2015 8-speed (Hemi) differences - Jeep Garage - Jeep Forum

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Old 12-22-2014, 07:54 PM
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2015 8-speed (Hemi) differences

So...after getting my replacement 2015 WK2 (Hemi) I've noticed some differences with the transmission (8HP70) compared to my 2014.

1) It holds gears longer under moderate throttle -- shifting between 2400 and 3400 RPM (depending on throttle input). Of course it shifts at lower RPM with light throttle but it definitely revs higher than the 2014 did.

2) It doesn't go into 7th unless you're over 45mph. It won't really go into 8th unless you're over 55-60mph.

3) Its much quicker to downshift -- especially going from 8th to 7th on even minor hills.

So...either quite a few things have changed or...my 2014 had a problem or this one does . My kingdom for consistent behavior between similar vehicles

Trans. temp also is a little weirder than my last one. The 2014 basically got up to 194-195F and only went above that with really spirited driving. The 2015 seems to sit around the same range but will quickly climb to 197-201F with only moderate acceleration. It'll hang there for a while then suddenly drop back down. Sometimes at stop lights when it has climbed to 199F as above it'll suddenly drop down to 183-186F in the course of 10-15 seconds. Then the second I accelerate it climbs rapidly back to 195F or so (a few seconds). It's...weird...

Anyone else with a 2015 and Hemi notice these things?

More curiosity at this point than anything else.

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Old 12-22-2014, 09:55 PM
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Re: 2015 8-speed (Hemi) differences

There was a software update available for '14 V8 transmissions to make it behave as you describe for the '15. I love the way mine up shifts quickly returning decent mpg's and great acceleration when you need it.
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Old 12-24-2014, 06:14 PM
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Re: 2015 8-speed (Hemi) differences

Quote:
Originally Posted by 2014RedHemiGC View Post
There was a software update available for '14 V8 transmissions to make it behave as you describe for the '15. I love the way mine up shifts quickly returning decent mpg's and great acceleration when you need it.
I had this update done and it does behave as the op stated on his 15.
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