Is it actually the tranny?

[RetroJohnny]

Hey everyone, I'm back again with yet another question, i love that this forum has so much lucrative information and educated people. Without ya, I would be scratching my head quite a bit.. But anyways, I posted about a month ago that I think my transmission is failing, while it most likely isn't in perfect shape, I suspect my issue is stemming elsewhere. So after a cold start the car shifts very smoothy and no hesitation, but once it heats up to temp (192 F for me) each shift becomes somewhat of a rollercoaster. I cannot give it full throttle much anymore cause it seems to just get confused and end lagging extremely to the next gear. Especially O/D at what seems at about 70mph I get the worst jolt ever, and it comes outta nowhere. I was thinking could this be coming from something electronic? or maybe a coil pack? (which does seem to have that infamous goopy stuff residing around it from time to time) Or heck maybe an ignition module?. I have heard that many other things besides a laggy tranny cause lazy shifting. And no tranny leak either, checked fluid and its bright red and full to the line. And my final point, I just don't have the money for a tranny rebuild, so I'm crossing my fingers it is something less than a GRAND outta pocket. Any other places that are known to cause this type of thing? And what could I replace to just see if it works? OH and if it matters, my highway MPG used to vary between 21-22, now I really can't get it above 19 MPG. Thank you everyone for any help or comments you have!

-John

[2seater]

If there is any doubt about the ignition module, it should replaced. There should be firm and solid potting material inside the ICM. If soft or actually oozing out, it is on borrowed time. There can be other issues of course, but once the ignition is eliminated, we can work on that. The O2 sensor has a large Impact on fuel mileage but much of that may clear up if the ignition is up to snuff.

[89RedDarkGrey]

Upgrade to THIS

[DS_Porter 89 Burgandy]

You may have more than one issue here. That highway mileage is much lower than it should be. I get about 27 highway and about 17-18 in town.

I have been having some shifting issues lately and so I changed the transmission shift modulator. Easy to change, under $20 and mine shifts smoother now.

[RetroJohnny]

17 hours ago, 2seater said:

If there is any doubt about the ignition module, it should replaced. There should be firm and solid potting material inside the ICM. If soft or actually oozing out, it is on borrowed time. There can be other issues of course, but once the ignition is eliminated, we can work on that. The O2 sensor has a large Impact on fuel mileage but much of that may clear up if the ignition is up to snuff.

Thank you, That and the Coil pack is the first to do on my list then.

[RetroJohnny]

9 hours ago, 89RedDarkGrey said:

Upgrade to THIS

Very interesting, the new Delco unit is the exact product on my 98 LeSabre, so that would interchange with little to no modification. Thank you!!!!

[SCOTT's 90's]

23 minutes ago, RetroJohnny said:

Very interesting, the new Delco unit is the exact product on my 98 LeSabre, so that would interchange with little to no modification. Thank you!!!!

 

Best thing about that is you don't have to spend any money to do a test to see if that is the cause of your issues.