4wheel drive problem

Asked by Feb 09, 2014 at 11:01 AM about the 1994 GMC Sierra 2500

Question type: Maintenance & Repair

I have a problem with my 4wheeldrive not
engaging at the front axil. The transfercase is
working. I know there is an actuator but im
wondering if there is a problem caused by the
previous owner modification to the heater
system. There is a manual shutoff valve
installed in the hotwater hose. Also there is a
30amp fuse in the 4x4 fuse socket. The lable on
the fuse box says 25amp. Anyway, any thougt
as to what I should search for

1 Answer


The '94 has the thermal actuator in the front end. They are slow and they do fail. It probably kept poping the fuse while it was on it's last leg. The last one I bough was about $180 bucks. They are very easy to change and thats were I would start. I think a 15" cresent wrench fits on it. Just un-plug and thread out. If your on level ground the front diff fluid should not leak out. You can pull and test the old one to see if its the problem before you buy a new one. You never know if there is wiring damage. I use a fuse holder. I strip both ends, twist and tin them (cover them with solder so they are like a probe) do it to a scrap wire also. The plug should only have 2 pins. Cannot remember the colors. Would assume the black is ground. Use a 20/5 amp fuse and probe the + and - from your battery. It will S......L.....O......W.....L....Y extend if it's good. Takes 8 to 20 seconds usually. If it doesn't move replace. Dielectric grease in the elec connectors on re assembly helps keep the moisture out.

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

  • Transmission problems 3 answers

    I have a 2002 GMC Sierra 2500 and before i bought it from a buddy he drove it through a very large puddle and it cracked his block. So we replaced the engine and then the tranny started giving hi...

    2002 GMC Sierra 2500 4 Dr SL 4WD Extended Cab SB


    Maintenance & Repair

  • My 4 wheel drive stopped working 2 answers

    After struggling with the 4 wheel drive it stopped working. The last two winters the 4 wheel got cranky. If you shifted it in and out of gear it would engage, sometimes in low sometimes in high, now i...

    1990 GMC Sierra 2500


    Maintenance & Repair

  • 95 GMC Pick Up 2500 Sierra SLE Extended Cab 1 answer

    While driving city streets my truck develops front end shaking or bouncing. When I slow down it stops. Feels like it is coming from drivers side wheel. Thought it might be tire balance problem. Rotat...

    1995 GMC Sierra 2500 2 Dr C2500 SLE Extended Cab SB


    Maintenance & Repair

  • 1995 GMC Sierra 2500 cuts off 5 answers

    My Sierra cut off on me to work (fuel issue). Changed the fuel filter first, nothing. Then changed the fuel pump (worked). Cranked fine, no issues. Immediately drove to gas station (approx 2 miles),...

    1995 GMC Sierra 2500 2 Dr C2500 SLT Extended Cab LB HD


    Maintenance & Repair

  • what kind of manual transmission can i u that will bolt up to my block? 1 answer

    i am trying to put a 1970s model bow tie block in a 2000 gmc with a manual transmission with a 2.5 transfer case. my problem is the transmission is to short. what kind of manual transmission can i u...

    2000 GMC Sierra 2500 2 Dr SL Standard Cab LB


    Car Customization

Search GMC Sierra 2500 Questions

GMC Sierra 2500 Experts

#1 Rowefast
Reputation 150
#2 FordNut
Reputation 100
#3 tennisshoes
Reputation 70
View All

Related Models For Sale

Used GMC Sierra 1500"
1,023 Great Deals out of 56,283 listings starting at $2,499
Used Dodge Ram 2500"
153 Great Deals out of 5,734 listings starting at $2,289
Used Ford F-250"
603 listings starting at $3,995
Used Ford F-150"
3,174 Great Deals out of 216,366 listings starting at $1,900
Used GMC Sierra 3500"
8 Great Deals out of 302 listings starting at $5,495
Used Chevrolet C/K 2500"
279 listings starting at $1,995
Used Dodge Ram 1500"
513 Great Deals out of 13,809 listings starting at $995

Used Cars For Sale

2004 GMC Sierra 2500 For Sale
46 listings starting at $9,500
2001 GMC Sierra 2500 For Sale
8 listings starting at $4,950
2000 GMC Sierra 2500 For Sale
35 listings starting at $5,414