2F,4:88,37'
- Thread starter SteadyT3ddy
- Start date
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It would probably be good to let us know what transmission you have and what gear you are using.
If you have a manual transmission, and everything else checks out, I guess your clutch might be slipping.
You can do the calculation your self for any rpm/gear/speed combination. To rule out the clutch you could try it at a low speed to see if it is still not agreeing with the calculation.
If you have a manual transmission, and everything else checks out, I guess your clutch might be slipping.
You can do the calculation your self for any rpm/gear/speed combination. To rule out the clutch you could try it at a low speed to see if it is still not agreeing with the calculation.
- Thread starter
- #23
Have the new 8 speed auto trans from the 2016 LC 
JK- The stock 4speed.
JK- The stock 4speed.
cwwfj60
Supporting Vendor
and you didn't forget to shift to 4th right? lol, so does your truck pull strong up to 3500? maybe it is the clutch slipping, that's the only logical thing at this point
- Thread starter
- #25
No lol.... 65 mph attempt was made in 4th gear. pull strong? I wouldn't say strong... its like a damn john Deere engine. car doesn't move. Of a red light I'm able to get it moving with a lead foot.
That 65MPH chart suggests that RPM with 5.71's or maybe 5.29's. I would definitely spin the shaft and check your ratio. If the d-shaft spins more than 5x for one turn of the wheel you found your problem. Still, I am puzzled that your speedo is not reflecting the speed the truck would think it is going if you are in 4th (1:1) and thus have a drive shaft RPM of 3500 which is around 80MPH. Maybe I misread prior posts?
Frank
Frank
BlueCruiser84
SILVER Star
How does your clutch pedal feel? Engage/disengage at the right level?
If tires are actually 37", and you actually have 4.88 gears, and you were actually going 65, and it was actually at 3500 rpms, and in high gear, and in 4th gear then I think the clutch HAS to be slipping.... I don't think there is any other option...
If tires are actually 37", and you actually have 4.88 gears, and you were actually going 65, and it was actually at 3500 rpms, and in high gear, and in 4th gear then I think the clutch HAS to be slipping.... I don't think there is any other option...
- Thread starter
- #28
Just confirmed. Spun the right rear tire 2x full 360 turns and the D-Shaft spun 4.8 times. Did a clutch test. Had e-brake on gave it a little gas and disengaged the clutch. Car shut right off.. no sign of slippage... Also confirmed vehicle was in 2H. At this point I need all the help I can get.
Some part of the equation is wrong. Either you have 27" tires or your speedo is off (most likely). Is it possible someone changed the speedo gear or that it is simply malfunctioning? Or, the tach is off but by the sounds you described that is probably not it.
To check, did you gps verify speeds?
Frank
To check, did you gps verify speeds?
Frank
LAMBCRUSHER
SILVER Star
my 2F eats 3500 all day long....something does not add up, here...
- Thread starter
- #31
Again... Speeds was verified by phone app. Vehicle does not have 27 tires. im getting a feeling my clutch is slippping at higher rpms
cwwfj60
Supporting Vendor
you should try driving at slow speed and shifting into 3rd or 4th and load up the clutch to see if it will slip. That's the only other thing I can think of, also it may act different after it heats up
Clutches don't slip at high RPM's but at lower rpm's. The clamping force is significantly higher at higher RPM's.
Did they do anything with your transmission when they did the work? How are you verifying that it is in high range?
Did they do anything with your transmission when they did the work? How are you verifying that it is in high range?
- Thread starter
- #37
you or me? I feel like such an idiot about this..
If your clutch aas slipping badly enough to cause this it would be billowing smoke and fail in short order. You might get a Harbor Freight multi meter and read the RPM to verify.
Frank
Frank
- Thread starter
- #39
Aside from the slipping clutch theory, I think you've come to the point where you need to double check certain assumptions like, you tested the speed with your phone GPS, try a different instrument to confirm speed.
