Do engine RPMs have anything to do with transmission shift points

[Brian Alcorn]

Ok so my question is ...do rpm of the engine have anything to do with transmission shift points ...
Needed info
2004 Rubicon auto 42rle
5.13 gearing
265/75/16
Speedohealer

Problem is it's shifting into overdrive before 35mph unless I'm hard on the gas .. at least halfway to the floor or is this a sign the trans is going bye bye .. I've heard from several sources including here that the trans won't last as long as this milage so what's the average milage life of the 42rle

 

[qslim]

If the trans is on its way out then I’d say you got your money’s worth.

I can’t speak to the 42RLE specifically as far as your question about symptoms, but yes RPM plays a role on the transmission’s shift points.

Is it behaving differently than it has in the past? I know my wife’s Lexus does the same thing - it’ll drop into 6th gear right away but I’ve been told it’s programmed to do that for fuel economy. I usually drive it around in manual mode just because it’s really annoying to always wait for an up shift.

 

[Tob]

5.13 gearing
265/75/16

Seems pretty deep for an almost stock tire size. Did you or PO downsize tires?

 

[pagrey]

The transmission uses input/output shaft speed to determine shift points and engine rpm. Keep in mind that's overdrive about 48 mph in a stock TJ or 44 in a Rubicon which is normal. I don't think you have transmission problems.

Edit: input output and rpm to determine shift points, garble garble

 

[jjvw]

Seems pretty deep for an almost stock tire size. Did you or PO downsize tires?

Lower rpms than most would expect.

42rle/32”/5.13=2788rpm @ 75mph
42rle/30”/5.13=2973rpm @ 75mph

 

[Brian Alcorn]

Ok so yes I had it regeared a few months ago ... rear had bad pinion bearing and a shop did front and rear for $1326... wanted to wait but it just kinda happened ... going 35s when these are bald ... just recently got speedohealer hoping to alter shift points but if engine rpm plays a part then tires is the only logical step ... .. went 5.13 for 35s . Maybe a little deep for those buy with such a low overdrive ratio it's needed plus added weight of the tires... like Jerry B said I shoulda went 5.38 for 35s but not regearing again

 

[pagrey]

Unfortunately the 42RLE doesn't use the speedometer input at all, there has been some back and forth about this in the past but I've played with mine quite a bit and it hasn't changed a thing. You definitely aren't hurting anything, that early lockup means the transmission is under very light load.

 

[Mrholland]

Reprogram the trans and drive it more aggressively and it'll get better.

 

[Brian Alcorn]

Reprogram the trans and drive it more aggressively and it'll get better.

Please explain

 

[Jerry Bransford]

Your speedometer is completely accurate with the Speedohealer? I don't know how/if the speedometer affects when the 42RLE shifts but it definitely did with my previous 32RH automatic.

 

[Brian Alcorn]

Your speedometer is completely accurate with the Speedohealer? I don't know how/if the speedometer affects when the 42RLE shifts but it definitely did with my previous 32RH automatic.

Yes -20% is spot on with 2 gps apps

 

[Mrholland]

Please explain

Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory. Reconnect the Battery Cable Turn Ignition Switch to the “On” position but DO NOT start the engine Turn Headlight “On” Turn Headlights “Off” Turn Ignition Key “Off”