Been reading and searching for answers but haven't found anything that describes what I am experiencing so here goes.

99 Blazer 4.3 and the typical 4L60-E four speed auto tranny.

When I shift into drive and first take off, my tranny whines and though the truck moves it isn't the response you would expect; almost like a slight slip and then a hard shift into 2nd gear. This isn't a real hard thudding shift; but none the less it isn't smooth either. Once this is complete there's no more issues with shifting and running under full power. Truck shifts smoothly there after and once driven a few miles and allowed to warm up there are no other issues. I can shut her down, go into a store or whatever and when I fire her back up there are no repeat issues. It only happens after it has been sitting for awhile or over night.
I have had the system flushed, filter changed and refilled. There were no filings in the pan, and everything looked good when the pan was off. Linkage is adjusted right and fluid is topped off, not under or over filled. Timing does not seem to be off as the truck fires right up instantly when you turn the key to the on position. I don't have a timing light to check if it's spot on but don't think this is the problem. All vac lines have been replaced and nothing there is amiss.
I have no warning lights or stored codes of any kind.
I am baffled and though it really isn't a big issue now, I don't want it to become one.
Anyone experience the same thing or have any ideas as to what may be wrong?

 

hmm 108 views and not one suggestion

 

according to the atsg manual

slipping or rough 1-2 shift could be >

1) valve body
2) 2-4 servo
3) 2nd accumulator
4) 2-4 band
5) oil pump assembly or case


Delay in drive and reverse

1) Torque converter

 

The valve bodies are notorious on these,if I recall there was a factory service advisory at one point regarding this. I don't think you searched hard enough as this topic has been well covered in this forum for years. Take the unit to a good ATRA affiliated shop and let them have at it,you'll probably be out the door for less than $500 and with alot more peace of mind!

 

So are the 1st and 2cnd gear cylinoids

 

Oh contrare, spent lots of time searching and reading before I asked. As I stated, truck WAS serviced at a tranny shop, they found nothing to indicate the "cold" issue I am having. There are no service codes, no indication of an issue .. yet.
Thanks for your reply.

 

Fan clutch

 

I would suggest using this shift kit in your trans I bet you wont have any other issues withit afterwards

TransGo Shift kit review - S-10 Forum

 

"When I shift into drive and first take off, my tranny whines and though the truck moves it isn't the response you would expect"


This would lead me to believe the pump may be having issues. Might perform a line pressuer test when its cold to verify correct pressure, and rule that out.

As the for the shift kit I would not bother with it really.

 

Fan clutch, it feels the same way