Do I have have enough Truck?
Hello All, My first post and good to meet you all. we're getting back into RV and traveling. Have an important question regarding towing heavy fifth wheel. We picked up a 04' Keystone Spri...
Forum Discussion
Welcome to the forum !
Mine is a 1996 K3500, 7.4L Suburban with 4.1’s. Upgraded brakes to be similar to yours. Only thing not upgraded to like yours is the front disc & friction material (not as thick, but swept area is about the same).
Am not going to comment on a fiver, as don’t have much experience with them. Just played around with them helping church members figure out their issues.
First, our rear axles are from AAM and AAM rates it at 10,000 GAWR. GM rates ours at 6K GAWR. Don’t know whether spring pack, brakes, or ??? Dodge of same era also uses that same AAM axle.
Brakes on GMT400 in stock form is barely okay when up to snuf. Can be made to be very good to GREAT. Dodge of same ear also used similar front brakes and also had problems.
Main issue is the caliper slide assembly, over time, stick. Key to knowing that is to check if one side friction material is wearing out faster than the opposite side. What happens is that the caliper assembly sticks and locks one side so it is misaligned. (Edit…had to change to ‘locks’…bad word filter forbid he word initially used)
Solution is to super tune the caliper slide assembly, if you haven’t yet.
Get OEM rebuild kit and be sure to use the new O-rings. Tough to get them installed and know many who just give up and toss them.
I use Sta-Lube high temp brake grease that has a high amount of Molybdenum Sulfide pre-mixed. Mix it with Mobil 1 to reduce the viscosity a bit.
Generously coat the O-Rings and the slide bore/tube with above grease.
Poke in the slide tube and almost poked out the other side. Almost, so as to allow filling that cavity between the tube and cast iron bore. Leave some air, as too much will have it expand and leak.
Then assemble as per manual and use the highest performance (hardest) friction material you can find. They will make much more noise, but that is the way of performance friction material. Doesn’t bother me, as know I have nose bleed brakes…have out stopped a sedan where they just barely rear ended me.
The G80 locker is a clutch type from Eaten. Ours has a governor set too high before it tosses in that clutch to lock. Newer governor is set at around 200 RPM differential. Older will lock with too much differential (and much more power) RPMs and grenades the diff.
1995 has the thermal safety set higher than mine and will go into the various limp modes too soon. Buddy removed the main thermo set point on his 1995 K3500 Suburban and it be got both higher MPG & stay longer in power mode. Along with a 180*F thermostat (mine too) get power mode most times when nailing the throttle.
Don’t know what your tuner will do with the Cummins & Allison, but they should know all that.
Designed a AFT aux cooler mounted midship for him. on my list, but haven’t done it yet.
Two 45,000 lb rated plate ATF coolers with an electric radiator fan. Didn’t put in a bypass valve and just made sure the ATF also ran into & through the main radiator.
His dash coolant temp gauge drop like a rock when that external ATF cooler’s fans turned on.
He towed an approx 10,000 lb trailer.
Assume you have heard of the DuraBurb with a Duramax diesel/Alison combo. Should be lots of info that applies to your planned Cummins/Alison combo.
Good luck and report back on this thread !
Mine is a 1996 K3500, 7.4L Suburban with 4.1’s. Upgraded brakes to be similar to yours. Only thing not upgraded to like yours is the front disc & friction material (not as thick, but swept area is about the same).
Am not going to comment on a fiver, as don’t have much experience with them. Just played around with them helping church members figure out their issues.
First, our rear axles are from AAM and AAM rates it at 10,000 GAWR. GM rates ours at 6K GAWR. Don’t know whether spring pack, brakes, or ??? Dodge of same era also uses that same AAM axle.
Brakes on GMT400 in stock form is barely okay when up to snuf. Can be made to be very good to GREAT. Dodge of same ear also used similar front brakes and also had problems.
Main issue is the caliper slide assembly, over time, stick. Key to knowing that is to check if one side friction material is wearing out faster than the opposite side. What happens is that the caliper assembly sticks and locks one side so it is misaligned. (Edit…had to change to ‘locks’…bad word filter forbid he word initially used)
Solution is to super tune the caliper slide assembly, if you haven’t yet.
Get OEM rebuild kit and be sure to use the new O-rings. Tough to get them installed and know many who just give up and toss them.
I use Sta-Lube high temp brake grease that has a high amount of Molybdenum Sulfide pre-mixed. Mix it with Mobil 1 to reduce the viscosity a bit.
Generously coat the O-Rings and the slide bore/tube with above grease.
Poke in the slide tube and almost poked out the other side. Almost, so as to allow filling that cavity between the tube and cast iron bore. Leave some air, as too much will have it expand and leak.
Then assemble as per manual and use the highest performance (hardest) friction material you can find. They will make much more noise, but that is the way of performance friction material. Doesn’t bother me, as know I have nose bleed brakes…have out stopped a sedan where they just barely rear ended me.
The G80 locker is a clutch type from Eaten. Ours has a governor set too high before it tosses in that clutch to lock. Newer governor is set at around 200 RPM differential. Older will lock with too much differential (and much more power) RPMs and grenades the diff.
1995 has the thermal safety set higher than mine and will go into the various limp modes too soon. Buddy removed the main thermo set point on his 1995 K3500 Suburban and it be got both higher MPG & stay longer in power mode. Along with a 180*F thermostat (mine too) get power mode most times when nailing the throttle.
Don’t know what your tuner will do with the Cummins & Allison, but they should know all that.
Designed a AFT aux cooler mounted midship for him. on my list, but haven’t done it yet.
Two 45,000 lb rated plate ATF coolers with an electric radiator fan. Didn’t put in a bypass valve and just made sure the ATF also ran into & through the main radiator.
His dash coolant temp gauge drop like a rock when that external ATF cooler’s fans turned on.
He towed an approx 10,000 lb trailer.
Assume you have heard of the DuraBurb with a Duramax diesel/Alison combo. Should be lots of info that applies to your planned Cummins/Alison combo.
Good luck and report back on this thread !
