ENGINE PROBLEM ON CRUISE, OR WHAT?

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quadruplex

Junior Member
Joined
Feb 15, 2020
Posts
2
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Location
Bruce Fla
Ram Year
2008
Engine
3.7
NOT SURE WHERE TO POST THIS BUT, WHEN 2008 RAM,3.7 AUTO IS IN CRUISE CONTROL, IT WILL NOT MAINTAIN SPEED. AT 65 MPH @ 1500 R.P.M.S, ENGINE WILL DROP DOWN TO 60, BEGIN TO SURGE THEN DROP 2 GEARS, EVEN ON MILD GRADES. PRESSING ON ACCELERATOR DOES NOT HELP, IT CONTINUES TO DROP R.P.M.S AND DOUBLE DOWN SHIFT. IF I TURN OFF OVERDRIVE, ENGINE GO TO 2000 R.P.M.S @ 65 MPH AND SIT RIGHT THERE ALL DAY PERFECTLY. IN ANY ONES OPINION IS THIS ACTUALLY A ENGINE/TRANSMISSION PROBLEM, OR IS IT SIMPLY TOO SMALL AN ENGINE OPERATING AT THE LOWER LIMITS OF ITS POWER BAND, IN TOO LARGE A VEHICLE ? THERE ARE NO CODES. THANKS
 

Fast69Mopar

Senior Member
Joined
May 10, 2019
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1,997
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Location
Texas
Ram Year
2004
Engine
5.7 HEMI
NOT SURE WHERE TO POST THIS BUT, WHEN 2008 RAM,3.7 AUTO IS IN CRUISE CONTROL, IT WILL NOT MAINTAIN SPEED. AT 65 MPH @ 1500 R.P.M.S, ENGINE WILL DROP DOWN TO 60, BEGIN TO SURGE THEN DROP 2 GEARS, EVEN ON MILD GRADES. PRESSING ON ACCELERATOR DOES NOT HELP, IT CONTINUES TO DROP R.P.M.S AND DOUBLE DOWN SHIFT. IF I TURN OFF OVERDRIVE, ENGINE GO TO 2000 R.P.M.S @ 65 MPH AND SIT RIGHT THERE ALL DAY PERFECTLY. IN ANY ONES OPINION IS THIS ACTUALLY A ENGINE/TRANSMISSION PROBLEM, OR IS IT SIMPLY TOO SMALL AN ENGINE OPERATING AT THE LOWER LIMITS OF ITS POWER BAND, IN TOO LARGE A VEHICLE ? THERE ARE NO CODES. THANKS
This is a pretty typical situation for a 3.7 powered Ram 1500 with a 42RLE transmission. Once in 4th gear, which is a tall 0.69:1 overdriven ratio, this trans only likes flat ground or downhill grades. Once any type of load is put on the engine the TCM likes to downshift to 3rd or even 2nd gear to maintain speed. The 3.7 just doesn't have the guts to maintain speed especially when the speed control is set.
 
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quadruplex

Junior Member
Joined
Feb 15, 2020
Posts
2
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Location
Bruce Fla
Ram Year
2008
Engine
3.7
THANKS FAST, I FELT LIKE THE SMALL ENGINE WAS THE PROBLEM (NO TORQUE AT LOW R.P.M. ) MY WIFE DEARLY LOVES THIS TRUCK BUT, SHE DOES'NT UNDERSTAND WHY IT.S LIKE THIS OR WHY DOES.NT VERY GOOD GAS MILEAGE,(20 MPG) WHICH ABOUT AVERAGE FOR A V-6. SHE IS USED TO THE ECONO BOXES THAT GET 35 ,40 MPG. I.M NOT FOND OF RUNNING ALL THAT TOP END STUFF( CAMS AND TIMING CHAINS) THIS HARD BUT, I.M GOING TO KEEP THE OVERDRIVE TURNED OFF UNLESS WE.RE ON THE INTERSTATE. HANKS AGAIN FOR THE HELP. QUAD
 

Fishstickz

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Jul 20, 2017
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Location
Oklahoma
Ram Year
'06, '16
Engine
3.7, 5.7 Hemi
Lol the 20 MPG can always be worse (Ive been getting 15 with my 3.7 lol)

If you and your wife love the truck and are willing to spend a pretty penny, a differential gear swap would help out a lot. Most of the 3.7s have 3.55 differential gears, upgrading to 3.92 or 4.10s would set your cruising RPM higher and put out a bit more power to get over the inclines without all the downshifts. As someone who deals with the transmission downshifting on every small hill like you, I'm getting a differential swap when I can afford it.

If you're lucky you MIGHT even manage to squeak out an extra MPG along with more power in overdrive. Don't count on that though
 
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