A904 no shift into 2nd or 3rd

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mopower76

mopower76

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Hey guys,
I have a 74 (I think) A904 that I had out of the car and decided to pull it apart to check clutches and bands.
I replaced the front and rear clutch packs carefully and in order, rebuilt the front pump with new gears and added a 2200 converter.
I used a TCI trans kit/shift kit and did the VB myself also and added a 5.0 front band lever and new front band. I used a blocker Rod in the accumulator also
I’ve done this in the past with good results, this time something has happened.
After start up and fluid check warmed up (full) I always run them through the gears and reverse and check again... it only seems to have 1st and R...
I drove it down the road and back and no shifting.
I decided to recheck my front band adjustment and (horrible to do in the car with exhaust!) it seem like it’s right - turn snug then back off 2 full turns -
I thought sure it was something I did in the VB so I swapped it with my known good (Cheeta Shift Kit) from my 70 Challengers 727 with the same results.
I’m waiting on a new deep pan and a reusable Mopar gasket.
I’m not sure I understand how to do a pressure check with a gauge, I just haven’t found anything showing a detailed process. I have a factory service manual for a 69 Charger that may have it but since we moved I have no idea where my manuals are... probably at the bottom of the hell I call a storage unit.
I really hate not having a shop anymore!
The fact that it goes into drive and reverse well really gives me hope it’s an annoying but fairly easy fix without pulling the transmission out.
I have a new reverse servo that I now wish I would have installed while the trans was out. I literally ran out of time waiting on parts. I’m not opposed to pulling the tail shaft off the trans (I guess that’s the only way to service a A904 rear servo. Couldn’t move the rear band apply lever far enough to get it out of the way fully to get it out, it seemed fine so I left it.
This is my first A904, possibly my last.
Everything else has a 727.

I searched around but have not been able to find symptoms like I am experiencing.
BTW - when I swapped the VB there was quite a bit of band material in the bottom of the pan, no metal but a lump of band material. (Hopefully not clutches...)
I know some is kind of normal for new band/clutches, this seemed like more than I was expecting to see.
 
This book has a pretty good section to show pressure testing and the results you should see.

Tom



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Has the trans been "built" before? When you "shift" into the next gear, does it freewheel? If so to all of the above, you may want to drop the valve body to see if a governor plug has been installed. I used a "known" good case to use in a fully automatic situation. It acted as you are describing. It was a case that I formerly had used in a "manual" shift situation. The result was same as yours. Probably completely different situation, just throwing it out there.
 
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408 swinger said:
Has the trans been "built" before? When you "shift" into the next gear, does it freewheel? If so to all of the above, you may want to drop the valve body to see if a governor plug has been installed. I used a "known" good case to use in a fully automatic situation. It acted as you are describing. It was a case that I formerly had used in a "manual" shift situation. The result was same as yours. Probably completely different situation, just throwing it out there.
Click to expand...
Well, it never does shift into the next gear, it acts the same no matter whare you have the shift lever - i.e. 1st 2nd or 3rd (Drive).
To me it looked to have been rebuilt at some time, the clutches looked like new and it was clean inside. Should have left it alone!
 
I plan on checking the rear band again because I noticed when I pushed the brake to stop the wheels in drive or reverse it would kill the engine. I’m pretty sure the front band is probably a little tight as it was so difficult to adjust in the car.
It’s 2 full turns out from “snug” then locked but as I said it was hard to “snug” and be able to tell if I went too tight with the 2.5” pipe right next to it.
The rear band was done out of the car, snug and 2.5 turns out.
Again, swapping the TB’s didn’t change one thing... I was really really hoping it Would.
 
VOETOM said:
This book has a pretty good section to show pressure testing and the results you should see.

Tom



View attachment 1715346267
Click to expand...
Thanks for the tip, I was hoping someone would be able to show the steps so I didn’t have to track a book down. I’ll be ordering that book for sure, just hoping for something I can look at (procedure wise) for this weekend.
 
If you have a V8 904 and it has the double wrap rear band...the correct adjustment is 4 turns out .....the single wrap slant 6 band is 2 turns...
 
both valve bodies could cause the same problem for different reasons. That said, I would suspect a governor valve or kickdown valve stuck or assembled improperly. Are both vbs later model that match up with the case in the area behind the accumulator? Maybe the first vb had the kd spring on the wrong side of the valve, but the second valve body wasn't a match to the case and bled pressure. Check the date code on the second valve body and see if it isn't around late sixties.
 
