Are you looking to build the ultimate S-10 or Blazer? Here is a guide to the best and strongest stock and aftermarket parts you will want for your build:
Transfer Case:
Alright the transfer case that comes in any 4x4 S10 is either a 207, 231, 231HD, 233, 236 autotrac. The
autotrac was only an option in the blazers.
The 231 and 231HD were the manual shifted transfer cases and were only an option up to 1997. These
are the strongest and best option to put in a S10 as they are a complete bolt in and remove the vacuum
line and electronic switch found in most 2nd generation S10's. There were two different types of 231
manual shifted transfer cases, a linkage set up found on first gen body S10's and a cable set up found
on second gen body s10s. If you have a 1995+ the cable actuated is the easiest and direct swap.
the 233 is the 3 button transfer case found in most S10's it usually contains the "HD package" which
includes a wider chain and 6 planetary gears.
the 236 autotrac is the 4 button transfer case that featured an auto button that used clutches in the
transfer case to engage 4x4 when it felt the wheels slip.
For 2nd generation S10 owners the best setup to swap into your truck is to get a 231 transfer case and
center console out of 2nd gen that had the manual transfer case. Then rebuild the transfer case with the
6 planetary gears and the wide chain and gears. Any of the holes that need to be drilled are all indented
in the sheet metal from the factory. A relay also needs to be installed to ground a pin on the computer
so that it goes to different shift tables when in four wheel low.
autotrac was only an option in the blazers.
The 231 and 231HD were the manual shifted transfer cases and were only an option up to 1997. These
are the strongest and best option to put in a S10 as they are a complete bolt in and remove the vacuum
line and electronic switch found in most 2nd generation S10's. There were two different types of 231
manual shifted transfer cases, a linkage set up found on first gen body S10's and a cable set up found
on second gen body s10s. If you have a 1995+ the cable actuated is the easiest and direct swap.
the 233 is the 3 button transfer case found in most S10's it usually contains the "HD package" which
includes a wider chain and 6 planetary gears.
the 236 autotrac is the 4 button transfer case that featured an auto button that used clutches in the
transfer case to engage 4x4 when it felt the wheels slip.
For 2nd generation S10 owners the best setup to swap into your truck is to get a 231 transfer case and
center console out of 2nd gen that had the manual transfer case. Then rebuild the transfer case with the
6 planetary gears and the wide chain and gears. Any of the holes that need to be drilled are all indented
in the sheet metal from the factory. A relay also needs to be installed to ground a pin on the computer
so that it goes to different shift tables when in four wheel low.
Rear Axle:
S10’s came with several different rear axles that were all “ten bolts”
The S10 came with a 7.5”, 7 5/8”, 8.5”, or an 8.6”. S10 crewcabs with the 7 5/8” axle and S10’s with
the 8.6 came with rear disk brakes. Also many second generation 4x4 blazers had disk brakes.
The code G80 in your glove box means that your vehicle came with a factory automatic locking rear
differential made by Eaton. This unit does wear out and will require a rebuild or replacement with a
different unit. For a replacement you have many options depending on your axle if you DID NOT have
a code G80 then you have the option of installing a “lunchbox” locker that installs by replacing the
spider gears in your carrier. For those with a G80 code or seeking a locker with more strength you can
replace the carrier with either a limited slip unit or a full locking differential. A limited slip can either
be a clutch type or a gear driven unit and uses friction to distribute a predetermined amount of torque to
each wheel. A full locking differential will distribute 100 % of torque to both wheels. For full lockers
there are several options including a selectable locker a full time locker or spool. A selectable locker
can be broken down into electric such as the Eaton unit, or air such as the ARB unit. There is also an
option for a limited slip differential with full electric locking capability by Auburn. A spool is an
option for vehicles which rarely see the street as they are a direct mechanical connection between both
axle shafts. Welding the spider gears is also an option commonly called a “Lincoln locker” this is not
recommended unless done by a professional and not meant for street use.
The S10 came with a 7.5”, 7 5/8”, 8.5”, or an 8.6”. S10 crewcabs with the 7 5/8” axle and S10’s with
the 8.6 came with rear disk brakes. Also many second generation 4x4 blazers had disk brakes.
