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727 trans no forward gears

11K views 14 replies 4 participants last post by  Crosley 
#1 ·
I have a rebult 727 trans new clutches, plates, bushings, pump
forward/reverse bands, tourqe converter...
But i get no forward gears, only reverse.
Anyone have any sugestions as to want i shoud check or be looking for.?

Thanks
 
#4 ·
It has the proper seals, I replace every thing clutches seal bearings bushings, front pump gears, tourqe converter, its not a lockup unit, i did not replace the value body but cleaned it good befor replacing.
I have no forward gears at all no 1,2,3 manual shifting or not, it seems like a fluid presure problem to me but i hate to pull it out till i know were the problem is.
Are the ways to test the presure while running other then the coolant line.

Thanks
 
#6 ·
yes i replaced the piston seals and the spline was fine...
I started pulling it out today will be tearing it down to see what might be the problem, I am going to check the seal in the front cluches to see if that maybe got messed up, it seems to have good fluid presure and if the seal is broke the clutches won't engage, correct me if i an wrong...
 
#9 ·
I did an air pressure test and the rear cluches are not moving in case... then i pulled the pump and fount and rear cluches, no i did a bench test still on rear cluch movement, i then disasembled the rear clutchs and did a presure test i get no air presure going to the rear cluch, i will get it sometimes but not most of the time the holes are not clogged its almost like the proper holes are not lined up i tryed it with the shim and without but the same result its a new front shaft, i just can't tell if all the holes line up after i lay the clutches onto the pump for testing.....

Thanks gary
 
#10 ·
Do this.
Place the pump face down in a vice.
Don't tighten it too much, just enough to hold.
Install both drums.
Air check the system.

You should be able to apply the forward clutches by placing a finger over one hole in the input shaft and applying air pressure to the other.
You do have the metal sealing rings installed on the input shaft?
They are the correct size?
 
#11 ·
I tried that but no good, after taking a closer look at the input shaft I noticed there is no hole between the 2 metal seal rings, looking at the picture it appears to have a hole there but had to tell, if it indeed needs a hole can i drill it?... It's a new input shaft i took and had pressed in...
 
#13 ·
So are you saying i can't drill it, I have had the shaft for 6 months or more and will not be able to return it.... I looked in another trans book and indeed it showed the two shafts the pre 1978 had a hole and 78 and later had no hole mine is a 1977.... so i guess this might explane the problem...
 
#15 ·
If you have a mismatch of the input shaft / drum design and the pump cover ( aka stator support) ..... it will not function correctly.

The clutch pack is fed differently with sealing rings in different locations
 
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