apparently NO TC lock-up
 

Thought I would throw out an interesting 'problem' I recently installed a 'used, low mileage' trans. Adjusted TPS, and did the band adjust, (both, per the GREAT How-to's, thanks!). Also back-flushed the rad cooler while OUT of car.(no new cooler yet). New trans filter inside AND out. Everything is wonderful. Crisp shifts, no flare,(TPS adjustment BTW)BUT!
There is no RPM change EVER in 4th gear, as if it is NOT doing a TC lock-up. No matter throttle position, uphill or downhill. The RPM's don't vary like they should? Help.! I'm stumped.
I went back thru old posts, found miles of discussion about lock-up in 2nd/3rd/4th etc.
Didn't Aredubjey have the same problem a long time ago? Didn't see a resolution to his problem.
Obviously, any help is much appreciated. It is sooo wonderful to not be alone in the wacky world of SVX diagnostics!!
Thanks again, Brian

Just to weed out the obvious...:)

The ATF needs to be at or greater than 150 degrees F, and

The car needs to be above 50mph in 4th, and

You should be at a steady speed, i.e., not under acceleration (or not lots of it anyway - I have no idea how much would prevent lockup), and

then you should see a drop of about 200-300 rpm (at around 50mph) - that is the TC locking up.

BTW, I have an aftermarket cooler and it takes me about 15 miles of driving, in Florida temps, before the fluid warms up enough to get lockup.

Re: apparently NO TC lock-up
 

[QUOTE]Originally posted by mile-hi-bri
[
There is no RPM change EVER in 4th gear, as if it is NOT doing a TC lock-up. No matter throttle position, uphill or downhill. The RPM's don't vary like they should? Help.! I'm stumped.

Brian sorry but what you state is rather confusing.

If the RPM does not change other than as a result of a variation in road speed surely this means that the transmission IS locked up.

Guys, thanks for the replies.
Better info. - When the trans shifts into 4th, (above 50 mph/full temp), the RPM's won't change/decrease/increase at all, like they should. The tach doesn't drop the 'normal' 300 - 500 RPM's, indicating 'lock-up'. Nor does it 'unlock' (increased RPM's), w/ GENTLE acceleration. It just down shifts to third!
ALL shifts are very nice, crisp, no flare, no hesitation, etc. Just no 'lock-up'!
Also, gas mileage is definately down during highway driving! Ideas? Is it possibly a solenoid ... I'm stumped!
Again, thanks so much for the continued help from all the knowledgable folks we have here!

The way I read what you are saying the indications are that fourth i.e. overdrive gear is not in fact being selected. If there is no drop/change in RPM ( I presume from third ) what makes you think the transmission has shifted into fourth ? The poor gas mileage is also significant surely.

Trevor, it does indeed shift in to 4th gear. NO question about that. Just doesn't appear to then do the 'lock-up'(evident by the tach dropping that ADDITIONAL 300-500 RPM's).
Also, when I give it sufficient throttle(but not too much to downshift to 3rd), it doesn't 'unlock' as I remember the 'OLD' one USED to do!
That's why I'm thinking maybe a solenoid...I just don't know this trans. idoisyncrasies.
It doesn't throw a trouble code at all. I've disconnected the battery two nites in a row, hoping that the next day it would save a code when I drove the car and had the same symptom repeat...I'm frustrated.
Thanks for reading and thinking and...
Brian

Brian,

It could be that you are now comparing a tranny which is operating correctly with your old one which was not, but the increase in gas consumption you report. does not relate to this possibility. Your best bet will be to get advice from someone who can test drive the car.

This thread is confusing although it sounds like an issue with the Duty Solenoid B malfunctioning.

RPM's at 60mph are consistantly about 2000 with TC lockup and maybe 2200 without lockup (variable with go-pedal pressure)