No second gear

[Paul G]

A518 automatic overdrive. I was stopped with the engine idling in gear, heard something make a loud POP noise. After that i had no second gear. The car will start out like normal in first, around 20 mph when it should be shifting to second the rpms rise and i cant go any faster. If i hold it in first it will accel and decel like normal. Cant get third gear. Reverse is normal.

Any ideas?

[John_Kunkel]

2nd gear is a function of the kickdown (front) band, you could try adjusting it but the pop makes me think the band has broken or the lever link popped out....pull the pan and have a look see.

[Paul G]

I pulled the pan. Lots of metal in the pan and on the filter. Not normal metal flake looking metal, more like filings and really small chips of metal. The trans was rebuilt 1 1/2 years ago. The fluid is still red looking but does have a slight burnt smell to it, very slight.

The band you adjust from inside the pan, first gear band? I can pull on the actuator arm and feel when it makes contact, then pull harder and it feels like it is squeezing harder the more I pull on it.

The band you adjust from outside the case of the trans, second gear? I can pull on that actuator arm and it moves easily until it stops moving completely. It doesn't feel like it touches and then squeezes, It just moves to the end of it's travel and that is it. I can see the strut still attached to the arm. I was hoping the strut came off or something. I guess not?

I did not drop the valve body. Any reason to dig further?

[John_Kunkel]

If you can pull down on the front lever and it has some resistance and will pop back up when released, the band and its components are intact. If the lever pulls down more than 1/2" before it stops you can try an adjustment.

If that doesn't fix it there is something amiss in the servo (the piston and plunger that activates the lever), inspect the outside of the servo for any obvious cracks or a dislodged snap ring. In order to properly check the servo operation you need to pull the valve body and apply air pressure to the servo port in the case.

[Paul G]

Pictures of the carnage. The button looking thing in the upper right corner of the pan worries me.

[flyinlow]

Never broke the second gear band on a 518, but when it happen on a 904 you could start in manual low and speed up to about 20-25 ,shift to drive while letting off the gas and the trans would go into third where if you where carefull and accelerated slowly (not kicking down to second) you could drive the car home.

Seeing that button part ,I think its teardown time. Still under Warrentee?

[John_Kunkel]

Is the "button" made of plastic or metal or a combo of both? It might be a part of the valve body governor solenoid or sensor which are both visible without removing the valve body and both of which control the upshifts.

[Paul G]

Took the pan with the debris in it to the guy who built the trans. He thinks that button part is either part of a solenoid or a governor. He wants to tear the trans down and clean it out. He doesn't like the amount of debris that is in the pan and on the filter. He doesn't think the band itself came apart, it was new a year and a half, 4000 miles ago. Wont know for sure till tear down.

Right now I plan to drop the tranny and take it in to him. If it is the governor could that explain why I could not get in to third either?

[Paul G]

Got the trans in to John this week, he rebuilt the A518 for me 1 1/2 years ago. I watched him open it up yesterday. First thing he did was pull the tail section off. I was curious why he was going for the tail section first? He said he suspects the governor and wanted to take a look there first. Sure enough the governor was broken. It has weights in it of some sort, one set of weights was intact, the other set looks like it exploded. John said there are small "c" clips that hold in a pin. He suspects a clip came loose or failed some how and allowed the governor to destroy itself. I did not want to get too much in his way exploring the broken bits. But he said he will just fix it if I pay for parts.

He wants to tear down the rest of the trans to clean out any remaining debris, told me to flush out my cooling system with brake clean several times before it goes back together. He said this trans was designed for ATF3, you could use regular Dexron, but use ATF+4 synthetic. It is a much better fluid.   

Is the governor a part that normally gets rebuilt or replaced during an overhaul?

Is extended first gear use exceptionally hard on the governor? Like in autocrossing?     

[flyinlow]

Glad to hear it sounds like a minor repair. Hopefully he finds no other damage.

I use ATF+4 in mine. Has worked well so far.

In D or 2 the governor is King. It regulates the governor pressure as a function of tailshaft  speed. It works against the throttle pressure in the 1-2 and 2-3 shift valves to determine the shift speed. In manual low the valvebody has nothing to do except port fluid pressure to the rear clutch and low/reverse band. Never heard that it would damage the governor. If I remember right the owners manual said not to exceed 40 MPH in manual low. I assumed that was to protect the engine.