'94 ATX shifting problem when cold.

[nomad_dave]

Hi all, I've been checking around here and finally decided to sign up. This seems to be the best place of all for good, sound SHO information along with a good friendly group. Anyhow, I was wondering if there were any ATX experts out there who might be able to tell me what I need to change in order to fix this problem with my Automatic tranny. When it is cold outside, say below 60 degrees or so, when I drive off and get going through the gears, the torque converter won't lock up as I get above 50 MPH. The car runs about 500 RPMs higher than what it should if the TC did lock up on time. It will finally lock up after about 10-15 minutes of driving. I use to have a Nissan that did the same thing and the mechanic told me that it was a transmission fluid temperature sensor problem and that the torque converter would not lock up fully until the trans fluid was up to temperature. I was suspecting the same thing here but I was told by someone that we don't have one of these temperature sensors and that it was most likely a valve in the valve body. So my question is... What should I be looking at changing? The car has a newly rebuilt tranny (12K miles ago by the previous owner). Other than the car not wanting to lock up the torque converter when its cold it runs fine. I don't have this problem with the outside temperatures are above 60 so other than moving to Phoenix I figured I should fix the problem before winter sets in here in the Northeast.

Many thanks in advance for your help and suggestions.

Dave

 

[shoclown]

the trans does have a temo sensor somewhat it uses a bimetal strip that when it gets hot it bows and opens afluid passage that will let fluid drain to the side pan. I do not think that this would have anything to do with ytour problem. there is a tsb on this condition it is tsb 96-7-13 i tried to cut and paste but could not. if you are unable to find this tsb i can try and e-mail it to you directly

 

[shogen2]

Now i'm not quite sure how temparture will effect this problem but i know the 2 most popular problems with are tranny's acting funny and are tcc not locking up are the VSS(vehicle speed sensor) which will send false signals to the ecu on what speed the car is actually goinf causing shifting problems and poor tcc lock up. You can tell if it's the vss due to eratic shifting/poor tcc lockup and not downshifting or downshifting and wrong times.

And the 2nd problem is alittle clip breaking causing there to be no 4th gear which to some will feel like no overdrive and it's about a dollar for the part and very easy to fix.

Not sure of any of this helps you help but just wondering if the tranny has any other symptoms that will help with finding whats wrong.

Oh and know the tranny was rebuilt not that long ago but more often then not they will not replace the vss during the rebuilt since it is not internal to the tranny.

 

[N3FOL]

Tsb

the trans does have a temo sensor somewhat it uses a bimetal strip that when it gets hot it bows and opens afluid passage that will let fluid drain to the side pan. I do not think that this would have anything to do with ytour problem. there is a tsb on this condition it is tsb 96-7-13 i tried to cut and paste but could not. if you are unable to find this tsb i can try and e-mail it to you directly

I would be really interested on reading that TSB 96-7-13. My 95 SHO does the same thing what nomad_dave had stated. However, it only happens if the temperature is below 40°F. Thanks.

 

[shoclown]

tsb 96-7-13

i have tried to cut paste etc to get it here and have had problems..can it post it here in e-mail forum? or if you send me email info for you i can send it that way.. if you know another way to post link let me know.

 

[N3FOL]

Tsb

Thanks shoclown for checking on this. Earlier today, I was able to google the TSB # and viewed the article regarding the transmission issue. There was nothing mentioned in the article whether dealers are supposed to do the fix or not. I think at this point, the problem has been identified but no quick resolution for owner's yet.

I will keep track on what transpires in the coming future. Regards.

 

[SHO#7]

The car is supposed to work that way. Every automatic SHO has this. Factory programming.

Mike

 

[nomad_dave]

Thanks

Thanks to everyone who replied. Sorry for the delay in getting back to you all. I was sent out to Canada for work this week and I haven't had much time to scour the Internet all week. Anyhow, I'll try a search on the TSB and see it that yields any help. It may be just like SHO#7 says, its in the program. Now if there was an easy way to change the program, that would be a big help. On a side note, I have an F150 and the shifting is horribly 'soft' by the factory so an after market reprogrammer does that trick to firm up shift. Too bad we are not running OBD2 with our cars. It might help matters.

Thanks much for all of the help. Great group here.

Dave

 

[Axianator]

Dave,

As Mike mentioned, the behavior you have described is completely normal.

Also, while it is entirely possible to modify this behavior with the right programming, such changes should only be made after one has considered the underlying purpose behind the original programming. In this case, the calibration engineers adopted a delayed converter lock-up strategy to compensate for the lowered viscosity of conventional ATF at low transmission fluid temperatures while utilizing the slippage of an unlocked converter to generate heat within the unit and bring the transmission fluid to operating temperature.

Without proper consideration for these design decisions, you could adversely effect the durability and/or longevity of various internal transmission components. Always keep this warning in mind before you modify any portion of the factory program.

 

[nomad_dave]

Good points

Well said, there is usually some good reason for what gets done by engineering but its just annoying when I get onto the highway and have to wait for the TC to lockup in the fall/winter/spring. If all I was doing was driving in town then I probably wouldn't notice it. Now if I only had a trans temp gauge that could tell me what the temp was, life would be good. I guess I'll have to wait until Ford brings back a 2010 Taurus SHO.

Thanks.