A4LD Won't Engage

[pearsonbe]

This morning after I started the truck and it ran for about 10 minutes, I hopped in and dropped it into D from park. It wouldn't move. So I tried shifting to reverse - still no go. This happened to me once before, so I checked the fluid on the stick knowing it wouldn't be completely accurate since the transmission was still cold; it read full. Ok. I added about between 1/4 and 1/2 quarts but it made little difference. Topping up made a big difference when this happened once before. I did notice a small amount of fluid at the bottom of the transmission pan and the transmission leaks a little when parked downhill. It was rebuilt a year or two ago, has relatively few miles on it, and the converter was new. I know the guy who used to own it.

I read several posts about similar problems and it seems the place to start is a check of the line pressure. Is the transmission "pump" internal or external? I hope it's nothing serious. But I do wonder why a newly rebuilt transmission would leak at all. Not happy.

 

[pearsonbe]

I checked last night and it appears to be leaking between the engine and transmission bell housing. Does this sound like the pump seal is gone? I plan on pulling the transmission to have it repaired. Any advice would be appreciated.

 

[1IronMike]

Sounds like the touque converter went south to me. Good luck.

 

[Glacier991]

A leak there COULD be converter related or more likely is a front seal gone bad. In the Useful Threads there is a thread about how the bushing in the bellhousing really needs to be turned in place and I'll add that some shops neglect to use the proper alignment tool to center the pump in the bushing on reassembly. The result is an unusually high repeat front seal failure rate in these transmissions.

 

[BrooklynBay]

Welcome to this forum! If that pump wasn't aligned properly when they did a rebuild, it could have ruined the bushing, converter hub, and the pump's gears. Check your transmission with a pressure gauge to see if there is any pressure on it. It is also possible that you could have a clogged valve body, or filter. Maybe they didn't adjust the bands properly when it was rebuilt. Try to adjust them. Did you ever drop the pan since it was rebuilt? Check for metal shavings, or any other hard fragments. Sometimes the front cooler could be partially clogged. A good shop is supposed to thoroughly flush it out before reconnecting a rebuilt transmission. As for the front leak in the seal, check your coolant level in the radiator. There is an article on WWW.Atra.Com about this. Here is the link: Dead Link Removed

 

[pearsonbe]

Thanks for the welcome Brooklyn. Since the tranny has to come out anyway to repair the leak, I'm not inclined to spend much time diagnosing the problem. I'll try to find a pressure gauge to get a reading before it comes out. What kind of testing can be done once it has been removed from the vehicle?

The transmission pan looks fine and I have never had it out of the car to drop or driven over anything that may have touched it. I did have heating issues this winter which I resolved and the coolant was full last time I checked. The fluid on the transmission stick also reads full, which means that very little of the fluid has escaped the system. Also, it's bright read on the stick and at the bellhousing and is not burned.

Questions: Glacier991, you said rebuilding the A4 is a DIY job and I'd guess, in terms of difficulty, it's 4-out-of-5 stars. I've never worked on a transmission, but have done about everything else on older vehicles. How long do you expect it would take an amateur to rebuild the transmission? What are the chances of getting it right the first time? Are there any special tools (expensive) required?

 

[Glacier991]

With the tools onsite, and parts available I'd give myself several days of working on it, then reading up on the next step, etc...

 

[pearsonbe]

I had the truck towed to a repair shop where I know a mechanic. IronMike was right, the converter was leaking, so that will get upgraded. The front seal showed a little wear and will get replaced along with a new bellhousing bushing that has been align-bored. After tearing the transmission apart, he saw a couple clutches that were starting to burn and the sun carrier showed a little wear on the exterior. Everything else looked fine, so it will get a soft rebuild and maybe a replacement of the carrier, if not too expensive. When everything goes back together the pump will get aligned also with the proper tool. I'm also going to have him replace the flexplate washer.

He mentioned something strange. When he pulled the pan, there was not a lot of fluid in it, but the stick registered full. I know because I checked it several times and even overfilled it when it wouldn't move.

Hopefully, I'll have it back in a few days.

 

[BrooklynBay]

Your modulator is probably bad. If the diaphragm is bad, fluid will get sucked up from the engine's vacuum. It will be overfilled for a while, but eventually go low. Was there any fluid in the hose when he disconnected it?