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4wd front differential

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ratchetgmc

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gloucester,va
when placing in 4wd front differential feels like something dragging or not smooth when driving. front driveshaft turning. when shift back to 2wd everthing back to normal. pulled front diff plug to check fluid level after trying a couple of times. looked like chocolate milk. help; this is out of my range of knowledge. 89 fullsize.
 
truck all stock. but good guess; that is exactly what it feels like; only not as noticable as this would feel . thank you for your response.
 
Are you in dirt? If you are on the street it will drag like crazy.
 
One problem for sure is the "chocolate milk" gear lube. There is water in your gear oil.. :eek1: You need to drain the diff completely, wipe it out as much as possible with rags, then clean it good with a can of aerosol brake cleaner. Once it's all clean inside, re-install the cover and fill the diff will new gear lube.
 
HarryH3 said:
One problem for sure is the "chocolate milk" gear lube. There is water in your gear oil.. :eek1: You need to drain the diff completely, wipe it out as much as possible with rags, then clean it good with a can of aerosol brake cleaner. Once it's all clean inside, re-install the cover and fill the diff will new gear lube.
Click to expand...

DO THIS NOW!! I was always told, and have done, that if your gear oil is milky to change it right away, then put it in 4wd to get the oil to move around then change it again. This enables you to make sure you got all the old milky stuff out.

Dustin
 
does anyone know if the water in the gear oil could actually be felt when driving; this is hard for me to believe but i really do not know.
 
you prob wont feel the water but you will feel rusted/seized/spun bearings, maybe even rust on the ring and pinion causing interference

does your housing/seals leak? have you swamped your axle lately, or in the last few mo's?

if fluid leaks out, water can get in. and check your vent tube too

it could also be your joints check/grease them too

do your brakes drag?
 
thank you gambit420s for your help. i need to take some time out of my busy schedule to join this site. this work is to put this blazer up for sale. bought 6 months ago for my wife to drive but have since came across a deal i could not refuse (because my wife told me so). never really drove blazer. nice truck fairly well maintained but i also have a 91 suburban that i have had for years and can`t part with. as for your reply; you may be right on time. would appreciate any more ideas but i have some time off in a few days and i will pull cover to inspect and install fresh gear oil.thanks again for taking time out of your day to help me gambit420s men like yourself is what makes these forums happen.
 
thank you for your reply gambit420s.need to take a few minutes out of my busy life to join this site. the work i am doing to this blazer is getting it ready to sell. nice truck that i bought 6 months ago for my wife to drive but have since found a great deal that i could not refuse (because my wife told me so).so now have way too many vehicles and will part with. will join site because i also have another blazer and a suburban that i can`t part with. gambit420s, men like yourself taking time out for others i what makes these sites work. i will post to help others. sorry for the dual reply;thought the first reply did not get submitted.
 
Oil that has water in it is called "emulsified" and basically loses nearly all its lubrication properties. It also turns to a thickened sludge as it gets whipped up by mechanical forces (spinning gears, moving pistons, etc.). This could very easily cause great drag on the axle. I had an engine that blew a head gasket and imulsified the oil, you had to go heavy on the throttle to get it to overcome the drag (No, I didn't run it like this, I just had to get it home a couple miles). The oil change is the first thing to try, if that doesn't work you know that some bearing surface is not doing its job.

To do a test to help isolate the problem, support the front axle on jackstands. With the transfercase in 4wd rotate one tire (the other should spin opposite). This will test the spindle, hub, and spider gears for the drag, because the transfer case will hold the driveshaft still. If it rolls easy, put it in 2wd, and put one wheel back on the ground. Rotate the raised wheel again, which will isolate the pinion, carrier and transfercase output bearings. If you get some resistance here, disconnect the front driveshaft and you will be able to tell if its in the pinion/carrier or in the transfercase output.

Hope this helps.
 
guiddo666; you are the man. this helps very much. i think this info is better than the shop manuals. your explaination of the results of emulsified oil was right on the money and just what i was looking for; makes since. when i removed a sample of the oil just after running in 4wd for a couple of hundred feet it looked much like a chocolate milk shake (as opposed to my description of chocolate milk). after my drain,clean and refill. i will try your test step by step to attempt to isolate.thanks again guys.
 
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