The code G80 in your glove box means that your vehicle came with a factory automatic locking rear
differential made by Eaton. This unit does wear out and will require a rebuild or replacement with a
different unit. For a replacement you have many options depending on your axle if you DID NOT have
a code G80 then you have the option of installing a “lunchbox” locker that installs by replacing the
spider gears in your carrier. For those with a G80 code or seeking a locker with more strength you can
replace the carrier with either a limited slip unit or a full locking differential. A limited slip can either
be a clutch type or a gear driven unit and uses friction to distribute a predetermined amount of torque to
each wheel. A full locking differential will distribute 100 % of torque to both wheels. For full lockers
there are several options including a selectable locker a full time locker or spool. A selectable locker
can be broken down into electric such as the Eaton unit, or air such as the ARB unit. There is also an
option for a limited slip differential with full electric locking capability by Auburn. A spool is an
option for vehicles which rarely see the street as they are a direct mechanical connection between both
axle shafts. Welding the spider gears is also an option commonly called a “Lincoln locker” this is not
recommended unless done by a professional and not meant for street use.
Front Axle:
All 2nd generation 4x4 5 speed S10's came with a cast iron front differential housing instead of the
weak aluminum housing found in automatics.
Front axle shaft…
Oldsmobile Bravada's came with a one piece front axle shaft instead of the slide collar found in all
other S10 4x4 front axle housings that is weak. A shaft out of a stock bravada can be used but it
requires the outer c-clip to be removed. Outfitter Design LLC now sells an upgraded alloy shaft that
allows both C-clips to be retained.
Front locker…
There currently is not an option for a selectable locking differential for the front differential. The only
option is the powertrax PT1935 which installs into the carrier and is a automatic locking differential
that engages when you have your foot on the gas and disengages when coasting. WARNING: This may
cause accelerated wear of front end components and should not be used with an aluminum differential.
For the strongest setup get an iron front differential from a 4x4 5 speed and install a bravada front axle
shaft and axle tube housing. Make sure you get a front diff out of a truck with the same gear ratio or
you will need to regear. All ZR2's came with 3.73 gears.
weak aluminum housing found in automatics.
Front axle shaft…
Oldsmobile Bravada's came with a one piece front axle shaft instead of the slide collar found in all
other S10 4x4 front axle housings that is weak. A shaft out of a stock bravada can be used but it
requires the outer c-clip to be removed. Outfitter Design LLC now sells an upgraded alloy shaft that
allows both C-clips to be retained.
Front locker…
There currently is not an option for a selectable locking differential for the front differential. The only
option is the powertrax PT1935 which installs into the carrier and is a automatic locking differential
that engages when you have your foot on the gas and disengages when coasting. WARNING: This may
cause accelerated wear of front end components and should not be used with an aluminum differential.
For the strongest setup get an iron front differential from a 4x4 5 speed and install a bravada front axle
shaft and axle tube housing. Make sure you get a front diff out of a truck with the same gear ratio or
you will need to regear. All ZR2's came with 3.73 gears.
Lift Kits:
Lift kits…
To fit 33's on a ZR2 you can install a 2" or 3" bodylift from performance accessories or BDS and do
some minor trimming. Glass fenders and bedsides are also another option. Also I have seen
33x10.5x15 be installed with lots of trimming to the wheel wells on a stock height ZR2.
As far as suspension lift kits there are five main options:
1. 6” Superlift. This kit is unique in that it contains a steering support system that relieves some stress
on the idler and pitman arm.
2. 2” Superlift. This kit can be described as an expensive torsion bar crank with rear lift shackles. It
includes replacement control arms that relieve the ball joints of extreme angle when the torsion bars are
adjusted beyond Z-Height (This is a calculated factory allowed height). Accelerated CV wear is
common in many cases.
3. 5” BDS. This kit is excellent for the sake that it has a lifetime warranty but is specific to the ZR2. It
does not have the steering support that the Superlift kit has. BDS's ability to retain suspension
geometry has come into question. They use extended tierod sleeves as well.
4. 5” Trailmaster. This kit is only for the regular S10 NOT ZR2
5. 2.5” Rough Country. This kit is new on the market and features tubular upper control arms that
utilize fullsize silverado balljoints. A differential drop bracket is used to lower the differential
but requires the housing to be cut. The kit also included extended rear shackles, new torsion bar
keys and upgraded shocks. This kit really improves the strength in the upper control arm area
but some have experienced contact with the rim and the upper control arm.
