input shaft end play

[chargerdon]

I rebuilt my 904, and followed the shop manual on measuring both rebuilt clutch packs and have the proper clearances there.   Before I started my input shaft end play was about .060 or right between the manuals .030 to .090 end play.   Also, I measured the clearance on the output shaft in the tail section at the snap ring and it was right on.   I was careful to put all of the thrust washers back into their proper places.

Once I put it all back together, I don't seem to have any input shaft end play at all.   Any suggestions on where to look for the problem?? 

[1 Wild R/T]

likely a clutch disc didn't get stacked properly...

[chargerdon]

I presume you mean that in putting it together, on of the clutch pack plates didn't drop in all the way, either the front pack onto the rear pack, or the input shaft assembly all together.   How do you know when they all have "dropped iN"??  I cant find any good references on knowing that.    is there a way to tell without putting the pump back in?

[1 Wild R/T]

Pump has to come out.. If as I suspect one disc isn't properly aligned the pump is putting pressure on the splines that drive the hub....
It's easy to miss a disc when stacking components, the trick is looking how deep the teeth of the front clutch drum engage the sun shell... The teeth can't be pushed out at all, one disc misaligned on either clutch pack will cause the teeth of the clutch drum to not fully engage... The front pump forces the drum into the sun shell so it needs to be pulled to get an accurate inspection....

[chargerdon]

I pulled the pump and the input shaft assembly.   None of the teeth of the clutches were damaged.   In pulling the pump the entire assembly came out together.  One thing that definitely stood out was that the new bushings are tight..  so tight that The weight of the input assembly was not enough to pull the pump off of it.  To get the input shaft off from the pump i had to tap on it with a rubber hammer.  .  Hmmm

So started again, This time I actually rubbed some grease rather than just transmission fluid on all of the bushing surfaces before assembly.  I also put the two clutch packs together this time on the input shaft first..making sure i felt the four clicks and the bottoming out solid click.   Then lowered in the entire assembly and rotating it got four drops and could feel it bottoming out.  I "think" both are fully engaged.   

Next i took off the pump outer seal and left out the pump gasket and the front band, and dropped the pump into "postion" but didn't tighten any of the bolts to seat it.   So the pump was in enough to hold the shaft but not seated.  I did all this with the transmission in the vertical position.   I then put a large straight edge across the bell and measured with a digital ruler the distance from the end of the input shaft to the top of my straight edge.   2.655 Inches. 

Next i laid the transmission back onto my table to check for endplay.   It was there but to get the input shaft to move, I had to grip it with a pair of pliers to pull it out.   It moved but it took a good deal of force.   Then using my digital ruler measured placed it to the end of the input shaft with its extension down to the lower shaft and reset the digital ruler to zero.   Then tried pushing in the shaft but it wouldn't move, so tapped it with the rubber hammer and it moved.  Remeasured and had .068 difference...   so that is the end play and falls within the .030-.090 range the book says is good.   Tapped it back in with my rubber hammer.  Then again using pliers pulled it out and remeasured after tapping it in with rubber hammer..  still showed about .068. 

Moved the transmission back to vertical and remeasured with a straight edge...still 2.655 inches.     Pulled the pump back out and remeasured again..  Still 2.655 inches so the input shaft is still I think fulled seated.  Put in my front band, outer seal onto the pump, and the pump housing gasket and put the pump back in and this time all the bolts and torqued to spec 150 inch lbs.   Remeasured with my straight edge and this time have 2.657 inches, so basically the same...   I guess the housing gasket makes up the slight variation.   

Back onto the table, and now i cant get the input shaft to pull out even with a pair of pliers.   To rotate the input shaft I have to put a pair of pliers onto it to turn it.  It will not turn by hand.

I am thinking that the three new bushings, are simply that tight and that i'm ok.   Or is this stupid wishful thinking??   Has anyone encountered new bushings that are that tight as to prevent shaft movement by hand?? 

[1 Wild R/T]

Definitely sounds like the bushings are your issue but & don't think I would just say it's ok.... The bushing collapsed slightly & will cause problems....  Did you have a shop drive the bushings or did you do them yourself?  I've seen posts suggesting they can be driven with a wood block or a socket... Neither is correct, sometimes you can get away with it but the tool should support it inner ID while the bushing is driven....

