need help with rear for tow rig.. off topic but you guys will know the answer

R

rayjon

Venimus, Vidimus, Deus vi
I have a 3500hd chevy 1995 with a 37 spline dana 80 in it, Did a cummins swap and working on a fuller 10 speed now, the problem I have is the 3.54 gear set I swapped into the dana 80 isn't working on the highway. I need 3.08 and something a little stronger if possible..

Here is my delema I have a small 10 lug pattern 7.5 not the metric pattern ford uses so a s110 is out.

Does anyone know of a rear that is bigger than a dana 80 comes in 3.08 and uses the old chevy mini 10 bolt pattern with Juice brakes..

I can also convert the brakes if ends are similar..

Thanks for the help
 
the tires are 225/70/19.5 brand new all the way arround, cant really step up on the tire size due to the custom hauler bed i built and level of the truck now.. Its a crew cab built by monroe truck for a local city 18k gvw that I picked up second hand with 30k miles on the clock and a dead 6,5

the 10 speed will be an rto610 have a rt610 and am changing the gears to make it an rto

what I am trying to get to is under 2000 rpm running empty on the highway, Nevada is big and I have found with my other trucks if I keep the cummins under 2k I can get 20+ on the highway. that is the goal.. and with the 10 speed I will have all the gearing I will need, not to worried about breaking the dana 80 with only 350hp but would like to drop the rpm some more at 70mph.. I have the turbo and low end to pull the gear.. just trying to figure out how to get there with this combo.

thanks for the quick response..
 
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How tall are the 19.5.I was running 2300 at 70mph with 29" 235/70/16 3.54 .80od.I got 25 empty.You will have the same OD as the RTO6610 once you switch over.With the allison 6sp I will be doing 1728rpm at 70mph when I get the truck back togetherOD in the allison is 5th.71:1 and 6th .62:1.My speedo was on the money with a GPS.So if your tires are taller than mine your RPM will be alittle less.

Dale
 
the 19.5's are about 32" with the nv4500 I was at about 2100 at 70mph, the differnce isn't much but it should go up just a tad as the nv4500 is .75 and the rto is .80 in overdrive.. I will give it a while and run the 3.54 like you sugest and see what it does..

did find that the dana 135sl has ratios down to 2.61 and all I would have to do is swap the hubs off my 37 spline dana 80..
 
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