To fit 33's on a ZR2 you can install a 2" or 3" bodylift from performance accessories or BDS and do
some minor trimming. Glass fenders and bedsides are also another option. Also I have seen
33x10.5x15 be installed with lots of trimming to the wheel wells on a stock height ZR2.
As far as suspension lift kits there are five main options:
1. 6” Superlift. This kit is unique in that it contains a steering support system that relieves some stress
on the idler and pitman arm.
2. 2” Superlift. This kit can be described as an expensive torsion bar crank with rear lift shackles. It
includes replacement control arms that relieve the ball joints of extreme angle when the torsion bars are
adjusted beyond Z-Height (This is a calculated factory allowed height). Accelerated CV wear is
common in many cases.
3. 5” BDS. This kit is excellent for the sake that it has a lifetime warranty but is specific to the ZR2. It
does not have the steering support that the Superlift kit has. BDS's ability to retain suspension
geometry has come into question. They use extended tierod sleeves as well.
4. 5” Trailmaster. This kit is only for the regular S10 NOT ZR2
5. 2.5” Rough Country. This kit is new on the market and features tubular upper control arms that
utilize fullsize silverado balljoints. A differential drop bracket is used to lower the differential
but requires the housing to be cut. The kit also included extended rear shackles, new torsion bar
keys and upgraded shocks. This kit really improves the strength in the upper control arm area
but some have experienced contact with the rim and the upper control arm.
Now to our favorite part....SUSPENSION!
There currently is no long travel 4x4 kit on the market or any CHEAP way to long travel your
4x4 but I have identified several ways to get a few inches out of your stock set up.
Rear suspension…
To level your sagging rear suspension on your blazer you can get 2" lift shackles, add-a-leaf,
Monroe air shocks PN:MA764, Deaver replacement leaf packs, or go custom. Lift blocks WILL
NOT WORK as S10's have a spring under axle set-up.
Swaybar…
The basic 4x4 S10 came with a front sway bar. A ZR2 S10 truck came with a front swaybar and
a rear track bar. The blazers came with front and rear swaybars.
I have removed the rear sway bar on every blazer I have owned. Also I have removed my front
swaybar without issue and have had a much more comfortable ride and it handles much better
offroad. DO THIS WITH CAUTION as more body roll is induced and can affect high speed
maneuvers in the event of an emergency. The best option is to build sway bar disconnects.
Bumpstops…
You can purchase energy suspension low profile bump stops PN : 99116. I currently have them
installed and was able to net about 1.5” of "uptravel" and have encountered no problems at all.
Make sure you still have tire clearance if you have increased the size of your tires upon full
compression.
Springs...
If you have a stock suspension designed 4x4 S10 you have torsion bars for front springs and the
only "leveling kit" is to adjust your Z-height by tightening the torsion bar adjustment bolt to Z-
spec and then getting an alignment. Your next best option for reaching the top limits of the Z-
spec is the Rough Country kit.
Control arms...
The stock stamped control arms are weak in design and are subject to deformation where the
bushing is pressed through the two vertical pieces of the pivot on the arm. This needs to be
fixed by welding in material to be boxed the pivot and make sure that the arm you are boxing
has not already been deformed. For the upper arm you have a few options. AVOID the Superlift
upper control arm as it is difficult to hold an alignment and has different geometry then the
stock arms. BDS makes tubular upper control arms that are MUCH stronger then stock and
have a different bushing design then the factory setup. Or you can box the upper arm like the
lower arm. The latest option on the market is the Rough country lift kit arms but they also have
different geometry to account for the higher Z- height.
Control arm bushings...
There are also several options for these. You can run stock rubber bushings. You can have
custom delrin bushings made. Or you can run poly bushings. There is a trick to this though.
You will need two kits energy suspension kit PN:33119 and MOOG kit PN: K6418. The energy
suspension kit comes with presleeved lower control arm bushing but not upper bushings. The
upper replacement bushings are prone to accelerated wear in that kit. The Moog kit comes with
presleeved thermoplastic upper control arm bushings. If you are going to use stock control arms
I suggest boxing the arms before you press out the old bushings and install new ones.
Balljoints...
