ATX Shifting Problems

[projectSHO89]

Well, have driven the newly acquired 94 ATX enough to catalog most of the symptoms in the ATX.

Jerry had indicated that the tranny was slipping in OD. I haven't seen that one yet, perhaps that bottle of Lucas tranny fix has had something to with that.

What I am encountering, though, has appeared only after 5-10 minutes of driving (works fine cold).

1) Delayed/Harsh 1st or Reverse engagement.

2) Bang upshift 1-2 frequently when warm. Premature.

Once engaged, the tranny stays engaged in 1st or Rev except the premature upshift when accelerating. Coming to a stop after normal driving usually results in the transmission dropping completely out of gear. A slight rev of the engine, sometimes to 2-3K, will engage 1st or reverse (harshly..)

Any ideas on what, specifically, is causing the problem from those members with expertise in the diagnosis of this tranny will be appreciated. This is my first foray into working with the ATX, so I have a lot to learn about it. It would be my idea, if possible, to make needed repairs in-vehicle rather than the AAMCO method (All Automatics Must Come Out).

There are no KOEO or KOER codes.

Thanks,

Steve

 

[SHO#7]

The lucas may have helped out with some with the application of OD, but that is most likely as good as that will get.

The 1-2 shift that you mention sounds a lot like the common forward clutch piston that gets stress cracks in it, letting pressure bleed off when it should not. Resulting in a 1-2 flare and slam shift. Very common on the AXOD-E / AX4S transmission. The forward and direct piston are so common that they make updated steel parts. Instead of the aluminium used at the factory.

The falling out at a stop is a pressure problem. The norm is that the seal for the pump shaft starts to come out. Letting the pressure go low. When you rev the motor you increase pump flow, making it apply the low/reverse clutches again.

I am sorry to report that it sounds like she is going to have to come out. The good news is that once it is out, there are lots of good upgrades that can be done. Making the car much more enjoyable to drive.

Mike

 

[projectSHO89]

Mike,

Thanks for your input.

Care to suggest shopping lists both for minimal repair and for a complete rebuild? Need to weigh my options about costs. I will probably order parts from someone like bulkparts.com or similar.

Steve

 

[SHO#7]

The right way to repair a transmission is the only way in my opinion. Which is a complete rebuild. The following list is what I recommend.

Start with a master overhaul kit. This kit should include new clutches, gaskets, seals, sealing rings, o-rings, bushings, and filter. You will want to get a reman torque converter. Not one from autozone. ATC makes great converters, and I have heard good things about " the perfect converter company ". A local transmission shop should be able to point you in the right direction. You will want to look closely at all of the hard parts inside the transmission. Things like planetary gears are expensive, but needed if worn. A must replace is the forward clutch piston, and direct piston. If you have a 93, you need to upgrade the **** tubes. They are in the lower pan above the filter. They supply the fluid and are a good reason as to why 93's fail so often. They were made larger in 94.

You will also want to install some type of shift kit. Most people scream Trans-Go. On the AX4S I prefer the Superior Shift Kit, it will give you more of a firm shift than the Trans-Go while still giving you all of the upgrades that are offered with that. And ALWAYS replace the EPC solenoid. Installing the shift kit will ensure that all the valves are nice and smooth in the valve body, the EPC solenoid has an internal valve that will wear out over time. If you are there, you replace it. IMHO I bypass all of the factory transmission cooling system. No more going through the radiator, and no more of the factory external cooler. That is where clutch material and metal are going to hide. Only to come out later when it will damage the new unit. Install a very nice 30k GVW or so external cooler in place of the factory unit, and you will be fine, unless you are going to race it. Then you may need to make some adjustments there. Like a cooler with a fan or two coolers.

That would be my suggestion. I am sure that there is something that I left out. But for the most part, that looks like a pretty complete list.

If you need help throughout this process, let me know. I would be glad to help you. Oh, replace the VSS and MLPS while it is out too. The MLPS is not to bad. But the VSS will most surely fail at the worst time. Making you mad you did not replace it while it was out.

Mike

 

[Jason Bowles]

Sounds like I'm gonna have to do the same thing? I posted a thread a minute ago asking - what's better tranny swap or rebuild? Also whats more cost effective?

 

[projectSHO89]

Covering my options...

I posted in WTB forum, looking for an ATX. ATX WTB

If you have one available, please reply via PM.

Steve

 

[SeanMc]

Mine will do the bang shift only if I let off after pushing it in 1st. It's actually been doing this for 138k miles (now at 163k, my father bought the car with 25k). Yeah, it's probably time for a rebuild, but it's going to have to wait until I can actually have the funds together to do it. I'll shop around here first, and then compare it to the FPS trans to see which is the better deal.