Looking to buy a Tahoe or Suburban. What to look for or avoid?
- Thread starter spk2000
- Start date
That's a nice looking Suburban. I actually prefer that older boxy dash to the 95+ dash, even though the layout of the factory radio controls was kind of dumb. The cloth they used then was also really nice.
Yep, nice velour. Don't make them like they used to.
Man I need to talk to you or come by and see you. I've had a rough time replacing my 2006 Sierra Denali NV149. It developed pump rub and I got a new reman and went thru 5 of them in a matter of months! Long story there but 1 word - ATK. So I took the last bad ATK rebuild to Differential & Gear in fort worth to rebuild. Guys are amazing but my 149 has a bad front cover and there are NONE to be found new and a few used ones turned out to be bad. So, they are offering me a 4481 because they think it will be better and it is my only real choice based on the 149 being hard to get a front cover. They even tried machining it with a sleeve - no go. My only concern with the 4481 is that, as I understand it, only runs 40/60 all the time split where as my 149 is 38/62 and can send up to 100% of the power to one axle if need be with the visous coupling design. D
Do you think replacing my 149 with a 4481 is going to be an ok option for me to go with? Seem like it is my only real option at this time.....again - these guys at Differential & Gear have been great in trying to help me but I am thinking I have to just take their offer of a 4481.
You opinion is Golden to me!
It will work fine 'til you actually need AWD, Without the "Vehicle Stability Enhancement System" to apply the brake & stop or limit the slip of the wheel with no traction....The T-case will act as a Open Differential. So there will be no way to bias the torque. If you do happen to get stuck....Don't try to power your way out it because the Pinions on the Carrier in the T-case will Overspeed & burn up.
I'd be pretty involved to add VSES but not impossible. You'd almost need a 2006 Escalade donor & figure out how to adapt the 2 rear wheel speed sensors to your rear differential as I don't recall any of the GMT800 pick-up's (Leaf Springs) having 4 channel ABS/VSES??
How married are you to the AWD?, I've converted a couple GMT800's to 2WD.
What about a Magna T-case out of a GMT900, Leaving the T-Case & Encoder Motor in 2-Wheel High & running like that 'til you figure out what to do? You'll need a 27 Spline Input one from behind a 4L60E. I have a 2017 K2XX T-case I'd give you....But it's 32 Spline Input.
I'd be pretty involved to add VSES but not impossible. You'd almost need a 2006 Escalade donor & figure out how to adapt the 2 rear wheel speed sensors to your rear differential as I don't recall any of the GMT800 pick-up's (Leaf Springs) having 4 channel ABS/VSES??
How married are you to the AWD?, I've converted a couple GMT800's to 2WD.
What about a Magna T-case out of a GMT900, Leaving the T-Case & Encoder Motor in 2-Wheel High & running like that 'til you figure out what to do? You'll need a 27 Spline Input one from behind a 4L60E. I have a 2017 K2XX T-case I'd give you....But it's 32 Spline Input.
I definitely want and need the AWD. I was hoping the split was 40/60 at all times. I know the ABS/VSES is involved but thought it would atleast always have something powering the front wheels. I guess I will keep an eye out for another 149 in the mean time. Since the shop can't help me with my 149 they are giving me the 4481 as it (according to them) is a close match. So if I get in mud or something it won't still have power sent to the both axles? I know it cannot bias because there is not clutch but I am ok if it is alteast always split to some degree.
THANK YOU!
The power will find the path of least resistance. So, with an open center diff and open front and rear diffs, the one tire with the least amount of traction will be spinning for all it's worth!
These traction systems use the brakes to artificially create resistance which sends the power elsewhere. Create more resistance on a wheel with no traction and that power gets sent to a wheel with traction.
I found an NP149 front case on eBay, if you're interested. https://www.ebay.com/itm/NP149-Fron...075332?hash=item28a30aa3c4:g:xHgAAOSw7ixfvtZw
If mud is the issue, a locked 4x4 without a center diff would be preferable. Jeep’s quadratrac and the older Subaru systems with the limited slip center diff were IMO the best implementations of a center diff system. I wouldn’t want an open diff in the middle, for the reasons above it will be very limited once one wheel loses purchase.
According to operational theory.......The Sun Gears that power the front & rear driveshafts act as Side Gears. If one Sun Gear is free to rotate.....In theory.....The other can be held stationary. But I don't think 40/60 split is taken into account with this oversimplified description.
Almost makes you want to remove the front shaft on one just to know for sure.
THANK YOU for that link! I understand how the overall theory is but can't understand if it's split 40/60 why it would change. I read the GM service manual description and it never makes it clear what happens when their is slippage. I've got a perfectly rebuilt 149 but the front cover hole for the bearing is out of round. A machine shop could not fix it because it;s magnesium and thin metal. The repair shop has 2 used covers that have the same issue so I am leary of ordering another used one but the link you sent said it was good an examined for wear. I may try that cover.The power will find the path of least resistance. So, with an open center diff and open front and rear diffs, the one tire with the least amount of traction will be spinning for all it's worth!
These traction systems use the brakes to artificially create resistance which sends the power elsewhere. Create more resistance on a wheel with no traction and that power gets sent to a wheel with traction.
I found an NP149 front case on eBay, if you're interested. https://www.ebay.com/itm/NP149-Fron...075332?hash=item28a30aa3c4:g:xHgAAOSw7ixfvtZw
I am so confused because like you said maybe the split is not taken into account. I read the GM manual on the operation of it and it says it has a 40/60 split. Never says what happens with wheel slip. I have a perfect rebuilt 149 but a bad front cover...that is discontiued and used ones are usually bad as well. The bearing hole is out of round and a machine shop could not fix it. My son is now asking about a 4473 case but that is a 100 rear until slip then it sends power forward via visuous couplers. I never liked on demand AWD but another option.
