2015 GC not shifting on downhill - Jeep Garage - Jeep Forum

Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK2 - > Trouble Shooting/Problems/Service

Reply
 
Thread Tools Display Modes
 
  #1  
Old 03-04-2015, 08:40 AM
New Member
 
Join Date: Mar 2015
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
mlange is on a distinguished road
2015 GC not shifting on downhill

2015 GC Limited 4x2 V6 with about 600 miles. When driving down any moderately steep hill in 3rd or 4th gear, if I take my foot off the brake or gas pedal the RPMs increase fairly significantly but the transmission does not shift. I suspect this is some form of engine brakeing (trying to keep the speed constant) but it feels so odd and unnatural. Pressing the gas pedal will get the tachometer to calm down and the gears to upshift, but then you're speeding up when you don't want to.

Just yesterday I had the flash update TCM and PCM thinking this was a transmission issue. Now, I'm wondering if this type of downhill reaction is intended? No other noticeable transmission shifting issues.

Our prior 2012 GC didn't do this so it is alarming any time it happens.

Any thoughts or solutions?

Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 03-04-2015, 12:23 PM
AAAA's Avatar
Premium Member
My Jeep: 2015 3.6L WK2
 
Join Date: Jan 2011
Location: Upstate NY
Posts: 3,550
Thanks: 233
Thanked 180 Times in 154 Posts
Rep Power: 1545344
AAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond reputeAAAA has a reputation beyond repute
Re: 2015 GC not shifting on downhill

Happened to me when cruise control was on. It was engine braking to pre-set speed. A little scary at first, but normal in this situation.
__________________
Overland: Nokian WR G3 SUV tires, front and t. c. skid plates, Bosch Icon blades, Husky X-Act Contour slush mats, MOPAR cargo mat. Successor to trouble-free 2011 Limited.
(Avatar- http://www.ussslater.org/)
Reply With Quote
  #3  
Old 03-04-2015, 03:24 PM
Member
 
Join Date: Feb 2013
Location: Southeast PA.
Posts: 190
Thanks: 0
Thanked 8 Times in 8 Posts
Rep Power: 1773
Dave in Pa is on a distinguished road
Re: 2015 GC not shifting on downhill

Quote:
Originally Posted by mlange View Post
2015 GC Limited 4x2 V6 with about 600 miles. When driving down any moderately steep hill in 3rd or 4th gear, if I take my foot off the brake or gas pedal the RPMs increase fairly significantly but the transmission does not shift. I suspect this is some form of engine brakeing (trying to keep the speed constant) but it feels so odd and unnatural. Pressing the gas pedal will get the tachometer to calm down and the gears to upshift, but then you're speeding up when you don't want to.

Just yesterday I had the flash update TCM and PCM thinking this was a transmission issue. Now, I'm wondering if this type of downhill reaction is intended? No other noticeable transmission shifting issues.

Our prior 2012 GC didn't do this so it is alarming any time it happens.

Any thoughts or solutions?
Others more knowledgeable will chime in but after 28,000 on my 2014 here is my take: Jeep has this 8 speed set up to do what you describe, it won't stay in 7th or 8th gear going down a hill if your speed decreases (if you brake etc.) it will downshift and give you "assistance" in slowing down or holding the lower speed. I have gotten used to it and don't notice it bugging me as much now but I still would not choose it. To me brakes are cheap to replace as opposed to a transmission that is always downshifting, I also think it may have something to do with Jeep engineers not wanting it in 7 or 8th as you have slowed to 30 or 20 mph and then asking for quick accerleration so it has to go immediately from 8th to 2nd or 3rd? Not sure. I tow a 21 foot boat in good weather, close to 4000lbs, and the 8 speed & the V-6 do a great job with it, very pleased! dave
__________________
2014 Limited V-6 Tow Pkg 8.4 Cashmere & Light Frost
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 03-05-2015, 12:26 AM
Member
My Jeep: 2015 3.0L WK2
 
Join Date: Jan 2015
Location: Southern California
Posts: 47
Thanks: 3
Thanked 17 Times in 14 Posts
Rep Power: 15243
furbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond reputefurbucket has a reputation beyond repute
Re: 2015 GC not shifting on downhill

It's "engine braking" on purpose- many new cars do it. Just pretend you're driving a stick and downshifting to save your brakes... If it really bothers you you can use the paddle shifters to pick a different gear...
Reply With Quote
  #5  
Old 03-05-2015, 01:16 AM
Member
My Jeep: 2014 3.0L WK2
 
Join Date: Aug 2013
Location: PERTH West Australia
Posts: 114
Thanks: 20
Thanked 7 Times in 7 Posts
Rep Power: 1536
Gustlock is on a distinguished road
Re: 2015 GC not shifting on downhill

Quote:
Originally Posted by Dave in Pa View Post
Others more knowledgeable will chime in but after 28,000 on my 2014 here is my take: Jeep has this 8 speed set up to do what you describe, it won't stay in 7th or 8th gear going down a hill if your speed decreases (if you brake etc.) it will downshift and give you "assistance" in slowing down or holding the lower speed. I have gotten used to it and don't notice it bugging me as much now but I still would not choose it. To me brakes are cheap to replace as opposed to a transmission that is always downshifting, I also think it may have something to do with Jeep engineers not wanting it in 7 or 8th as you have slowed to 30 or 20 mph and then asking for quick accerleration so it has to go immediately from 8th to 2nd or 3rd? Not sure. I tow a 21 foot boat in good weather, close to 4000lbs, and the 8 speed & the V-6 do a great job with it, very pleased! dave
Well said Dave. I have a diesel 14 and tow a 2.7 ton van and find the downshift is also unusual but feel the transmission braking assistance helpful on downhill runs as the engine cannot throttle of enough for maintaining the vehicle speed on it's own to be effective.
Reply With Quote
  #6  
Old 03-05-2015, 10:20 AM
Member
My Jeep: 2014 5.7L WK2
 
Join Date: Jul 2013
Location: Beech Mountain, NC
Posts: 525
Thanks: 19
Thanked 70 Times in 51 Posts
Rep Power: 7202
2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute2014RedHemiGC has a reputation beyond repute
Re: 2015 GC not shifting on downhill

Yes it's normal. The transmission is programmed to hold the gear rather than upshift with no throttle going downhill.
__________________
2014 Jeep GC Limited 4X4 V8 QD2
2012 Cadillac CTS-V Coupe
2011 Chevy Corvette Z06/07
Reply With Quote
Reply

Tags
2015

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
2015 GJ Limited slipping into paddle shifting NancyP Grand Cherokee - WK 2 02-17-2015 08:41 AM
2012 Jeep SRT8 - Loud clicking noise when going downhill bilkster4673 Trouble Shooting/Problems/Service 5 07-28-2014 06:23 PM
transmission not up-shifting while driving downhill justice37 Trouble Shooting/Problems/Service 2 11-01-2013 11:45 PM
2014 Transmission not Shifting gottubes Trouble Shooting/Problems/Service 15 04-30-2013 07:46 PM
New 2012 WK2 Pentastar 3.6 - Downhill Whine Sigma Engine Performance/Intakes/Exhausts 15 12-09-2012 08:17 PM

» Premium Vendor Showcase
Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 07:04 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by FCA US LLC. Chrysler, Dodge, Jeep, Ram, Mopar and SRT are registered trademarks of FCA US LLC.