Help with mystery

[swathdiver]

I know. I just measured again today... 2000 rpm was 66mph (on my gps, which I measured as accurate against my other car)

That implies 4.11 gears, but I jacked the back of the car up, chalked one wheel, turned the other twice and counted 3.5 turns of the driveshaft...


So I am really confused!

Did you check your RPO codes? Can you tell via scan tool if your torque converter is locking up and how much slippage there might be? I don't remember that 3.5 turns stuff, just use my homemade Excel calculators.

 

[John Ley]

GT5 4:10 GT4 3:73 GU6 3:42 GU5 3:23 GU4 3:08 GU2 2:73 GU1 2:41

 

[Jonathan V]

GT5 4:10 GT4 3:73 GU6 3:42 GU5 3:23 GU4 3:08 GU2 2:73 GU1 2:41

RPO: GU6, so 3.42 was stock, the 3.5 turns actually measured how many turns the driveshaft (therefore pinion) has to make to turn the wheels 1x (the ring gear). Mine is approximately 3.5 driveshaft turns (therefor 3.42, as .08 of a turn is too small for me to see by hand)

 

[swathdiver]

RPO: GU6, so 3.42 was stock, the 3.5 turns actually measured how many turns the driveshaft (therefore pinion) has to make to turn the wheels 1x (the ring gear). Mine is approximately 3.5 driveshaft turns (therefor 3.42, as .08 of a turn is too small for me to see by hand)

Your tach may be off some and your converter might not be locking up. Are you able to detect whether it is locking up or not? It would seem like another shift and drop the rpms a bit.

 

[Jonathan V]

Your tach may be off some and your converter might not be locking up. Are you able to detect whether it is locking up or not? It would seem like another shift and drop the rpms a bit.

Sorry for the late response, I was out of town. It does seem to lock up, I see a small rpm drop distinct from 4th

But perhaps my tach is wrong, but I don’t have a scanner to see the real RPM

 

[Walkercraig01]

u can grab a elm327 on amazon pretty cheap and get torque or dashcommand for your phone. torque is free tho. can you post a video ?