Questions about 4x4 4 hi & 4 lo

[driven_mad]

I am looking at buying an 08-14 suburban. I have found an 08 with the 4spd and 3.73 gears and I have noticed that it also has 4lo in 4x4 mode.

Is this a desirable combination with the 3.73 and given that the 09+ models have only 4hi?

Any recommendations?
I don't usually tow more then 4000 lbs and not often as of late

 

[Mickey_7106]

i have an '09 with a 6speed 4hi and 4lo. Think the only time you'll need 4lo is when you're in deep mud, snow or sand where maximum traction is needed at a very low speed. Taller gears are better for towing but if its only 4k lbs you can definitely go with a 6speed and 3.42. probably save a 1-2 mpgs in the process

 

[swathdiver]

I am looking at buying an 08-14 suburban. I have found an 08 with the 4spd and 3.73 gears and I have noticed that it also has 4lo in 4x4 mode.

Is this a desirable combination with the 3.73 and given that the 09+ models have only 4hi?

Any recommendations?
I don't usually tow more then 4000 lbs and not often as of late

2010-2014 4x4s with 6-speed transmissions and if equipped with 3.08 (GU4) gears will have the MP3010 single speed transfer case (NP0).

2009-2014 4x4s with 6-speed transmissions and if equipped with 3.42 (GU6) gears will have the MP3023 2-speed transfer case (NQH).

These combinations are more versatile than the older 4-speed trucks with 3.73 gears. Fourth gear with the 6-speed and 3.42s delivers a 3.94:1 ratio, great for towing. Drop down to 3rd and the ratio is 5.23:1. First gear is 13.76:1 with 3.42s.

Some of those 2008 and 2009 Suburbans will have the 6.0 L76 motor. This is not a FlexFuel engine and it does have VVT and AFM. The 2008s will have the 4-speed (4L70 Supermatic), the 2009 will have the 6L80.

The newer you go the more refined the navigation unit, bluetooth for phone (2009+), Hill Start Assist, Sway Control in 2012 and other cruise control improvements in 2012-2013.

Back to the transfer case, I find it useful when we need to get the wheels spinning fast at low speed, for getting out of wet grass or mud or crossing a stream, etc.

The 3.08s are great for a highway or street cruiser but not desirable if you plan to tow or want more get up and go or to play off road.

If you want maximum capacity cooling and towing, look for a truck equipped with K5L, KNP, KC4, GU6. All GMC Yukons have the G80 locker (locking limited slip), for Chevrolet it was an option.

 

[driven_mad]

2010-2014 4x4s with 6-speed transmissions and if equipped with 3.08 (GU4) gears will have the MP3010 single speed transfer case (NP0).

2009-2014 4x4s with 6-speed transmissions and if equipped with 3.42 (GU6) gears will have the MP3023 2-speed transfer case (NQH).

These combinations are more versatile than the older 4-speed trucks with 3.73 gears. Fourth gear with the 6-speed and 3.42s delivers a 3.94:1 ratio, great for towing. Drop down to 3rd and the ratio is 5.23:1. First gear is 13.76:1 with 3.42s.

Some of those 2008 and 2009 Suburbans will have the 6.0 L76 motor. This is not a FlexFuel engine and it does have VVT and AFM. The 2008s will have the 4-speed (4L70 Supermatic), the 2009 will have the 6L80.

The newer you go the more refined the navigation unit, bluetooth for phone (2009+), Hill Start Assist, Sway Control in 2012 and other cruise control improvements in 2012-2013.

Back to the transfer case, I find it useful when we need to get the wheels spinning fast at low speed, for getting out of wet grass or mud or crossing a stream, etc.

The 3.08s are great for a highway or street cruiser but not desirable if you plan to tow or want more get up and go or to play off road.

If you want maximum capacity cooling and towing, look for a truck equipped with K5L, KNP, KC4, GU6. All GMC Yukons have the G80 locker (locking limited slip), for Chevrolet it was an option.

Thank you for this is great info. It's hard to find these trucks in my area and with the options that I want. And I kept wondering why on earth would General Motors make an xl/burb without a 4lo and now I understand.

That leads me to eliminate anything without a 2 speed transfer case in my search. I have located a few 08 xl models I'm assuming with the 4spd and 3.73's. One in particular with 195k and a low price that I may consider for a few seasons if the drivetrain is solid. Which would then give me more time to find something more ideal for the longer run. I'm starting to lean more towards the Yukon of these years I think I like the smaller nose better too.

Is there anything that I should look out for with a high milage 2008 xl slt?.. I have read about the afm issues causing lifter problems,, not sure if I've overlooked anything else...

