Tranny misses shift, starter won’t engage?

[ReneGoFast]

1998 Mazda B4000, 4.0 5 speed Auto trans. 160,000 miles, Pulling out into traffic, medium excelleration: trans shifts 1, 2, 3, Neutral!VROOM! Coasting along I Turn into drive of Gas Station, engine revs with pedal, no change in trans no matter what position i move shift lever, coasting into parking i stop and try to back into parking spot, but no reverse gear, engine sorta suptters and dies. CRAP! I try starter, starter motor “whirrs” but does not engage. Crawl underneath and tap, bang on starter to see if I can get solinod to engage with out any luck....Merry Christmas, I now own a dead truck!!
What are the chances the Starter and Tranny die at the same moment?
Not sure i wanna spend big bucks to R&R the starter, just to find the trans is shot, which will cost more than than the trucks worth. What do you guys Think?

 

[Dirtman]

Loosing all forward and reverse gears at the same exact time AND the starter no longer grabbing at the same time is very suspicious. I've never seen it happen but I'm wondering if somehow the flexplate broke? Id pull the starter and see if the flex plate moves... The engine dying as well is odd.

 

[snoranger]

Sounds like you broke the flex plate. It's not uncommon. They usually have issues around the crank bolts.

 

[RonD]

Yes, +1, flex plate has failed

Need to pull back transmission to replace it so not a small job

Replace Rear Main seal at the same time

This was more common on the 1996 and older 4.0l with 6 bolt crank, 1997 and up 4.0ls OHV or SOHC have 8 bolt crank, but could still happen

If you will DIY this, make sure you know about seating the torque converter inside the transmission BEFORE bolting trans to engine


We often assume people know all these part names and what they do

General diagram here: http://enthusiastnetwork.s3.amazonaws.com/uploads/sites/21/2015/03/early-transmission-swap-diagram.jpg

The Flex plate bolts to the crankshaft of the engine
The flexplate has a Ring Gear around its edge, the starter motor engages this ring gear to turn the engine over

The transmission's torque converter bolts to the outer edge of the flexplate, engine crankshaft RPMs turns the flexplate and then flexplate turns the torque converter at same RPMs

If the flexplate has broken where it bolts to the crank shaft(most common place), then torque converter is not turning, so no trans/vehicle movement
And Starter motor would only be turning flexplate's outer edge and torque converter not the engine

Picture of broken flexplate here: http://jaguar.professional.org/snaps/ford/flexplate_out_2.jpg