we have a 20009 chevy tahoe that we take to gatlinburg tenn anyhow when my dad drives he believes in reveing the motor to 4000 rpms in first gear when going down the mountains. i can hear the motor straining under the lower gear he thinks nothing will happen to the motor i believe other wise.yall had an add in todays stae newspaper in south carolina stateing that new cars have a kill switch or they wont reve so high so who is right
4,000 rpm is high but won’t harm the motor, it just makes alot of noise. He must be using engine braking to reduce the load on the brakes. Perhaps using one gear higher would bring the rev’s down closer to 3,200 and still provide engine braking.
If dad’s driving dad gets to make the decision on what is the best way to safely go down the mountain hills. If you are towing a big trailer preserving the brakes makes sense.
Absolutely not harmful to the engine or transmission and the proper way to descend long grades.
The engine is not “straining”. It is simply revving at a high rate.
If the truck has a tachometer, take note of where the engine is “red-lined”. More than likely, it is “red-lined” at ~6,000 RPMs. While 4,000 RPMs does produce a lot of noise, running an engine at ~2,000 RPMs below the red line on the tachometer does no harm if there is sufficient oil of the correct specification in the crankcase.
As the OP has surmised, modern vehicles with electronic engine controls will not over-rev, so the chance of engine damage from over-revving is negligible to non-existent–as long as the engine has adequate lubrication.
Editorial note:
Do Tom & Ray really run “adds” (or even “subtracts”) in newspapers, in order to inform people about this issue? Perhaps T & R have a car advice column printed in that newspaper, but I really doubt that they pay for “adds” (sic) on that topic.
;-))