Yukon Posi vs Detroit TruTrack

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hunters628

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I’m gonna re gear the axles in my k10 and I wanna throw some sort of posi in my rear end. I’m looking at either a Yukon Posi or a Detroit TruTrack and wanna know your thoughts. The truck will do 90% on road and freeway driving and the only of road will be well worn trails through the woods here in eastern Washington. We do get good amounts of snow here. I’ve read that the TruTrack is great for both and is virtually indestructible. Don’t know much about the Yukon. Not sure how tough the Yukon’s are but I’ve heard the Detroit is legendary. I know the Yukon requires a friction modifier and the Detroit doesnt. What are your guys thoughts. Let me know.
Thanks
Hunter
 

Swearbody

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Ive never had either but I have had a OE gm posi and Im pretty sure the Yukon posi is the same thing. Clutch type that will need adjustments and wear more. I am about to do 4.10's and a trutrac on mine...just waiting on the local off-road shop to open back up, I figure they do them all the time so Ill go there. I asked the guys at the shop and they said the trutrac is set it and forget it, and can easily handle more than ive got,lol.
 

77 K20

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I have the truetrac in the front of my truck and a friend has it in the rear of his.

I'd take it over a posi as there are no "wear parts". Just gears. The gears like conventional oil vs synthetic oil.
 

shiftpro

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Before you buy new, look for a 14 bolt with a locker already in it. You could find one that will cost less than a new locker and have a real man's diff instead of the wimpy 10 or 12 bolt whatever is in your truck. Sounds like you might want to move up a tire size or two, so look for that 14 bolt with your
lower ratio in mind. Then you'll want even bigger tires and may as well slide D60 up front. Then comes the big block!
 

hunters628

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Before you buy new, look for a 14 bolt with a locker already in it. You could find one that will cost less than a new locker and have a real man's diff instead of the wimpy 10 or 12 bolt whatever is in your truck. Sounds like you might want to move up a tire size or two, so look for that 14 bolt with your
lower ratio in mind. Then you'll want even bigger tires and may as well slide D60 up front. Then comes the big block!
The only reason I want to keep the 10 bolt is so I can keep my wide steels with caps. I’ll be running 33s stock height and the truck has a 5.3 in it. The truck has 3.08 gears in it now and first gear in the th400 with the rest of that combo is like 13 mph at idle if I remember correctly. I’ll be going to 3.73 gears. I thought about getting a 14bsf that was already 6lug because most of them were 3.73 but I’m having a hard time finding one and I’m not sure my wheels would fit the drums.
 

BKING33

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Go with the True Trac. I have about 16,000 on one in my Suburban and works great. My last truck had a OE style slip posi.
I had to reshim the clutch plates twice in about 40,000 miles.
 

Vbb199

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If you have a heavy foot and are running larger than stock tires on the cheesy 10 bolt, dont get a detroit.
You'll remember me saying that when one of your axle shafts and tires walks out of the axle tube if ya get my drift.

My stock g80 unit in my suburban works just fine... wouldnt remotely consider any sort of "harsh" locker in its 10 bolt with the power my sbc makes unless i upgraded the carrier and axle shafts.

The ONLY think id consider (and ive been saying it) is a grizzly locker.
Locks in solid like a detroit, but unlocks on turns, unlike a detroit.
 

RoryH19

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The only reason I want to keep the 10 bolt is so I can keep my wide steels with caps. I’ll be running 33s stock height and the truck has a 5.3 in it. The truck has 3.08 gears in it now and first gear in the th400 with the rest of that combo is like 13 mph at idle if I remember correctly. I’ll be going to 3.73 gears. I thought about getting a 14bsf that was already 6lug because most of them were 3.73 but I’m having a hard time finding one and I’m not sure my wheels would fit the drums.

Similar to the setup on my k5. Came with 3.08's then I swapped for 10 bolt 3.73's from another k5.
I now have a 3.73 14BSF rear from a 94 2500 light duty Chevy 4x4 in 6 lug. Came with a limited slip but as you mention hard to find.
 

J-Bob

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I just finished installing 3.73’s and TruTrac Sunday. I’ve only driven it 70 miles since and break in says to take ‘er easy first 500 miles. I’ll smoke ‘em down and re-post late next week!
 

Mark Vucelick

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I had a tru-trac fail open in an automotive application in a chrysler 8 3/4 rear end. Randys sold it to me initially. Upon additional phone conversations with them, they refunded me my money and sold me a detroit locker telling me "the helical style locker is not really strong enough for your application". The detroit locker is UN-noticible in the car, and seemed to be much less "clunky" than the detroit lockers i have used in 14 bolts and dana 60 front ends 20 years ago.
 

TPISly-C10

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Yukon here working good on my 10 bolts diff oem 3:42 gear! for $410 best buy for quality ;)

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Craig Nedrow

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Hey Hunter you live in my neck of the woods, and welcome. I installed a lunchbox locker in my 14 bolt, Yukon, and detail it on my build page. Blew up the TH350 with the 454, but the rear end is great. I was wondering what year your truck was, as my 73 K10 has a posi 12 bolt rear and ten bolt front. If you would like welcome to come look at my stuff, look at the thread, gain some knowledge, and make a informed decision. The truck 12 bolt has the small pinion support bearing, so not as strong as the car 12 bolt. However, this truck has NEVER had a problem with the rearend, (stock posi) has probably 100,000 off road miles, hauled many ridiculously overloaded loads, puller a hay trailer consistently with 8000+ still going. The 14 bolt is much better choice if you want to haul heavy loads IN THE BED, as it is a full floater, (ff). I just looked on marketplace, and craigs list, lots of complete, or parting out's there reasonable.


https://www.gmsquarebody.com/threads/1973-k20-350-to-454-swap.29840/
 

Craig Nedrow

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Hey Hunter you live in my neck of the woods, and welcome. I installed a lunchbox locker in my 14 bolt, Yukon, and detail it on my build page. Blew up the TH350 with the 454, but the rear end is great. I was wondering what year your truck was, as my 73 K10 has a posi 12 bolt rear and ten bolt front. If you would like welcome to come look at my stuff, look at the thread, gain some knowledge, and make a informed decision. The truck 12 bolt has the small pinion support bearing, so not as strong as the car 12 bolt. However, this truck has NEVER had a problem with the rearend, (stock posi) has probably 100,000 off road miles, hauled many ridiculously overloaded loads, puller a hay trailer consistently with 8000+ still going. The 14 bolt is much better choice if you want to haul heavy loads IN THE BED, as it is a full floater, (ff). I just looked on marketplace, and craigs list, lots of complete, or parting out's there reasonable.


https://www.gmsquarebody.com/threads/1973-k20-350-to-454-swap.29840/
 
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