What did I do wrong? FIXED IT!!

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Coyote Jack

Coyote Jack

Member #55, I'm old
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I just finished putting my 727 tranny back in the Demon. It will not go into any forward gear.

Here is what I did. I took the tranny out to replace a noisy pump and front seal. Other than that the tranny worked fine in all gears. When I replaced the front seal I also installed my other converter as the old one had a couple of grooves on the sealing shaft. When I installed the pump I had the front band backed off and I adjusted it to 72 inch pounds then backed it off 2 turns and locked it down. I will say that I just remembered the tranny was in the neutral position when I did this if that makes any difference.

The tranny goes into reverse perfectly and moves the car with no problems, so I don't think it is a converter problem. The tranny makes a whistling noise at all times now that it never made before. The B&M shifter is moving the shifting arm on the tranny properly. The only things I can think of is I adjusted the band wrong or the pump is in the wrong position by 180 degrees. Unlikely but possible, I have seen stranger things.

Anybody got any ideas and how to check for them? Help please!

Jack
 
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Coyote Jack said:
I just finished putting my 727 tranny back in the Demon. It will not go into any forward gear.

Here is what I did. I took the tranny out to replace a noisy pump and front seal. Other than that the tranny worked fine in all gears. When I replaced the front seal I also installed my other converter as the old one had a couple of grooves on the sealing shaft. When I installed the pump I had the front band backed off and I adjusted it to 72 inch pounds then backed it off 2 turns and locked it down. I will say that I just remembered the tranny was in the neutral position when I did this if that makes any difference.

The tranny goes into reverse perfectly and moves the car with no problems, so I don't think it is a converter problem. The tranny makes a whistling noise at all times now that it never made before. The B&M shifter is moving the shifting arm on the tranny properly. The only things I can think of is I adjusted the band wrong or the pump is in the wrong position by 180 degrees. Unlikely but possible, I have seen stranger things.

Anybody got any ideas and how to check for them? Help please!

Jack
Click to expand...
I'm no transmission guy, but I didn't know it was possible to install the front pump upside down. The vent hole goes on the top. Maybe a borescope might tell if it is in position correctly.
 
Did have.the.pump out of the case? You probably fractured I sealing ring on the input shaft during pump installation causing no forward engagement
Good luck Lon
 
The pump will only go in one way due to the bolt holes being oddly spaced. Lkopaska could very well be right. If one of the sealing rings break you'll loose forward. Since that's the only area you were in that'd be my guess too
 
I am just putting this out there, how much trans fluid did you put back in? The converter holds quite a few quarts, although that wouldn't explain why it goes into reverse, but if the trans is pumping aerated fluid, or sucking air because of a low level, that may be an issue. The whistling may be the pump trying to pump air? either way, if you didn't dump 4 or more quarts back into it, Id check that out.
 
Dartswinger70 said:
I am just putting this out there, how much trans fluid did you put back in? The converter holds quite a few quarts, although that wouldn't explain why it goes into reverse, but if the trans is pumping aerated fluid, or sucking air because of a low level, that may be an issue. The whistling may be the pump trying to pump air? either way, if you didn't dump 4 or more quarts back into it, Id check that out.
Click to expand...

I don't think that is the problem. I put 10 liters in.

Thanks for the input though.

Jack
 
did the convertor have ANY fluid in it when you replaced it? I doubt it was empty as they cant dump out 100% due to their design. I believe the max fluid capacity with a empty convertor is 9 quarts ~ 8.5L. A whistle could mean pump aeration (doubtful if you got 10L in there) or a clutch pack pressure issue. I put 5 qts in a C4 once and 2 ended up on the floor, bubbled right out of the vent hole, oops!
 
It doesn't move at all in any forward gear? Doesn't even try to even if you rev it? Did it move a little bit then just stop moving it at all?

I'm thinking maybe converter not seated properly? I know that can cause loss of all forward (and reverse) gears. Weird that reverse works fine though.
 
