Wondering if anyone may have an answer to this phenomenon...

89 IROC 5.7 / Mild mods... Dynomax Cat-Back, a mild Crane Cam, Gutted MAF, AirFoil, K&N

Tranny acts weird, not sure if previous owner may have done a shift kit or not. Here's what it does:

Hits 2nd gear hard, especially when engine is cold and only low to moderate throttle is applied.

After the car warms up and the throttle is mashed wide open in 2nd, 3rd, or 4th - The tach zings skyward like I'm in neutral.

When I'm in stop and go traffic and the car shifts itself downward into 2nd, (or if I'm putting along in 2nd), and then I come to a near stop and then throttle it again slowly, it will accelerate like it's got a really steep stall converter, (I don't think it does). If I hit the gas more agressively it's not noticeable.

I took it to a mechanic who dropped the pan, inspected and did a fluid and filter service. He told me that the inside of the trans was immaculate and the old fluid was perfectly good.

The car continues to run and drive fine. When heavy throttle is applied while car is in 1st, or in Drive or Overdrive from a stop or slow roll, it pulls great and gets rubber through first, through 2nd and lays a short patch in 3rd.

If I apply moderate throttle until wide open under full load on highway it pulls just fine with no sign of the "slipping" or zinging tachometer I mentioned earlier.

SO.... Anyone have any ideas? I know the 700 tranny is not the greatest, but this is just weird. Is there some kind of computer gadget or vacuum thingamabob that controls the tranny and might be goofy? Does it sound like it may have a poorly installed shift kit? Or perhaps does the tranny just sound like it's weak and needs to be replaced?

 

You're probably looking at a tranny that's trying to fail, but I can't say for sure, as transmissions aren't my strong point. If you lose it, I've got one I'll sell to you with a shift kit and a 2500 RPM stall converter. It's got about 20k on it since I rebuilt it. PM me if you're interested. I'll even include my $30 urethane trans mount with it if you like.

 

The fluid was good because the previous owner did a change. When that was done it removed all the old fluid with clutch material in it. Since that material is gone the trans slips because the clutches are worn. I bet before it was changed the fluid smelled burned and was dark. I am no trans expert but I have seen a lot of this.

 

That's what I was thinking. It would also explain the sudden appearance of those symptoms, as new fluid tends to make old trannies take a dump.