Loses drive but then okay

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1. Fluid level okay while running, warm, level surface. Yes
1a. Fluid color and smell, just serviced, the shop said it seemed fine, no burning
2. Speedometer reading correctly Yes
3. Shifting normal/hard Normal
4. Shifting into OD okay? Yes
5. Any service engine light: yes/no Sevice engine light when it occurs
6. If SES light on, what codes do you have? Crankcase sensor
7. Model year:Sierra 3500 96
8. Describe symptoms: it looses drive, this has happened while towing and not towing, , the RPM do not seem to increase, it is only tempory, it pulls fine and changes fine normally,
9. Does the engine come up to full temperature? Yes
10. Any service work recently done that may contribute to your issues. NO
11. Does the TCC lock up (or how many "shifts" do you hear?) No
12. Are you experiencing any kind of slipping?
13. What type of rear do you have? (Check RPO codes) 4.10/ 3.73/ 3.42 or 3.08 Not sure, I will find out
14. If you have an accurate tachometer, what is the RPM at 55 or 65? 1750

 

I just had my trans rebuilt picked up Friday, this happen only in drive? has you forced to 3rd, possibly TCC lock in converter is on way out, how's it do on hard uphill pull or kick down hard to pass.

Any issues going from R to D does it hesitate,

 

1996 2500 5.6 with a 4l80e, sometimes it sifts hard & fast 1234 and sometimes it skips from 1st to 3rd but the real crappy part is it takes FOREVER for it to drop into R but when it does it hits hard- but still not slipping in any gear once it's in. what the heck?

 

when was last filter change

what are the codes you getting, that woud be big help

being 3500 most likey it 4:10 rear end

1750 seems low for 55 or 65 mph

 

Not sure about the last felter & lube job, just bought the truck 3 weeks ago. but the code it's shoing is

code "82" Shift solenoid 1-2 Circuit fault. & code "83" TCC solenoid circuit fault.

I have checked the plug it's clean and seems to look ok, all the pins are in good shape. Start it up in the morning and 1234 are ok but it comes and goes. R will sometimes work rite away and sometimes can take up to 20 sec. but it hits nice & hard when it does, no slip. if i had to guess i'd saay the trans had never been messed with & it's got 245,000 on it.

 

i would pull the pan and change filter that way you can see any paces of junk in bottom of pan