Transmission does not engage in any position!!!

JohnnyC

JohnnyC

Member
So here's the problem, I was out driving enjoying the Scout on a beautiful wyoming day and my tranny decided it had enough. As I was accelerating the tranny started to feel like it was slipping and then I quit moving, engine revs but trans doesn't move. There were no loud noises it was quite weird.

I was told that this transmission was rebuilt and had a couple hundred miles on it and I put about 300 miles on it. Now the tranny will not move in any position and I can roll the vehicle in all positions except park.

I'm looking for any insight if possible please.
 
The manual only give a few reason why a "no drive in any position" would occur.

1. Low fluid level
2. Oil filter clogged
3. Oil pump problem
4. Valve body leakage
5. Clutches or servos sticking or not operating.

Check your fluid level first (warmed up and in neutral) and then typically the next step with any transmission issue is normally a fluid and filter change with a band adjustment. Then you go from there.

I guess your transfer case wouldn't have slipped in neutral while driving hugh?
 
My fluid levels were good. The guy who I bought it from has been working with me to figure out the problem and from the research we've both been finding is pointing to the torque converter. When I dropped the pan there was some magnetic black sludge type stuff, about a teaspoon full. And 5 or 6 very very fine silver shavings. Is it a common thing that the tc would go out with the symptoms above?
 
A failed torque converter is certainly not a normal occurrence on these units.

But the lack of any movement is a sure sign of that happening in this case.

The debris found in the pan would not normally occur on any 727, but most especially after only several hundred miles. Also, the typical failure modes don't end up in one simply not reacting at all to an internal transmission issue.

I'd pop the converter out and see if you can have a local shop actually "test" it on a machine they May have. If not, then simply replace it.
 
Shifter cable all good?
When I got mine back from ammco They had a pair of vise grips Holding the cable into the detent on the transmission bracket.
They even put bailing wire From the vise grips To the frame in case they popped open.
 
tiny yokum said:
shifter cable all good?
When I got mine back from ammco They had a pair of vise grips Holding the cable into the detent on the transmission bracket.
They even put bailing wire From the vise grips To the frame in case they popped open.
Click to expand...

Aamco - double a...omfg:yikes:
 
Alright, I stopped putting off changing the torque converter, popped the new one in and same symptoms. It doesn't move in any position. So now I'm beginning to think it's my front pump.

I am seriously considering parting out the Scout and cutting my losses. If that's possible.
 
Your frustration is certainly understandable. Is there any labor warranty that could be enforced? It appears that something was serviced or assembled improperly during the recent "rebuild". Its in full failure mode now and will once more have to be pulled and disassembled for inspection. Most if not all the replaced wear parts should remain serviceable. If this Scout is not being relied upon as your daily driver and there's no labor warranty, you can look at this as an opportunity to learn the inner workings of the a727 torqueflite transmission in your spare time.
 
When you replaced the converter, did you visually verify that the "drive tangs" on the oil pump rotor were in fact both still present on the inner gear? It's fairly common that the inner gear fails when a converter is installed because it was not mounted correctly. Those gears are a casting and very strong unless the converter is forced onto the gear without the tangs aligned properly, that fails the gear and nothing will work at all.

Next up, I'd drop the pan again, then drop the valve body out and actuate both clutches and both servos using air pressure adjusted to 40psi.
 
Mr. Mayben, I see light at the end of the tunnel because of your advice about the drive tang's. Both of them sheared right off. My question is the new torque converter has wider tang slots then the older, will this give me problems in the future? Also if the transmission was working great for 400 to 500 miles why would it fail then? I don't want to have the same problem in the future.

Thanks for your help.

Also since I have it all apart what do I need for gaskets and seals and does IHOnly sell gasket and seal kits?
 
Remember this thread??:

http://www.forums.IHPartsAmerica.com/transmission-tech/5136-2-differant-727s.html

I have no idea "why" the pump inner rotor tangs originally failed on your tranny. It May have actually been partially done when it was previously rebuilt before you actually got the rig and then suddenly the other tang broke off.

Don't worry at all about the tangs and the slot in the torque converter not being very close in size, this is a very normal situation and allows quite a bit of room for alignment of the converter when it's installed into the front pump.

Once the converter is actually properly installed over both the splined shaft and the inner rotor of the pump), the face of the converter will be at least 1/2" behind the bellhousing mounting flange/surface. Then the tranny is bolted in place and the converter pulled forward until it contacts the flex plate in it's proper position. In other words, plenty of room for all kinds of alignment!

The oil pump gears are super-strong and made in cast iron. But they must be properly aligned/installed or the material can shear (in the wrong direction) very easily.
 
I have a spare pump should I replace inner rotor or do both the innee and the outee get replaced at the same time. Can I just swap them or are there fitment issues?
 
When I measured my inside tip to outer tip it measured at .011", should I replace the gerotor because it's not within the .05 - .010 specs?
 
If you have a "matched" set of pump gear parts, then I'd use both of 'em. But that is not really important. When I have to do this same thing a few times a year, I normally replace only the inner gear (the damaged part). As for your measurement, I'd go with what you have, the 0.001" difference is not going to be an issue.

When you assemble the pump, use plenty of atf on both sides of both gears and atf poured into the "mesh" also.

There is no "top" or "bottom" to either gear, they can be installed from either direction.
 
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