Won't engage 1st from neutral or park without a bit of revving?
11-10-2009, 09:30 PM
#1
Won't engage 1st from neutral or park without a bit of revving? I put a freshly built 4L60E into my '06 GTO, using a stock TCM with a stock tune. It has a strange issue I've never experienced with any other auto trans.
When I put it into gear, not moving, sometimes it acts like it's still in neutral. If I start revving the engine a bit, it catches, quite hard, like a neutral drop. Sometimes I have to rev it over 1000 RPM. It doesn't do this all the time, maybe 50%. And once it's gone into gear, it doesn't do it again unless I go back into park or neutral first. I wonder if this could be from a sticky valve or solenoid?
There's plenty of fluid and once it's engaged, all seems fine. Seems to shift fine.
Has anyone had this problem? If so, what was the cause?
Just having spent a week swapping to the A4 from an M6, I'm really not looking forward to dropping the trans back out.
When I put it into gear, not moving, sometimes it acts like it's still in neutral. If I start revving the engine a bit, it catches, quite hard, like a neutral drop. Sometimes I have to rev it over 1000 RPM. It doesn't do this all the time, maybe 50%. And once it's gone into gear, it doesn't do it again unless I go back into park or neutral first. I wonder if this could be from a sticky valve or solenoid?
There's plenty of fluid and once it's engaged, all seems fine. Seems to shift fine.
Has anyone had this problem? If so, what was the cause?
Just having spent a week swapping to the A4 from an M6, I'm really not looking forward to dropping the trans back out.
08-31-2011, 01:55 PM
#4
Update When someone posts about an issue, I appreciate when they return to update on what the eventual cure was, so here it goes.
The converter in the trans grenaded some time after my original post, so I installed a 2nd trans, and had this one cleaned out and reassembled as a spare. No seals were found to be nicked or cut, and the VB was in perfect shape (no binding valves). So the delay remained a mystery. The 2nd trans eventually lost 3-4, so this original trans went back in. This time, it would go into gear without a delay, but at WOT, it seemed to oscillate...slipping and grabbing. Very shortly afterwards, the input drum core shattered.
Now this is just speculation, but I think it makes sense.
I believe the original delay going into drive, as well as the oscillation, was due to an already cracked input drum. A crack in the input shaft spline area of the drum could conceivably cause a pressure leak, as well as binding of the pistons in the input drum.
I expect that when I get it back together, both of these symptoms will be history.
The converter in the trans grenaded some time after my original post, so I installed a 2nd trans, and had this one cleaned out and reassembled as a spare. No seals were found to be nicked or cut, and the VB was in perfect shape (no binding valves). So the delay remained a mystery. The 2nd trans eventually lost 3-4, so this original trans went back in. This time, it would go into gear without a delay, but at WOT, it seemed to oscillate...slipping and grabbing. Very shortly afterwards, the input drum core shattered.
Now this is just speculation, but I think it makes sense.
I believe the original delay going into drive, as well as the oscillation, was due to an already cracked input drum. A crack in the input shaft spline area of the drum could conceivably cause a pressure leak, as well as binding of the pistons in the input drum.
I expect that when I get it back together, both of these symptoms will be history.
