We recently put a used transmission in my buddy car (97 C5 vette) that we got from another member on on here that came from a low mileage (30k miles) wrecked 2002 corvette. From what he said teh transmission work great in that car.
What the trans is doing is under hard acceleration it slips bad in first and second gear. We also installed a new yank sy3500 converter in the car. His car previously had a 3400 stall in it and is tuned for the stall but his transmission recently started slipping 3rd to 4th gear which is why we pulled it and swapped to this one. Is there any thing we can look at to figure this out or is it basicly just a bad transmission? I really haven't sen any that slipped first and second its usually the third to forth. I have hp tuners if there is any thing we should check in the tune but you will have to be pretty specific as I just got the software and really don't know that much about it.

Also don't know if there is a difference but the car is a 97 and transmission is from a 2002 is there any difference in that?

 

The SY3500 is a very low STR which will probably feel
kind of "stretchy" compared to higher-STR converters.

In HPTuners scan tool, log the input & output shaft speeds,
Trans Current Gear and TCC Slip RPM.

Export the logs to .csv, and in Excel make yourself new
columns of (InShaft/OutShaft) and ratio(TransCurrentGear),
and one of (In/Out)/ratio. This last should look like 1.000
except right at the shifts. Deviation means fricton slip
(trans issue); hanging tough means it's just perception
of the SY3500 characteristics.

If this is too muddy, attach a log file and I'll try and show
you what I'm talking about.

 

Thanks for the input guys. If any one else has any thing to add please do.

 

Are you sure the trans is full.Do you know the correct procedure on how to fill with no dipstick?

 

Losing the 3-4 clutch pack is common on a stock unit, and even on a lot of built ones that were not done right. What is the condition of the fluid? Do you see clutch/band material? It will be blackish gray in color when you wipe off the stick. If the pan is off, and you see clutch/band material away from the pan magnet covering the bottom of the pan, then then transmission is history. The transmission will then need to be taken out and see what went away.

 

We have a lift so its prett easy. Just pull the plug on the side and add fluid until it come out then start the car and put it in drive and finish filling it until it runs out of the plug hole.

 

If the fluid is good check line pressure if line pressure is good & you have good line rise then i would have to say you have a trans problem.

 

It is starting out in first. It starts to slip as it gets up in the rpm. I didn't personaly see the trans work in another car but the guy I bought it from said it had no problems and he verified mileage on transmission was 30k miles. I was just hope maybe it wasn't a problem with the trans its self. Installed a new cooler and blew out the lines.