best rear for towing

[roy c]

Hello again , what would be a safe rear for towing a trailer with car totalling
around 5,000 pound dana 60 or 14 bolt i also heard they made 6 lug 14 bolt
i have 87 sub with 10 bolt which when new i towed car and trailer on weekends totalling 100 miles. but since then have broken the rear twice.
thanks for any help roy c

 

[crazy4offroad]

The 6-lug 14 bolt is a semi-float, meaning the bearings ride on the axleshafts (not good). The 8-lug 14 bolt full-floater is the heavier duty version, like the D60 but has a larger diameter ring gear. !4 bolt full-floater is a lot cheaper than a Dana 60 rear as well, so it would be the obvious choice to me. Main difference between the 3/4 ton version and the 1 ton version is the width of the leaf spring mounts, 3/4 ton is 42.5" centerbolt to centerbolt like your regular 1/2 tons but the 1 ton is 40.5". Otherwise they are pretty much all the same. I think in '84 or so the pinion pilot shaft bearing was an oddball size, other than that, that's all the difference that I can think of. Of course you'll want to make sure you get one with the right gear ratio to match your front axle, or be prepared to change them to match.

 

[roy c]

best towing rear

thanks for your help. up front i have 3.23's which has to go. I'm the
original owner and never did anything except change tranny's 6x's
700 r4 last one worked finally for 11 years and counting gm factory
reman. local tranny guys loved me roy

 

[crazy4offroad]

May want to recheck that gear ratio, never heard of it. 2.73 3.08 3.54 3.73 4.10 4.56 are common ratios.

 

[roy c]

sorry about that 3.08's alittle low for haulen

 

[crazy4offroad]

I saw your other thread about swapping in a TH400 and I'm thinking a K10 with street size tires (around 31" tall) would tow pretty well with 3.73s. What tire size and sustained speed do you want to run normally? And what RPM at that speed would you like to be cruising at? You can use this gear ratio calculator to figure out what combo will get you there, or if it's too complicated (common complaint) let me know what speed/rpm/tire size and I'll punch the numbers in for you...
http://www.grimmjeeper.com/gears.html

 

[roy c]

I have 31/10.5x 15 now which works ok no more than 60 mph on the open road, I was thinking the same 3.73 -no more than 4.10 the 10 bolt rear
broke 2x's so i was going to change the rear to a 14 bolt ff are they wider than the 10 bolt? looks like the 10 bolt is crabing when i drive behind the truck when my son's driving. do you think the 44 up front could stay?
yes i have a th400 short tail good shape would also like to swap it with the 700 r4 thanks agin sir roy

 

[crazy4offroad]

I doubt you have a D44 up front, take a pic of the cover and I can tell ya if it is or not. Yes the 14 bolt is a couple inches wider, which IMO is good, the front tracks match the back better.

With those tires and trans, and assuming you have an NP208 you'll be looking at 59 MPH at 2,500 rpms. 70 mph is at around 3,000 rpms.

 

[89Suburban]

I'm the
original owner and never did anything except change tranny's 6x's
700 r4 last one worked finally for 11 years and counting gm factory
reman. local tranny guys loved me roy

Jesus, these 700r4 horror stories make me cringe.

 

[bucket]

Jesus, these 700r4 horror stories make me cringe.

Yeah, in stock form they don't like having to lug around big trucks and vans. You mostly drive around at lower speeds don't you?

 

[roy c]

Oh Sorry wrong truck I also have a 71 K20 dana 44 up front with a ho 78 or something like that, others call it a pumpkin in the back. Thanks for the calculation

 

[roy c]

yes sir 50 mph top speed for me i had gm factory reman put in back in 2001 with a tranny cooler for the first time never had a problem since, i figure when it goes i'll put in a th400 i have in the garage

 

[HotRodPC]

What is killing your 700r4's is the 3.08 gear ratio. 3.73 on down, 4.10, 4.56 etc takes alot of strain off the trans.

 

[swagger]

Hello again , what would be a safe rear for towing a trailer with car totalling
around 5,000 pound dana 60 or 14 bolt i also heard they made 6 lug 14 bolt
i have 87 sub with 10 bolt which when new i towed car and trailer on weekends totalling 100 miles. but since then have broken the rear twice.
thanks for any help roy c

My vote is for the Dana 60 its lighter than the 14 bolt, but some will say the 14 bolt FF is better cause of the bigger bearings on the pinion and its FF
When towing there are so many variables, like weight and how you load your trailer, gearing, and brakes/axles on the trailer. I have towed alot of weight with a 10 bolt! I use my trailer to carry the weight and braking the load.
Your truck (power unit) is for pulling!
Your doing so much towing and can't help to put weight on the tongue (truck)
Then get the 14 bolt FF FULL FLOATING AXLES Can handle lots of weight!

My.02
Steve

 

[roy c]

I'd pay interest on that .02 thanks now to find the right 14, due they make wider ones than others? trying to keep in better line with the front