Pull the valve body and check the 2/3 shift valve for sticking.
Doug
Doug
miller
Well-Known Member
Right on the mark! Know that the clearances in the shift body are very close. Doesn't take much to clog it, where the valves stick.
Can't say that's it, just one of a handful...
Jim Bob The Dancing Bear
Well-Known Member
I pulled the valve body yesterday. Nothing out of the ordinary in the pan.
I cleaned the valve body and air tested the transmission. It took a couple of hits of air to get one of the clutches to actuate. I assume it was stuck from sitting. I got it all back together and it is over reving really bad. I need to readjust the shifter and try again today. Plus it was a quart low when I got back from my test drive. It did shift into third this time.
I cleaned the valve body and air tested the transmission. It took a couple of hits of air to get one of the clutches to actuate. I assume it was stuck from sitting. I got it all back together and it is over reving really bad. I need to readjust the shifter and try again today. Plus it was a quart low when I got back from my test drive. It did shift into third this time.
That's progress. I don't know - a full quart low may be enough to start causing some operational issues. Mine seems to be doing fine at a pint low.
Is it over-reving at part throttle shifts, full throttle, or both?
Is it over-reving at part throttle shifts, full throttle, or both?
Garys1969RR
Well-Known Member
After it shifts into third on part throttle, or low engine torque situations, then add more throttle while in third, but don't open it up all the way where it goes into passing gear. If it starts slipping, or shifts back into second, it's prob your high clutch. Make sure the fluid is up to the full mark, although I have run mine a quart low without any problems.
Garys1969RR
Well-Known Member
If it's still over revving in third, or running away, you should pull the transmission. Remove the front pump, and then the high clutch/and drum that the kick down band circles around. Inspect the front clutch friction discs, and the plates for burning or scorching. This could very well be where the problem is.
Jim Bob The Dancing Bear
Well-Known Member
Pulling the transmission will not happen until I am ready to upgrade.
I readjusted the shifter linckage and the kick down linckage. I now have full throttle and it has a lot more power down low.
I have all three gears.
I was two quarts low so it is now running better. Each time I go through the gears, just regular driving, it shifts better. It isn't perfect yet but is getting better as I drive it.
Hopefully a few more runs through the gears and it will be right as rain.
Thank you everyone for your input.
I readjusted the shifter linckage and the kick down linckage. I now have full throttle and it has a lot more power down low.
I have all three gears.
I was two quarts low so it is now running better. Each time I go through the gears, just regular driving, it shifts better. It isn't perfect yet but is getting better as I drive it.
Hopefully a few more runs through the gears and it will be right as rain.
Thank you everyone for your input.
Garys1969RR
Well-Known Member
Make sure the kickdown linkage is all the way back at full throttle. I set mine all the way back to the stop point, when the throttle is wide open.
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