The best choice for the lower control arm is Proforged. They have the highest pullout rating and
hold their strength even when put to the max angle. The upper control arm there two choices:
#1 Stock style balljoints such as Proforged
#2 Fullsize balljoints in the instance that you have Rough Country control arms installed.
Shocks…
The ZR2 came equipped from the factory with Bilstein 5100 shock absorbers and many users have
found that these are an excellent long lasting unit. The Rancho replacement shocks for the S10 are
valved stiffer than the factory shocks.
4x4 but I have identified several ways to get a few inches out of your stock set up.
Rear suspension…
To level your sagging rear suspension on your blazer you can get 2" lift shackles, add-a-leaf,
Monroe air shocks PN:MA764, Deaver replacement leaf packs, or go custom. Lift blocks WILL
NOT WORK as S10's have a spring under axle set-up.
Swaybar…
The basic 4x4 S10 came with a front sway bar. A ZR2 S10 truck came with a front swaybar and
a rear track bar. The blazers came with front and rear swaybars.
I have removed the rear sway bar on every blazer I have owned. Also I have removed my front
swaybar without issue and have had a much more comfortable ride and it handles much better
offroad. DO THIS WITH CAUTION as more body roll is induced and can affect high speed
maneuvers in the event of an emergency. The best option is to build sway bar disconnects.
Bumpstops…
You can purchase energy suspension low profile bump stops PN : 99116. I currently have them
installed and was able to net about 1.5” of "uptravel" and have encountered no problems at all.
Make sure you still have tire clearance if you have increased the size of your tires upon full
compression.
Springs...
If you have a stock suspension designed 4x4 S10 you have torsion bars for front springs and the
only "leveling kit" is to adjust your Z-height by tightening the torsion bar adjustment bolt to Z-
spec and then getting an alignment. Your next best option for reaching the top limits of the Z-
spec is the Rough Country kit.
Control arms...
The stock stamped control arms are weak in design and are subject to deformation where the
bushing is pressed through the two vertical pieces of the pivot on the arm. This needs to be
fixed by welding in material to be boxed the pivot and make sure that the arm you are boxing
has not already been deformed. For the upper arm you have a few options. AVOID the Superlift
upper control arm as it is difficult to hold an alignment and has different geometry then the
stock arms. BDS makes tubular upper control arms that are MUCH stronger then stock and
have a different bushing design then the factory setup. Or you can box the upper arm like the
lower arm. The latest option on the market is the Rough country lift kit arms but they also have
different geometry to account for the higher Z- height.
Control arm bushings...
There are also several options for these. You can run stock rubber bushings. You can have
custom delrin bushings made. Or you can run poly bushings. There is a trick to this though.
You will need two kits energy suspension kit PN:33119 and MOOG kit PN: K6418. The energy
suspension kit comes with presleeved lower control arm bushing but not upper bushings. The
upper replacement bushings are prone to accelerated wear in that kit. The Moog kit comes with
presleeved thermoplastic upper control arm bushings. If you are going to use stock control arms
I suggest boxing the arms before you press out the old bushings and install new ones.
Balljoints...
The best choice for the lower control arm is Proforged. They have the highest pullout rating and
hold their strength even when put to the max angle. The upper control arm there two choices:
#1 Stock style balljoints such as Proforged
#2 Fullsize balljoints in the instance that you have Rough Country control arms installed.
Shocks…
The ZR2 came equipped from the factory with Bilstein 5100 shock absorbers and many users have
found that these are an excellent long lasting unit. The Rancho replacement shocks for the S10 are
valved stiffer than the factory shocks.
Steering
This is another area with many options and a need to decide what your intended use of the vehicle is.
Steering gear box…
The factory steering box can be replaced with a much heavier duty unit from PCS. This will handle the
stress caused by offroad use.
Idler and pitman arm…
These are infamous for failure in S10’s the best option right now is a Proforged or Moog replacement.
Now you have the option of installing a Outfitter Design LLC “1 Ton Idler Arm Adapter” This allows
you to run a idler arm pivot out of a 1 ton silverado and a idler arm out of a K3500.
Steering stabilizer…
ZR2’s came stock with a steering stabilizer and regular S10’s have the option of one. The best
replacement unit is a Ranch PN: RS5401
Tierods…
Replacements from Moog and Proforged are available.
