Front differential won't disengage - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bad71gmc · 03-06-2004, 09:53 PM

I have a '88 k1500 pickup and I was having trouble with the acuator activating and the last time it did engage and I went to take out of 4x4 the indcator still shows the front axle locked up and indeed it is still engaged.
I have tried driving it in 2 hi and shifting back and forth between 2 and 4 wheel drive and it will not disengage.
If the acuator is bad could it keep the differential locked up??
also if the acuator is removed should it disengage the front axle??
Thanks for the help!!

Scrub · 03-07-2004, 01:22 AM

I'm not real knowledgeable about the newer systems, but as far as I know, the actuator is an electric solenoid that depresses the locking actuator. Removing it should cause the rig to drop into 2wd. Kind of wierd that it is stuck that way.

Good Luck

75-K5 · 03-07-2004, 06:26 AM

Try putting it in 2wd and driving in reverse for several feet. That might help the automatic lockouts disengage.

bad71gmc · 03-07-2004, 09:32 PM

I got the axle disengaged, but when I pulled the acuator out it had a dirt film on it and I think that the inside of the differential is the same and it caused the collar that locks the axle to not slide as it should.Does anyone know of a additive that I could put in the fluid to clean the inside of the differential out as it has no cover that can be removed to clean it out. If I could clean it out and put in fresh gear oil I believe that my problem would be solved.
So any sugesstions on an additive that would clean it out??
Thanks

DivineFord · 03-07-2004, 11:09 PM

drain the fluid in the front diff and then refill it up to the fill hole with fresh fluid. Then take is out on a dirt road, parking lot, or anywhere where you can play easy with the four wheel drive. Then drive in the dirt letting it engage and then let it go into two wheel drive. Do this untill it loosens up. When it works okay (hopefully this will lube it up enough to work properly) then drain the fluid out of the diff again, and maybe pour some fresh fluid through to wash out any crap in there. Then fill with fresh fluid and hopefully it will work properly. These front diffs tend to leak fluid at the cv shafts, and the level doesn't get checked by many owners or shops. I had one just like yours in the shop last year and it took some coaxing to get out of 4wd. I checked the fluid and it was almost dry. Filling up the fluid helped it out. If this doesn't work, the front diff may need to be pulled apart and checked. Let me know how this all works out.

olblue60@aol.com · 03-09-2004, 09:48 AM

I'm just working through the same problem in my 1996.The info that "devine" is giving you is the route that I am taking. My truck was even sounding tight and a low wine was audible. I have so far flushed out twice and am now running a sinthetic lube.The noise has left and the system is now functiuoning pretty well.The mechanic told me that the truck may never get to where it will disengage without backing up but It is noticably better.He also said that during rainy periods, ingage the 4WD ocasionaly,when driving on fairly straight roads, throughout the year to keep it exercised. I replaced the acuator too. It didnt seem to help.The original GMs were weak but the transfer case as you said is disengaging as your switch says, just not the front rear. Good luck

John

03-06-2004, 09:53 PM	#1
bad71gmc Registered User Join Date: May 2002 Posts: 71	Front differential won't disengage I have a '88 k1500 pickup and I was having trouble with the acuator activating and the last time it did engage and I went to take out of 4x4 the indcator still shows the front axle locked up and indeed it is still engaged. I have tried driving it in 2 hi and shifting back and forth between 2 and 4 wheel drive and it will not disengage. If the acuator is bad could it keep the differential locked up?? also if the acuator is removed should it disengage the front axle?? Thanks for the help!!

03-07-2004, 01:22 AM	#2
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	I'm not real knowledgeable about the newer systems, but as far as I know, the actuator is an electric solenoid that depresses the locking actuator. Removing it should cause the rig to drop into 2wd. Kind of wierd that it is stuck that way. Good Luck __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

03-07-2004, 06:26 AM	#3
75-K5 Bucket of Bolts Join Date: Dec 2003 Location: Anderson, Indiana Posts: 455	Try putting it in 2wd and driving in reverse for several feet. That might help the automatic lockouts disengage. __________________ This is the project that never ends, yes it goes on and on my friend....

03-09-2004, 09:48 AM	#6
olblue60@aol.com member Join Date: Dec 2003 Location: Silver Spring Md.20901 Posts: 2,031	4wd I'm just working through the same problem in my 1996.The info that "devine" is giving you is the route that I am taking. My truck was even sounding tight and a low wine was audible. I have so far flushed out twice and am now running a sinthetic lube.The noise has left and the system is now functiuoning pretty well.The mechanic told me that the truck may never get to where it will disengage without backing up but It is noticably better.He also said that during rainy periods, ingage the 4WD ocasionaly,when driving on fairly straight roads, throughout the year to keep it exercised. I replaced the acuator too. It didnt seem to help.The original GMs were weak but the transfer case as you said is disengaging as your switch says, just not the front rear. Good luck John __________________ 1967 C/K10 Chevy Panel 1968 C/K20 Chevy Pickup 1968 C/K10 Chevy Suburban 1941 Chevy Sedan Delivery 1960 Chevy Sedan Delivery 1972 Camaro SS 396 #s matching 1971 Harley FX Superglide

03-07-2004, 09:32 PM	#4
bad71gmc Registered User Join Date: May 2002 Posts: 71	I got the axle disengaged, but when I pulled the acuator out it had a dirt film on it and I think that the inside of the differential is the same and it caused the collar that locks the axle to not slide as it should.Does anyone know of a additive that I could put in the fluid to clean the inside of the differential out as it has no cover that can be removed to clean it out. If I could clean it out and put in fresh gear oil I believe that my problem would be solved. So any sugesstions on an additive that would clean it out?? Thanks

03-07-2004, 11:09 PM	#5
DivineFord My Name Is Mudd Join Date: Feb 2004 Location: Bangor, Maine Posts: 101	drain the fluid in the front diff and then refill it up to the fill hole with fresh fluid. Then take is out on a dirt road, parking lot, or anywhere where you can play easy with the four wheel drive. Then drive in the dirt letting it engage and then let it go into two wheel drive. Do this untill it loosens up. When it works okay (hopefully this will lube it up enough to work properly) then drain the fluid out of the diff again, and maybe pour some fresh fluid through to wash out any crap in there. Then fill with fresh fluid and hopefully it will work properly. These front diffs tend to leak fluid at the cv shafts, and the level doesn't get checked by many owners or shops. I had one just like yours in the shop last year and it took some coaxing to get out of 4wd. I checked the fluid and it was almost dry. Filling up the fluid helped it out. If this doesn't work, the front diff may need to be pulled apart and checked. Let me know how this all works out.



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