At freeway speeds the tach is jumping 200 RPM's

Tiny
CALEBERICKSON
  • MEMBER
  • 2000 CHEVROLET BLAZER
  • 160,000 MILES
I have a 2000 Chevy blazer and when I get to around 60-75 mph the rpms start to jump 200 rpm. Could this be a transmission problem? Happens at 60-75 mph
Sunday, December 11th, 2011 AT 5:51 AM

12 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
Most likely not. If the check engine light has come on, have the computer scanned for trouble codes. A bad trans will slip at any speed. My guess is there may be a bad throttle position sensor or something like that.
Was this
answer
helpful?
Yes
No
+1
Sunday, December 11th, 2011 AT 5:55 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
I have p1870 transmission component slipping code showing. Doesn't slip bad though. I was reading up and some were saying possibly torque converter acting up locking and unlocking. I was also thinking of a throttle position sensor going out
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:01 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
200 RPM's would be hard to notice if it wasn't slipping. WHen the RPM's increase, do you feel the vehicle accellerate at all?
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:10 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
Yes when it jumps up and down it will***** a bit. Gets very frustrating driving on highway
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:16 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
Pull forward and back
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:25 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
That leads me to believe the trans isn't the problem. Try having the computer scanned for trouble codes. Most parts stores will do it for free. I think it may be engine related. Also, check to make sure the trans fluid isn't burnt, low, or really dirty.
Was this
answer
helpful?
Yes
No
+1
Sunday, December 11th, 2011 AT 6:30 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
Only codes present when scanned was the p1870. Transmission component slipping.
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:33 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
IS the trans fluid clean and full?
Was this
answer
helpful?
Yes
No
-1
Sunday, December 11th, 2011 AT 6:45 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
I need to check the fluid. Possibly low. I also have a bad thermostat that im going to fix would that have anything to do with the lurching? Being that the engine is not getting to normal operating temp?
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 6:53 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
No to the temp, but yes to the low ATF.
Was this
answer
helpful?
Yes
No
+1
Sunday, December 11th, 2011 AT 7:03 AM
Tiny
CALEBERICKSON
  • MEMBER
  • 12 POSTS
Ok thanks. So possibly could be due to low tranny fluid and slipping at higher speeds
Was this
answer
helpful?
Yes
No
Sunday, December 11th, 2011 AT 7:09 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
Yes, low fluid can lead to low fluid pressure allowing the clutch pack to not be locked.
Was this
answer
helpful?
Yes
No
+2
Sunday, December 11th, 2011 AT 7:30 AM

Please login or register to post a reply.

Sponsored links