Outfitter Design LLC now sells a HD tierod upgrade package that utilized an outer heim joint, solid
adjuster sleeve, and jam nuts to better retain your alignment. The downside to this is that you cannot
run a front swaybar as the tierods make contact with the swaybar link.
Steering gear box…
The factory steering box can be replaced with a much heavier duty unit from PCS. This will handle the
stress caused by offroad use.
Idler and pitman arm…
These are infamous for failure in S10’s the best option right now is a Proforged or Moog replacement.
Now you have the option of installing a Outfitter Design LLC “1 Ton Idler Arm Adapter” This allows
you to run a idler arm pivot out of a 1 ton silverado and a idler arm out of a K3500.
Steering stabilizer…
ZR2’s came stock with a steering stabilizer and regular S10’s have the option of one. The best
replacement unit is a Ranch PN: RS5401
Tierods…
Replacements from Moog and Proforged are available.
Outfitter Design LLC now sells a HD tierod upgrade package that utilized an outer heim joint, solid
adjuster sleeve, and jam nuts to better retain your alignment. The downside to this is that you cannot
run a front swaybar as the tierods make contact with the swaybar link.
Accessories:
There are many options for an S10 such as lighting, recovery equipment, audio, tires, wheels etc.
Winch…
Currently Boondock sells an armored bumper that can contain a winch through Synergyoffroad. There
used to be a bumper called the Animal Bumper but it is no longer in production. One way to mount
a winch currently is to use the hidden winch mount by Synergy Offroad which mounts the winch
between the frame rails behind the factory bumper. Another option is to use the Warn trans4mer grill
guard.
Wheels…
There are a massive number of wheels for the S10 but here is a guideline the factory wheel for 4x4
S10s is a 15X7” wheel with 6 inches of backspacing and a 5X4.75” bolt pattern.
Winch…
Currently Boondock sells an armored bumper that can contain a winch through Synergyoffroad. There
used to be a bumper called the Animal Bumper but it is no longer in production. One way to mount
a winch currently is to use the hidden winch mount by Synergy Offroad which mounts the winch
between the frame rails behind the factory bumper. Another option is to use the Warn trans4mer grill
guard.
Wheels…
There are a massive number of wheels for the S10 but here is a guideline the factory wheel for 4x4
S10s is a 15X7” wheel with 6 inches of backspacing and a 5X4.75” bolt pattern.
Custom Work:
If you installed Rough Country upper control arms or went custom for the upper control arms and are
willing to do a little fabrication I can give an outline as to what the next step is:
There is a factory bump stop under the upper control arm that limits suspension "droop" or down
travel. Remove the factory bracket that this bumpstop contacts and box the frame. Then remove the
front shocks and torsionbars so that the suspension is free to travel. Measure the compressed length
between the shock mounts and the extended length at full droop before the CV's begin to bind. With
these measurements you can calculate the length shock you need and decide if you can get a shock to
fit in the factory location or you might need to fabricate a shock hoop. A limiting strap needs to also be
installed and its mounts fabricated to protect CV’s and tierods from overextending.
Custom high angle CV’s can be made which would greatly increase results but are usually not
considered due to cost. RCV Performance is a company that has made them for the S10.
willing to do a little fabrication I can give an outline as to what the next step is:
There is a factory bump stop under the upper control arm that limits suspension "droop" or down
travel. Remove the factory bracket that this bumpstop contacts and box the frame. Then remove the
front shocks and torsionbars so that the suspension is free to travel. Measure the compressed length
between the shock mounts and the extended length at full droop before the CV's begin to bind. With
these measurements you can calculate the length shock you need and decide if you can get a shock to
fit in the factory location or you might need to fabricate a shock hoop. A limiting strap needs to also be
installed and its mounts fabricated to protect CV’s and tierods from overextending.
Custom high angle CV’s can be made which would greatly increase results but are usually not
considered due to cost. RCV Performance is a company that has made them for the S10.
Where to buy S10 Accessories:
There are several places where I have found parts needed to build the above “Ultimate IFS S10” such
as:
Synergy Offroad (http://www.shop.synergyoffroad.com),
Junkyard search (car-part.com),
RCV Performance (http://www.rcvperformance.com)
as:
Synergy Offroad (http://www.shop.synergyoffroad.com),
Junkyard search (car-part.com),
RCV Performance (http://www.rcvperformance.com)