 

[swathdiver]

Thank you for this is great info. It's hard to find these trucks in my area and with the options that I want. And I kept wondering why on earth would General Motors make an xl/burb without a 4lo and now I understand.

hat leads me to eliminate anything without a 2 speed transfer case in my search. I have located a few 08 xl models I'm assuming with the 4spd and 3.73's. One in particular with 195k and a low price that I may consider for a few seasons if the drivetrain is solid. Which would then give me more time to find something more ideal for the longer run. I'm starting to lean more towards the Yukon of these years I think I like the smaller nose better too.

Is there anything that I should look out for with a high milage 2008 xl slt?.. I have read about the afm issues causing lifter problems,, not sure if I've overlooked anything else...

My pleasure. My first truck was 799 miles away, the second was 2600 miles away. They have the exact options that we were looking for.

AFM on these early models often failed by around 100K miles. It's not an expensive repair or delete if you do it yourself. By the middle of 2011, GM had updated the VLOM, lifters and driver's side valve cover to reduce oil consumption.

The 2007-2009 5.3 engines all have AFM and do not have VVT. Their camshafts are a single pattern grind and is the same as the L33 Generation III engine.

Most vehicles this age are going to require some repairs and maintenance. Most of us spend a few grand on new buttons, floor mats, tune ups, shocks, brakes, etc. to get them in tip top shape again.

It's near impossible to work on them without a bi-directional scan tool and access to the shop manual (AllDataDIY). The Tech-2 for example often allows you to quickly diagnose a problem instead of firing the parts cannon at the car trying to see what works which is a waste of time and money. They pay for themselves in short order, usually after the first repair even. Shop rates are well over $100 these days.

 

[driven_mad]

My pleasure. My first truck was 799 miles away, the second was 2600 miles away. They have the exact options that we were looking for.

AFM on these early models often failed by around 100K miles. It's not an expensive repair or delete if you do it yourself. By the middle of 2011, GM had updated the VLOM, lifters and driver's side valve cover to reduce oil consumption.

The 2007-2009 5.3 engines all have AFM and do not have VVT. Their camshafts are a single pattern grind and is the same as the L33 Generation III engine.

Most vehicles this age are going to require some repairs and maintenance. Most of us spend a few grand on new buttons, floor mats, tune ups, shocks, brakes, etc. to get them in tip top shape again.

It's near impossible to work on them without a bi-directional scan tool and access to the shop manual (AllDataDIY). The Tech-2 for example often allows you to quickly diagnose a problem instead of firing the parts cannon at the car trying to see what works which is a waste of time and money. They pay for themselves in short order, usually after the first repair even. Shop rates are well over $100 these days.

Sounds like I should stay away from 07-09 unless perhaps they have been maintained well.

So the 2010+ 5.3 with VVT is going to have less issues overall ?

I've also found a 2010 xl slt with the same milage but better maintenance, for about twice the price. I'm just not sure if I'd want to spend that much on something with that milage and the interior doesn't look as nice, but with the better maintenance and 6 AT/3.42 maybe is a decent option

 

[Doubeleive]

don't forget the powertrain grade braking, sure saves my brakes on long downhill decents even if I am not towing anything, you can tap the brakes and just cruise at speed without having to brake hardly at all. I believe it is only available on the 2012+
"Grade Braking assists in maintaining desired vehicle speeds when driving on downhill grades by automatically implementing a shift schedule that utilizes the engine and transmission to slow the vehicle. This reduces wear on the braking system and increases control of the vehicle. Grade Braking monitors vehicle speed, acceleration, engine torque and brake pedal usage. Using this information, it detects when the vehicle is on a downhill grade and the driver desires to slow the vehicle by pressing the brake"

 

[driven_mad]

I decided to go with the lower cost 2008 xl slt



It has the 5.3 with 3.73 and towing package. I'm not sure how I like the 20" rims yet, I think I may get a set of 18's and new tires for the winter season. What do you guys think?

Engine and interior are clean

 

[Geotrash]

View attachment 380623I decided to go with the lower cost 2008 xl slt
View attachment 380624


It has the 5.3 with 3.73 and towing package. I'm not sure how I like the 20" rims yet, I think I may get a set of 18's and new tires for the winter season. What do you guys think?

Engine and interior are clean

Love it! Looks clean.

 

[Dustin Jackson]

@driven_mad Congratulations man, mine is also an 08. They are great rigs, educate yourself on the AFM thing just in case.

My Tahoe also has 20 inch wheels but after I put 33 inch tires on them they don't look too bad.