This is obviously not in my vette; it’s in my 94 full size Blazer.

I rebuilt this tranny about 6 months ago and so far it’s been fine up until a couple weeks ago I developed a problem. When I slow down, like to make a turn into a parking lot, to around 15-20-25 mph and start to slowly accelerate the truck will rev a little like its in neutral, then grab gear. When it grabs its fairly harsh so I don’t think sits slipping and it doesn’t do it all the time. From a hard take off it shifts great with no problems. It has a lot of goodies in it like a Transgo shift kit, drilled Transgo separator plate, Sonnax TCC lock up valve, Sonnax pinless forward, 1-2, 3-4 accumulator pistons, new wider 2nd and 4th band, billet servo, and all new solenoids. It shifts really nice in all gears even 4th gear is firm. I am thinking maybe the regulator valve bore in the pump is worn? The pump was converted to a 13 vane and has the new Transgo boost valve, other than that there was not much done to it just a basic cleaning and rebuild. I have a huge cooler, and an extra deep pan on it. Temps stay around 150 all the time. The fluid looks just as good as it did when I filled it up 6 moths ago.

I plan on hooking up a pressure gage to see if I can see any changes when it happens but just haven't gotten around to it yet.

Any ideas would be appreciated.

 

When it acellerates is it in 1st or 2nd gear. It sounds like it is downshifting to 1st and since it is in OD 1st gear there is no engine braking. The only time I ever seem to experience something like this is when the 2-4 band is burned up and stays in 1st. Maybe you have a shift valve sticking?

 

The gear selector is in OD and I believe the truck is in second gear when it happens. If the band was burnt wouldn't it slip or have a sloppy soft shift? I always have a firm 2nd and 4th shift.