CudaFactHackJob said:
both valve bodies could cause the same problem for different reasons. That said, I would suspect a governor valve or kickdown valve stuck or assembled improperly. Are both vbs later model that match up with the case in the area behind the accumulator? Maybe the first vb had the kd spring on the wrong side of the valve, but the second valve body wasn't a match to the case and bled pressure. Check the date code on the second valve body and see if it isn't around late sixties.
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The original VB that was in the transmission when I bought the car and I have no reason to believe it didn’t work as it should. I think the second is a 1968, again it’s out of my 70 Challenger and was working fine when it was removed.
Both VB were assembled correctly, I went back through the original just to be sure it was all done correct.
I’m just assuming it’s not in the VB’s and something else is going on.
I’ll re-check the VB in the car now for fitment but it seemed to mount up and looked right.
 
If you had the output shaft out of the tail shaft. You probably broke one of the governor seal rings(steel). Not to pick, I've done it several times myself, way back when I was learning. never forgot that one!
 
70aarcuda said:
If you have a V8 904 and it has the double wrap rear band...the correct adjustment is 4 turns out .....the single wrap slant 6 band is 2 turns...
Click to expand...
That’s different than what I’ve been seeing, of course that’s online rear band adjustment and YouTube.
I am planning on re-adjusting both bands just to check.
Doesn’t it seem like the rear band is too tight rather than too loose? Especially since it stalls out when I stop the rear wheels (pushing the brake pedal)
And if it thinks it’s in low 1 or reverse that should be the rear band right?
 
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Well of course they bolt on fine, otherwise there would never be a problem. The mating surfaces behind the accumulator; just in front of the rear band. A 68 won't usually work on a 74. I'm looking for reasons that don't involve removal of the trans. And I never assume anything was assembled correctly before I ended up with it.
 
'63GT said:
If you had the output shaft out of the tail shaft. You probably broke one of the governor seal rings(steel). Not to pick, I've done it several times myself, way back when I was learning. never forgot that one!
Click to expand...
I did not remove the tail shaft.
 
CudaFactHackJob said:
Well of course they bolt on fine, otherwise there would never be a problem. The mating surfaces behind the accumulator; just in front of the rear band. A 68 won't usually work on a 74. I'm looking for reasons that don't involve removal of the trans. And I never assume anything was assembled correctly before I ended up with it.
Click to expand...
That’s true, I’ll have it apart later and let you know what I find.
Never knew VB’s would be that different, on the bench they look identical aside from the hole I elongated on the 727 VB to bolt on the 904. (On the thin metal separator plate only)
 
And again, I do not want to remove the transmission. I will if I’m forced to but I really need that to be a last resort. I just don’t have the time and Money to pull it and have it rebuilt. It just doesn’t seem like it should need completely rebuilt.
I’ve done this process in the past with great success, of course that was the past!
I really appreciate all of the suggestions and will be looking into every one.
 
"Have" it rebuilt?? You gotta be kidding. It's easier to redo the front drums than to install a shift kit; by FAR. See, I'm not saying a complete disassembly..just the two front drums; where 95% of a 904 problems always are.
 
CudaFactHackJob said:
"Have" it rebuilt?? You gotta be kidding. It's easier to redo the front drums than to install a shift kit; by FAR. See, I'm not saying a complete disassembly..just the two front drums; where 95% of a 904 problems always are.
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I did redo the front and rear drums, that’s part of what I usually do when I have a tranny out of the car -
I even air tested everything as I was going through it out of the car.
 
CudaFactHackJob said:
Well of course they bolt on fine, otherwise there would never be a problem. The mating surfaces behind the accumulator; just in front of the rear band. A 68 won't usually work on a 74. I'm looking for reasons that don't involve removal of the trans. And I never assume anything was assembled correctly before I ended up with it.
Click to expand...
I pulled the VB and compared it to the 74 not a spit of difference I can see in the cases. Where and how they mount are both identical. Even behind the accumulator.
Again, I pulled both apart and see nothing out of place or put in backwards.
I’ll be putting the 74 back into the transmission because I believe I can now remove the VB as a variable.... hopefully.
 
On the bottom 1/2 its on the piece that’s under the accumulator. It’s on the top 1/2 also, just can remember where abouts. Kim
 
So just an update, I removed the valve body and checked the band adjustments and the servos. Again, front band is close and probably a little tight.
No material in pan this time when removed.
Re-installed VB (1970) and used 42RE deep pan with added drain plug along with reusable Mopar gasket.
Filled while running in neutral as always, went from N to D and noticed it shifted into second on its own!!!
WTF???
I finished topping the fluid up and took it out for a run.
It shifted under throttle at 45-50 MPH (not exact) and I didn’t go far enough to see if it would shift into 3RD.

Any new ideas now? VB pressure too high? Band set too tight/loose? Or could this be all in lockdown adjustment?

I did notice the converter (I think) making funny “clicking/clanking” noises after I shut the engine off since I got it together, after this last fluid change there is no noise when I shut it off.
Strange, I was thinking the noise was lifters draining down after I turned it off. I have a video you can hear it clicking before I do a hot re-start.
 
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