Slayer

Okay, hopefully, someobe can shed some light on my problem. I have a 1993 Z28 with a 4L60 transmission, with a B&M shift kit and transmission cooler. Recently, it stopped shifti g properly. Normally, it shifts into second around 10-15 mph, into third around 25 mph, and into fourth around 45 mph. Each time it shifts, I could feel it shift and watch the RPMs drop with each shift. Now, I can barely feel it shift, and the RPMs run up to almost 3,000 before it finally shifts and drops the RPMs to 1,800 at around 50-55 mph. My mechanic replaced the governor to no avail. He consulted with a local transmission guy, and they both think the valve body is just stuck, so they added an additive to the transmission, and I'm going to drive it back and forth to work this week to see how it performs. I don't think the additive is going to fix the problem. When I manually shift the transmission, the RPMs will drop approximately 500 RPMs with each shift, and I can feel the transmission shift and watch the RPMs drop. I've been researching this issue online off and on all day, and I'm more confused than I was because everyone seems to have different advice. From what I could find online, it could be a stuck valve body, a misadjusted cable, a bad clutch pack, or a bad solenoid. Any other ideas?

Fatdog2

Just wondering,are you using synthetic trans fluid?Previous posts from long ago suggest this may too slippery for the 4L60(used to be the 700r4) trans.B&M had special trans fluid for their shift kit but wore out the clutches faster than normal.I'll probably get blasted here and I'm no trans repair guy,but I would check with B&M directly on this.Personally,I use Walmart supertech auto trans fluid Dexron,about $12.00 a gal.Works for me.Hope this helps.
P.S.Has the trans fluid and filter been changed lately?My02.

Slayer

I've had the shift kit since 1999 or 2000, and I know the fluid has been changwd since it was installed, but I can't remember if synthetic fluid was used. After more research last night, I found anotherwebsite that suggests the VSS is bad if the transmission will shift manually but not automatically. I guess I'll look into a new VSS as a starting point.

Injuneer

Where did you find the reference to the VSS causing the non-shift problem?

Just thinking out loud.... VSS feeds the ECM. ECM does not control anything in the trans other than converter lockup. ECM feeds speed signal to speedometer and cruise control module. If the speedometer is working correctly, the VSS is working. Faulty VSS sets DTC 24.

Other than some sort of input to tables for converter lockup, the VSS wouldn't seem to affect shifting, manual vs. automatic. It could be the cause of non-shifting on a 4L60E, but I don't see how it would affect the 4L60. I could be wrong.

Could you link your reference?

Slayer

I researched so many websites that I can't find it now, but I know it's not the VSS because the car isn't throwing any codes. I'm leaning toward a rebuild now.

Ananta1369

Have you recently made any changes or adjustment to the TV cable? If it's out of adjustment it would explain your issue.

http://www.superchevy.com/how-to/651...ting-tv-cable/

Slayer

One of the things I've checked, and it's fine. Waiting on my mechanic and the trans spwcialist to drop my pan and see what they find.