Since reverse works, it uses the L/R band and the hi-drum so those are working. That means the pump is working. And that means the TC is working, and so at least two cast slip rings are working.
No forward gears could mean the forward clutch is not working, and/or the L/R band in manual low, and/or the rear sprag. But we already know that the L/R band is OK (cuz reverse works) and if the sprag goes, you get no locomotion period.
So the bottom line is that the forward clutch is not working.
If neutral works, with no tendency to creep, then I have to agree with ikopaska, that one seal ring got snagged.
If it was me I would do a hydraulic pressure test, and if the pressure test fails then down comes the tranny.
 
pishta said:
did the convertor have ANY fluid in it when you replaced it? I doubt it was empty as they cant dump out 100% due to their design. I believe the max fluid capacity with a empty convertor is 9 quarts ~ 8.5L. A whistle could mean pump aeration (doubtful if you got 10L in there) or a clutch pack pressure issue. I put 5 qts in a C4 once and 2 ended up on the floor, bubbled right out of the vent hole, oops!
Click to expand...

I have an extra deep pan so yes it can take 10 liters.

Jack
 
Is it possible to install the pump cover on the housing wrong and that effect the engaging of the forward gears?

As far as the rest goes, remember I only took the pump out and adjusted the front band. So any problem should be related to that area.

If the converter is not seated properly I doubt I would be able to spin it after bolting up the tranny to the engine.

Jack
 
I hope you get this fixed easily ..... here's a bump for you Jack
 
Coyote Jack said:
Is it possible to install the pump cover on the housing wrong and that effect the engaging of the forward gears?

As far as the rest goes, remember I only took the pump out and adjusted the front band. So any problem should be related to that area.

If the converter is not seated properly I doubt I would be able to spin it after bolting up the tranny to the engine.

Jack
Click to expand...
When you reinstalled the front pump-house into the tranny, you had to engage at least 3 seal-rings; 2 on the reaction support and 1 on the input shaft. From the factory these are made of cast-iron and come with interlocking ends that are nearly impossible to snag and break. During a past rebuild,these may have been replaced with Teflon split rings, that do not have the interlocks.
These can be very tricky to properly engage.I usually take them over to the anvil, and smash them a few times before throwing them away. Then I put the oem stuff back in,lol. I hate those squirmy Teflon noodles.
 
Did you adjust the fwd band with the pump installed? It needs to be installed when you make this adjustment.

Did you reinstall the paper gasket between the pump housing and trans case?
 
Also check to see if the paper gasket did not slip out of place or installed improperly and cause blockage since you will be pulling the pump again. This happens quite easily and the bolts will thread through the gasket. I usually use a little trans assembly paste to hold it in place while putting the pump in.
 
Moparman1806 said:
Also check to see if the paper gasket did not slip out of place or installed improperly and cause blockage since you will be pulling the pump again. This happens quite easily and the bolts will thread through the gasket. I usually use a little trans assembly paste to hold it in place while putting the pump in.
Click to expand...

I used just enough rtv to hold it in place while I installed the pump.

Jack
 
I took it apart today and checked everything I could think of. Everything looks as it should. No broken or cracked rings. Everything was clocked correctly. Bushings look great. I guess I am in for some heavy reading tonight.

Jack
 
AJ/FormS said:
So no pressure-test results then?
In that case yes, you're in for the long haul, and there is no guarantee that it won't still be slipping after the re-install.
Click to expand...

The odd thing is that the tranny worked perfect before I took the pump out. I looked at the old pump casing today and I was lucky I did this when I did. The front bushing was in really bad shape. I will read tonight and test tomorrow.

Jack
 
Hey Jack
If you replaced the pump, are you Shure you got the correct pump stator support for your trans? There are different stator supports for different years,some have larger ring diamaters or number of sealing rings on shaft and drum. Some use two rings ( 1 large one small) later supports use 3 rings ( one large and 2 small) for lock up style convertors, they won't interchange. Look at inside of support and compare ring areas- test fit rings on shaft in support for correct fit
Lon
 
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