So, is driving faster than 70mph ok with 5.13's, 35's , 3.8l, and auto? Remember something about drive shaft rpm's being to high, will the 5.13 not let you go much faster? Getting ready to re-gear to 5.13.

 

That's what I run. No issues at all - 2+ years.

 

Measure your tires and plug the numbers into the chart.

The problem with the driveshaft rpm's has to do with the overall build. Lift height, aftermarket driveshaft joints, too much caster, vibes getting to the tcase, boom...

I was running a Woods front shaft with 5.13's and short 35's (measured 33.5") with no problems. Then went to 5.38's for a year or so before moving up to 37's. RPM was never an issue for me.

 

I have this set up but don't drive over 70 mph. It would probably be fine I just don't drive that fast. I like it. Mostly driving around town though

 

You'll be alright. I cruise at 70 all the time with the same setup and often do 80 for long periods of time without issue. If the shaft is balanced, not damaged and your angles are good you'll be alright.

 

5:13's are a perfect gear for the 3.8 auto on 35's. I've been running them for about a year 75-80 mph is no problem...

 

I have 35s with 513s and do get drive shaft vibe with my stock ds in the 75-80mph range. I have a 2.5 inch RK lift and tore my boot on mu srock ds in the trans oil pan lip. It needs to be replaced with a woods or adams ds. I just keep it at 74 or less and I'm happy. I think 513s are good for the max upper range of 35s. Just be prepared to need a new ds. Done 800 mile round trips twice to MOAB like that. Some day I'll buy a front ds to replace my worn stock one. Probably this year.

 

If you have the matching gear ratio to tire diameter then the driveshaft and engine rpms should be the same as stock. Any shaft issues would be the result of something else.
Roughly saying that 4:10 - 32" should be about 5:13 - 35".
Yes / No ?

 

I drive 35+ miles one way to work 5 days a week and drive 75-80 most of the time. I have 5.13's and 35" general grabbers all is good with mine.