First time posting on a forum but have read extensively. My question today is why wont my trans on a '92 larado with the aw4 and 231 shift out of second, i know that leaves me open to every answer, let me explain. I picked up this jeep cause a guy bought it for the drive train to put into a project but discovered the front axle was on the opposite side for his need. He was sold it under the pretense that it only needed a fuel pump to run and drive (which was correct) to get it to start and drive. After I got it running and discovered that the trans only has P, R, N, with D only giving me 1 and 2. I have tested the TPS and replaced it, unplugged the TCM and attempted to drive it manually only to end up with 1st gear alone along with P,R,N. I have read many forums that are leading me to believe the shift solenoids are my issue (I think), however it has left me with another question. I understand that s1 is on in first and shifts to second with both s1 and s2 on, is it possible that s1 isn't turning off not allowing it to shift past second? Hoping to get this answered before I try to replace the trans.

 

When you disconnected the TCM, trying to drive manually should have given you 1st (1-2), 3rd (3) and 4th (D). A Sol#1 issue will leave you with 4th, 3rd, 3rd, 4th, and a Sol#2 issue 1st, 1st, 4th, 4th. I've not read it before but possibly the solenoid is stuck physically, not electrically in the On position, this would make the trans go 1st, 2nd, 2nd, 1st. I think it'd be worth a pan off inspection, pull the solenoids and see if they look damaged or function correctly in a bench test. They should make an audible click but I can't remember if you can physically see them operate when out. I'm not sure how costly they are for you but for me to get a set isn't worth buying them without diagnosing first.

 

So according to this chart below (disregard the red circles) s1 is on/engaged in P R N and 1st and 2nd by what your saying s1 could be physically stuck? Side note when the TCM is disconnected trying to drive manually I placed it in (1 2) and even at 6k rpm it did not shift into 2nd gear.

 

Wait, ...you are driving it in D, right? Just clarifying....

 

Yes when I'm driving it I place the trans selector in D and it only shifts to 2nd gear. when I unhooked the TCM and tried to shift manually is would never shift out of 1st gear even at close to 6k in first I shifted the selector into 3 and the trans continued to stay in first gear. I am going Sunday to the salvage yard to test and pick up hopefully working solenoids. I've found several videos on YT on how to bench test the solenoids and ohm them to check that they are good. I will swap them out ( Along with filter, fluid, and gasket) Sunday night to see if that fixes my issue. Along with being a good son and servicing my moms envoy. oh the joy of being the mechanic in the family. (lol) If swapping the solenoids fix my issue I will be back to inform the page. Better to try the solenoids than sending the trans off to be refurbished for $1,670 plus tax.