auto 518 overdrive prob

[John Martines]

It seems that when in overdrive at any speed if I let off the throttle it will shift out to third and sometimes back in. since it's controlled electrically I'm not sure whitch item to check I replaced the speed sensor last year and i'm not sure if the TPS has anything to do with it. Also when I'm going about 25 mph it will shift in and out of third and second harshly the trans has been rebuilt due to a failed flex plate(it did this before the rebuild also) i;m afraid that the harsh down shifts are going to cause the plate to fail again. Any ideas on the cause?

 

[hdm48]

I'm wondering who rebuilt your transmission? Did they dyno it before it was installed? What your discribing sounds like a line presure issue and posibly a governor. Also has the TPS ever been adjusted? Has the K-D cable ever been adjusted? I would take it back to the transmission shop and have them adjust everything like it should have been done.

Has the valvebody been striped and cleaned and checked for plunger travel? Are the check balls all in good condition?

The shop can do a series of tests to find out what is going on and they should fix it. But you did not say if this is a warranty issue or not.



good luck --dave--

 

[BushWakr - RIP]

Ya, what hdm48 said...

Also the TPS controls the 3-4, 4-3 shift. If it is set incorrectly it will make the shift timing/sensitivity wacky.

If you want to tackle that adjustment, just do a quick search for TPS and you'll get some good posts. . if not, come back in and let us know.



bob.

 

[John Martines]

Well checked line pressure and it's high at idle and low at speed. Also found TPS was low voltage wise. I'll try to ajust it