93 Q45 transmission/speedometer weirdness

[Lazn]

Recently the transmission in my 93 Q has been acting a little strange, the shifts are still firm, and it is not slipping at all, but it sometimes can't seem to decide when to shift. (sometimes at too Low a RPM, other times at too High a RPM, but not properly corrolated to amount of throttle input) Normally it ****s ok, but the times it doesn't is worrying.

I have had the car for close to 2 years now, and till now it has been shifting great.

I don't know if it is related, but ever sence I got it, occasionally when it is very cold out, the speedometer will show that I am going 90-100 mph when I am actually only going 55-60 mph. This only occures when it is very cold out, and as I am in Phoenix, this dosn't happen often.

Thanks any help, and NICO forums are awesome.

==>Lazn

[maxnix]

I have to ask, what is your flush and fluid replacement history?

May be different problems with different causes. Q45tech has posted about speedometer functioning, so you may want to search on that word in the General and this forums.

[elwesso]

Do you have a FSM= factory service manual.. Some come wiht them already in the trunk... Check there...

Youll wanna do the transmission diagnosis... Here is what you do.. Put the car in drive (engine not running), then turn the ignition off... Turn the trip reset thing counterclockwise, and while holding it turn on the ignition.... IT should then display AT CHECK on the display.. Then, move the shifter to 3, and press and release the accelerator fully.... move it to 2, and then to 1, and then press the accelerator down all the way and release it (when its in the 1 position)... Give it a minute, and if theres a problem with the electronics, it will show up on there... Tell us what the codes are and I can look them up in the FSM... If everything is fine, it wil display OK...

[Lazn]

maxnix: When I first got it, I had the transmission flushed and filter replaced. It has driven for 2 years on the current fluid. (about 20k miles)

elwesso: will do tonight, thanks.

==>Lazn

[nuQ]

does it seem to happen when doing a gradual exceleration, in the 20 to 40mph range, then stomping on the gas, and no downshift. this sometimes happens w/ mine and this has been discussed here before. my transmission is also showing no other signs of problems and had a flush/filter change less than a year ago.jeff

[Lazn]

does it seem to happen when doing a gradual exceleration, in the 20 to 40mph range, then stomping on the gas, and no downshift. this sometimes happens w/ mine and this has been discussed here before. my transmission is also showing no other signs of problems and had a flush/filter change less than a year ago.jeff

It has always done that, and that never botherd me.

This is more severe, eg I will let off the gas and it will downshift to 2nd or 3rd quickly slowing the car.

Or I will not have much throttle at all and it will rev way up to 4k rpms before shifting.

Or it will shift at 1.5k rpms no matter how hard you are on the throttle.

very strange, and only occasionally, it normally shifts fine.

I think it is a connection to the TPS, MAF, or speed sensor. (I hope not the last as my understanding is that is deep in the transmission)

If I put it in 1st, and move the lever up through the gears when I want it to shift, it will work fine, even if it is acting weird in D

==>Lazn

[elwesso]

DO the diagnostic i said above and we can determine what it really is... You sound like your on the right track though.!

[Lazn]

Well I did the diagnostics, and it came back "OK" But also today it shifted fine all day. I guess the next thing to do is to run it again the next time it acts weird.

==>Lazn

[Q451990]

Are the speedometer problems and the shifting problems happening at the same time, every time? I'm not sure if the TCU uses a speedometer input, but I believe it does.

Heath

[Lazn]

Are the speedometer problems and the shifting problems happening at the same time, every time? I'm not sure if the TCU uses a speedometer input, but I believe it does.

Heath

It had the speedometer problems long before the transmission started acting up. That is why I am not sure if they are related.

But of course it has been acting fine since posting here, so I have been unable to redo the test. (niether problem showing itself)

==>Lazn