Small Block 400 Overheating in 4wd

[johnhood]

What would cause my Engine to overheat when the truck is in 4wd only??? ive had it for around two months now and every time i lock it in 4wd the temp runs around 230 but in two it runs 180-190???

Its only a smallblock 400 it was all factory when i got the truck just a towing cam i put a eldelbrock high rise intake and holley carb i called the guy i bought it from he says it ran hot with him in only 4wd any suggestions???

Thanks,
John

[bake74]

     One of your other post I answered you said your front driveshaft splines were stripped, now this post is making me curious about your gearing. 
     Have you popped open the front and rear diff's and actually checked your ring and pinion gears to see if the are the same ?  All your problems you are posting about makes me believe you do not have the same front and rear gears.
     To answer this question ( and your stripped splines ), if your front gears were different, the truck would work extra hard trying to force the axles to go at the same speed in 4x4.  ( which in turn may have caused some of your other problems ).

[johnhood]

ok now im really wondering i was told that they were the same, i have planned on servicing the front and rear end where would i find the ratio on the ring and pinion?

[johnhood]

but there is one thing i has done it without the hub actually being locked in.

[zieg85]

ok now im really wondering i was told that they were the same, i have planned on servicing the front and rear end where would i find the ratio on the ring and pinion?

The numbers are stamped on the ring gear.  40/13 for example is a 3.07

[bake74]

ok now im really wondering i was told that they were the same, i have planned on servicing the front and rear end where would i find the ratio on the ring and pinion?

     You count the ring gear teeth and divide the pinion gear teeth into the ring gear to get the ratio.

but there is one thing i has done it without the hub actually being locked in.

     The hubs only lock in the axles for the front tires, if you engaged transfer case, the ring and pinion is still turning.

[johnhood]

true i did forget did realize after gettin the truck that the driveshaft was loose from the transfer case which the other day i was running the truck 4wd with everything oprating fine then a loud pop came from the front end then it overheated real bad thats when i noticed the front driveshaft splines had stripped but in other words all of the front end can be loose and it still go over 230 degrees in temp im starting to wonder if its in the transfer case?

[johnhood]

the engine is bored not sure of how much i do realize that it bieng bored will have alot to do with it overheating im planning on gettin head work done when i get the money up i will see how much it is bored then

[jaredts]

ok now im really wondering i was told that they were the same, i have planned on servicing the front and rear end where would i find the ratio on the ring and pinion?

     You count the ring gear teeth and divide the pinion gear teeth into the ring gear to get the ratio.

but there is one thing i has done it without the hub actually being locked in.

     The hubs only lock in the axles for the front tires, if you engaged transfer case, the ring and pinion is still turning.

The ring and pinion still turn, but if the hubs are unlocked why would it matter what speed they turn in reference to the rear?

[bake74]

ok now im really wondering i was told that they were the same, i have planned on servicing the front and rear end where would i find the ratio on the ring and pinion?

     You count the ring gear teeth and divide the pinion gear teeth into the ring gear to get the ratio.

but there is one thing i has done it without the hub actually being locked in.

     The hubs only lock in the axles for the front tires, if you engaged transfer case, the ring and pinion is still turning.

The ring and pinion still turn, but if the hubs are unlocked why would it matter what speed they turn in reference to the rear?

     Your right, that would not matter, only if the hubs are locked in, missed that one little detail.  But for some reason while in 4wd the engine is having to work harder to push the vehicle, therefor only overheating in 4wd. 
     I would look into the transfer case next.

[johnhood]

i have a 350 that ive thought about stickin in their to see if it overheats too but i also believe that its in the transfer case

[firefighter]

I wonder how it would work to jack up and support all 4 corners of the truck suspension, start the truck and put it in 4WD and see how freely everything begins to rotate.
A guy sure hates to begin a major drivetrain disassembly, only to find out it was something else.
It's just odd that the 4WD mechanism would turn so hard that it would make the motor overheat. If it is something in the transfer case, it must be turning really, really hard.
I'll be very interested to find out the end result of this problem.

[johnhood]

i will let everyone know what it is and thats a good idea ill try that before i start to tear down the drivetrain

[BIG CHEVY]

Maybe it just does it in low range because you arent forcing air in the nose.

[johnhood]

it does it in high range too you could be right but it has an electric fan setup