Fellow Ram Modders!

Im sorry to bring up another gearing question, but im struggling to find the answers I need.
I got a 99 1500 with the 5.9 auto tranny, and im currently running 33s. The factory sticker says im running 3.55s with limited slip..

Does it seem right that i would be running 2500 rpms at 80mph? I thought I recalled someone on this forum saying they ran 2300rpms at 70mph with 33s and 4.10s..

 

Are you sure it is getting in to overdrive?

I don't think that is real far off....... I run about 2K RPM at 65 or so, with 265's, and 3.55 gears.

 

Yea, its definitely going into overdrive. If anything, getting into third has been a pain. Sometimes I have to shift into neutral, then drive before it hits third, and then shortly after OD kicks in.

 

Im mainly asking about the gears because Ive seen a lot of dispute here, and on other forums about gear to tire ratio.. I dont feel like my gears now are terrible, but im already looking at having the pinion bearing serviced..

 

I think your speedo is off..... But, in all reality, if you are getting 4th gear, that seems really high, considering you should be around 1600 at 65 mph...... If everything is accurate, you are about 300 RPM high.......

Probably, correcting for speedometer error, that would put you right in the ballpark though....

Really, for 33's, 4.10 would be a better ratio. Keep the engine more in the power band at cruising speeds. Having your speedometer corrected wouldn't hurt either..... Any decent shop with a good scanner should be able to do that.

 

You might be going in to overdrive, but, might not be going into lockup, there would be your additional 300 rpms..

 

4:10 would definitely fit your setup better, go 4:56 if you plan on getting 35s in the future. i just put in 4:56 with my 35s and jesus, i didnt know this truck had so much power being robbed before with the 3:55s

 

Im glad i posted this on here, cause i think your right on with the speedo not being calibrated. I have access to a tuner, I will give that a shot this afternoon! I feel like my truck has pretty good pep coming off the line as is, but i definitely notice a lag in power when I get on the gas at highway speeds.

 

Thats a good point.. Do you have a ballpark number for how much the rpms should drop (total) when OD is fully/correctly engaged?

 

Glad to get some input from another 3.55er. I dont plan on going any bigger than 33s, (just spent 1500 on rims and tires) so if anything I will probably go with 4.10s like you guys have suggested. I do a little bit of everything with this truck, so I was wondering if you guys have an idea of what rpms 4.10s would put me in going 75-80mph? Thanks a lot for your help guys!!