[chargerdon]

Took pump back out and examined the input shaft on the pump, and the problem is definitely the bushing on the back side of the pump.   I believe it is called the "stator" bushing part 12037.   I believe for that bushing we did have a bushing driver tool while for the other larger ones we used a block of wood.     

At any rate it is too tight.  Feeling it with my finger i couldn't tell anything and its down in there 1.4 inches from the pump end so cant really see anything.   It is in straight as i used a digital ruler and was able to get readings on four sides to all read 1.40 to 1.41 inches from the outer edge.  So not cocked.   

I tried using 240 grit emery paper on it and it will loosen it up..  I'm sure that if i sanded enough I can get it loose enough to work and then polish with 500 grit paper.  Is this acceptable, or must i try replacing that bushing again??   I plan to put about 1-2000 miles a year on it, so it doesn't have to last 100,000 miles.   

thanks

[chargerdon]

I was able to use 240 grit paper on the stator bushing, and then final polishing with 500 grit, and it all fits well now, and I have .047 end play.  So going to put her all back together and put in the car.

Here is another problem, in rebuilding the 904 I ran into a lot of differences from the manual.   Turns out after searching the net I was able to determine that the 904 is NOT a 74, but instead is an "early 68".   Using a shop manual for my 66 Charger, it explained away all of the variations that I came up against. 

Here is one I havent resolved.   The 74 Challenger expects the tranny neutral switch to also be the reverse light switch.   However, back in 68 the reverse light switch was on the floor shifter not the tranny.   Putting in the combo switch, it looks like the shifter has a differently made switch fork on the valve body, and it will activate the reverse portion not only in reverse, but also in drive.   Anybody know how to correct this??    Anybody have an 71 up old Valve Body shifter??  Seems this is a part not sold separately.    Or know how to modify the 68 one?

[1 Wild R/T]

First your bushing is probably fine..
Second, sorry a 68 valve body won't work your back up lights.... , well you could change the comb/selector but bolting in a 69 or later valve body... Best option 71 & up had part throttle downshift..

[chargerdon]

When searching for valve body, 904 and 727 the same...??  ?? so should look for 71-76 either 904 or 727 ?  Or only 904 ?

[1 Wild R/T]

They interchange as an assembly..

[chargerdon]

Was able to find a used valve body from WIT ...listed as Non-lockup...72-86   That has the correct rooster comb on it for only $38..after "mechanics" discount.   
See: U12740 https://www.wittrans.com/parts?type=A904%20(30RH-32RH)&section=90_case&part=740

It appears that this has the part throttle kickdown mechanism on it...   

1a) Now debating with myself whether to take off the rooster comb and put it onto my original 68 valve body which I had already put a Transgo shift kit into it...     

1b) also move the part that I think governs part throttle kickdown to my 68 VB

or

2) Take the parts for Transgo out of my 68, and apply to the newer VB, and install it.   

HMMMM 

Suggestions ??

2) Also remove the "back part"

 Remove the shift kit parts from my original 68 valve body and put them into the one I got from

[1 Wild R/T]

Either option works..

[chargerdon]

After examining fully the used VB I bought, decided to move the rooster comb to my older VB.   

Reason being, it appears that the used VB has been "messed with".

A couple of the cover plates are wrong, which prevents it from going down into 1st gear position.  Also, someone ground off the "lug" on the side of the housing where the spring/ball for the ratchet are, which allows the Rooster comb to move a little to far in park, allowing the throttle valve to go out a little to far, and it can get hung up.   This could cause the transmission to get "stuck" in park.   Don't need that.

ALso, I tried to move the part throttle shift parts to my 68 VB but, the two rods inside have a larger diameter than on my 68.   Since the rooster comb did fit fine on my 68, I moved just that and put back in my 68 with the Transgo kit installed. 

Now to get the transmission back onto the engine.    Its a TIGHT FIT...   between my header pipes, and the transmission tunnel...   Amazing anyone can get an A518 into there!! 

Will let you know how she runs once its back in. 

Thanks again

[chargerdon]

Success !!    Got it back in the car...  and everything hooked up and took it for her first test drive.    Yeah !!    I got all gears, and she ran very smooth!!  Not happy with the shifting, still very soft on the shifts, but, it ran good and strong.   

I DID IT !!!   Now will see how it holds up!!

Next step, is to swap out the 2.76 open diff, with a 3.23 suregrip I picked up!!   Should make her come alive and still be very streetable !! 

Thanks for the guidance and support !!