Transmission shifting issues when climbing mountain passes

[TheSasks]

Originally Posted by Glenn5995

Like M109Rider said "gotta love the 545RFE". Fortunately Power Wagons have 4.56s gears OEM, so that helps quite a bit and with mine being a 2006, I can hold it in any gear, which is a huge benefit. The 2005s and earlier had no way to keep it from shifting between 3rd and 4th.

The problem you had was because of the wide spacing between 2nd Prime and 1st. The 545RFE is marketed as a 5-speed because it functions in that manner, but it actually has 6 forward gears. Because of the wide spacing between gear ratios there is an alternate 2nd gear for downshifts which is higher than the 2nd gear used for upshifts. As a result when it downshifts from third, it is a gear ratio that is closer to 3rd and a LOOOOOONG way from 1st. The result is the transmission can't downshift into first until the speed has dropped enough to permit the downshift without over revving the engine. The result is exactly as you described, you keep pushing on the gas pedal, but the speed and RPMs keep dropping until they are low enough to allow a downshift.

I have learned to cheat it if I'm in an area I am familiar with and can anticipate the grade. Before the grade, I will slow enough to manually pull it into first gear and then put the selector into 2nd and allow it to UPSHIFT into 2nd (the lower 2nd gear) and stay there. By not allowing it into 3rd, it won't DOWNSHIFT into 2nd prime. By doing this grades that otherwise would have forced me to slow and drop into 1st, I am able to maintain a higher speed and stay in 2nd.

Great idea Glenn.

[M109Rrider]

Right on Glenn. 2nd prime is also a weak link in the 545. It uses a weaker band (the reverse band I believe) with less holding power and is prone to burning up, particularly in modified trucks.

[sherdep]

I have the Superchips programmer with the shift point options but I am running 35" tires with 3.92 gears.
Mine doesnt hunt gears as bad but it lags before it finally down shifts.

you will most lilkely need to change your tune for the shift points.

When I was a Beta tester we had a Xcel spread sheet with a graph that allowed you to see your shift points but I never got the hang of it cause it was a pita to keep changing and tuning and changing and tuning

I know on Dodgetalk.com there was a big discussion on the shift points when superchips came out with the programming for it - as a matter of fact my truck was a beta tester for the shift points for a 3rd Gen Ram.

[KyDan]

Dang, kinda makes me long for the old days when trucks were
manual tranny and we were all gear jammers on the hills.
(I actually drove milk/dairy trucks that had manual trannys that did
not have synchronizers so you had to double clutch to change gears.
They had 2 speed rear ends too.)

[FarmerMT]

Thanks for all of the information. My truck does have both the tow/haul and O/D shut off options. I did not try the O/D off. My Bully Dog does allow me to change shift points. I need to research some towing shift points for it and set what RPM it will shift at for each gear. I will only travel this type of pass twice a year (thank goodness) I had no problems at all on long steep grades just this one pass that went very steep over a short distance.

[08flagvlite]

Not to change the subject, but on the 545 RFE, have any of you heard of using DextronIII, and then using an "additive" to convert it to ATF+4? This is exactly what AAMCO is doing because the ATF+4 is a fully synthetic fluid, and about 2.50 a bottle more than Dex 3. That way they keep down their cost of a trans fluid and filter service. Makes me wonder if it is okay to do that! The dealer of course says to use ATF+4, as stated on the stick, spec.9602.
My son's 95 Dodge Ram 1500 5.2 has a 46 RH tranny that we just yesterday rebuilt and re-installed in his truck. t says on the stick Chrysler spec.7176 fluid, OR Dextron 2.
Why are Dodge trannys so confusing!! I put ATF+4 spec 7176 on the bottle from Oreilly's at 5.69 per bottle synthetic, just to be safe. 60.00 worth of fluid by itself! Works good though. Randy