1988 Chevy 4X4 front differential won't lock up !! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69Chevyc10 · 04-20-2003, 11:39 AM

I have a 1988 Chevy 4X4 and the front differential won't lock up.
The transfer case shifts into 4 hi and 4 lo fine its just that the auto hubs wont lock the driveshafts up front. The front driveshaft spins, just no power transfered to the wheels, it just free spins.
any suggestions would be appreciated.
Thanks

sakohntr · 04-20-2003, 02:02 PM

If you have the front independant suspension, more than likely your thermal actuator is bad. This is common. You can verify this by checking to see if you have voltage going to the front dif where this actuator screws into the side of the pumpkin. There is also an aftermarket version available that is manual, whereby you pull a cable that slides a plunger which replaces the original electric actuator. It is called posi-lok. The 88-93's were slow in engaging. They then went to a hi speed actuator after that. good luck

04-20-2003, 11:39 AM	#1
69Chevyc10 Registered User Join Date: Mar 2002 Location: ND USA Posts: 122	1988 Chevy 4X4 front differential won't lock up !! I have a 1988 Chevy 4X4 and the front differential won't lock up. The transfer case shifts into 4 hi and 4 lo fine its just that the auto hubs wont lock the driveshafts up front. The front driveshaft spins, just no power transfered to the wheels, it just free spins. any suggestions would be appreciated. Thanks

04-20-2003, 02:02 PM	#2
sakohntr Registered User Join Date: Mar 2002 Location: Floodwood Minnesota Posts: 1,057	front If you have the front independant suspension, more than likely your thermal actuator is bad. This is common. You can verify this by checking to see if you have voltage going to the front dif where this actuator screws into the side of the pumpkin. There is also an aftermarket version available that is manual, whereby you pull a cable that slides a plunger which replaces the original electric actuator. It is called posi-lok. The 88-93's were slow in engaging. They then went to a hi speed actuator after that. good luck __________________ 1967 K30 Napco 292/SM420 original paint 30k miles 1968 K60 Napco 396/5spd. dbl frame 52" michelins 1969 K10 SWB GMC 454/4spd 6" 35's posi,hooks 1972 C30 longhorn,BB/AT,A/C,Tilt,Toolbox,lokr 1987 K20 Chevrolet Suburban. 6" lift. 5.7L/TH400 1979 K60 GMC Coleman 4x4, 427/Allison.



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