Hard shift first to second - low throttle /cold

[JohnKay]

My 99 SHO shift seems to hang up between 1st and 2nd especially when cold and at low throttle. When hot and you hammer it it shifts fine...if I back out though it drops in hard. Recently had the fluid changed out and Mobil 1 ATF and new filter added. Wondering if the shift issue is common or something that I can live with or should I be building a tranny fund quick! Car has 114K on the meter....original trans - not abused.

Any thoughts are welcome.

John

 

[93rev2sev]

Build a tranny fund. I could tell you that without reading but the last part of your post.

In addition, you might try a transmission ("turbine shaft") speed sensor...and find someone to run the codes for you.

 

[JohnKay]

Wow - Intriquing

Build a tranny fund. I could tell you that without reading but the last part of your post.

In addition, you might try a transmission ("turbine shaft") speed sensor...and find someone to run the codes for you.

Thanks for the quick response....not what I was hoping to hear but not unexpected. I trust that your assessment was the result of the miles on the tranny more than the symptoms....given the reliability of the AX4N quite a reasonable assumption. Ideally if I can get 6 months out of it that would be great ...enough time to build the tranny fund and enough time for my wife to forget what I've already put into the cam weld etc. Can you give me more insight into "transmission turbine shaft speed sensor and some one to run the codes for me" Are you thinking there may be some stored OBD2 transmission codes that might help me figure out the root cause of the hard shifts between 1 and 2? Or is there a way to optimize the shifts so that you take into account whatever wear may be affecting the synchronizing and release/engagement of the clutches/bands etc? As you can tell I'm no auto trans expert.

If running the codes means connecting a scanner and looking for faults ....I have an Equus 3160 Code Scan/reader and can run it to trigger and capture live data. Alternately if running the codes is configuring the shifts ...are you aware of anyone on the forum who has done this with success?

Many thanks,

John

 

[Daedalus]

Hi John,

Although the AX4N gets maligned quite a bit, mine has 144k miles on it and it's still going strong. I do have the hard, banging 1-2 shift at low throttle when the transmission is cold and the ambient temps are ~50F or lower. I found that if I'm careful with my throttle modulation, I can pretty much eliminate it.

I am not getting any OBDII codes. If your "SES" (Service Engine Soon) light isn't on or flashing then I doubt that you'll have any codes either. There's a list of the codes somewhere on v8sho.com I think.

I just had a custom tune done by Paul (SHOZ123). He tweaked the transmission shift points, pressures, etc all around, and it actually completely eliminated this issue, in addition to vastly improving the overall quality of all the shifts. Something to consider if you're interested in that sort of thing.

 

[JohnKay]

Hi John,

Although the AX4N gets maligned quite a bit, mine has 144k miles on it and it's still going strong. I do have the hard, banging 1-2 shift at low throttle when the transmission is cold and the ambient temps are ~50F or lower. I found that if I'm careful with my throttle modulation, I can pretty much eliminate it.

I am not getting any OBDII codes. If your "SES" (Service Engine Soon) light isn't on or flashing then I doubt that you'll have any codes either. There's a list of the codes somewhere on v8sho.com I think.

I just had a custom tune done by Paul (SHOZ123). He tweaked the transmission shift points, pressures, etc all around, and it actually completely eliminated this issue, in addition to vastly improving the overall quality of all the shifts. Something to consider if you're interested in that sort of thing.

Daedalus - Thanks - that's what I was hoping for.....I agree no codes likely. After the tranny gets warm works like a charm. I'll see if Paul is interested....I sent him a private message a while back but we didn't connect. Think he's just a couple of hours away....if I can improve the shift quality the ride up to see him and the expense would be well worth it...especially if I was able to check out Paul's collection! How long did it take?

John

 

[three50one]

He's just outside Chicago. More then a couple hours away.

If you want to feel his work as far as a tune goes come visit me. He's helped me out with a few issues he really didn't have to involve himself in.

 

[JohnKay]

Youch - Was in Chicago last week when they had the snow and Earth quake.....took me two hours to get there ...by plane. By Car is closer to 12....Will take you up on your offer once the weather breaks. I was sure there was someone who was a SHO tuner somewhere in northern PA - North of Harrisburg if memory serves me right.

John

 

[three50one]

Haven't heard of them. Don't make it up your way too often either way.

I've got a dragstrip down here we could visit if you wish.

 

[stephen newberg]

Although the AX4N gets maligned quite a bit, mine has 144k miles on it and it's still going strong.

I have felt for some time the complaints about the AX4N were a bit overdone. All automatic transmissions need work eventually, its just the nature of the beast when there are moving parts, and lots of them, involved.

Like yours, mine has been fine. I am at about 190K and so far zero problems. Works like a champ.

pax, smn