2001 GMC Sierra 2500 - Answered Questions & Fixed issues

Hello. It seems there is an electrical 'break' between the electrical jack of your truck and trailer. This could be the jack itself or a broken wire(s) of the trailer. Good luck and keep me informed; if you want to.

You need to check for fault codes, the check engine light is on because a fault is in the system. Here is how to do a fault code test, no special tools required. Follow the link please. FAQ How to read older GM codes for free

If you look at the upper radiator hose just beside it is a switch that looks like a temp switch (but it is not a temp switch) the switch sends a signal to the computer to mix the fuel. I would change it and see if rough running goes away. The timing is probably ok.

The seal can be changed. You will need to remove pitman arm and remove clip that holds in pitman arm seals. Once clip is removed put a bucket under it and start truck, turn and hold wheel all the way one way and seal will pop out. When installing new one first put some Vaseline on it so you don't tear it on the install. This is also a good time to change your fluid

You more likely have an internal problem, namely the High-Reverse clutch pack. If the trans is making the 1 - 2 shift, and your Service Engine light is not on then your speed sensors are working. Judging by the age of the vehicle I would guess that the trans has already been rebuilt at least once (most of the overhauls I do occur at about 150,000 kms) and the failure I see most is the sealing rings have scored the direct drum and led to no third and/or reverse, and of course, no third, no fourth. Want a quick and easy check? Pull the trans dipstick and smell the fluid. It likely has a burnt smell to it.

Is the EGR leaking maybe? Is the idle speed motor working alright?

the syncro rings are poss worn

Tail lights or brake lights?

Transmission stuck in 3rd gear,your transmission might be going out of your truck. ----------------------------------------------------------------------------------Renault CAN Clip V124

get a 20 dollar haynes or chiltons manuel and find the module and coil. always change the ignition module and coil every 4 no more than -5 years to be safe.

Not a transmission expert, but you say you rebuilt it yourself ? What was the original problem ?It could be a blocked valve body or clutch problem, maybe a solenoid.You are bypassing first gear by starting in second, so whatever it takes to make first gear engage is not happening.

not a lot of info mate...what I can tell you is that in some vehicles Jackaroo for example..you have to reverse a little to unlock once you disengage the 4WD..

I would start with the fuses,Check under the dash in the fuse box. Make sure all fuses are good. If there is a blown fuse then replace it, If the fuse blows then you may have a short in the wiring to tail lights, also check wire connections at the rear bumper area.I have seen the connector go bad, test power going into and coming out of connector to tail lights. if there is a trailer hitch on this truck then check where the hitch wiring was connected , check for bad connections.If the front park lights work then it may not be the light switch but rather a bad wire.Here is a wiring diagram to help you.have a good day and i hope this is helpful. If there is something else i can help with please let me know.

Blue is usely valves black is usely rings . But one effects the other a good rule is when you see oil pushing up to the air intake area then its likely rings but valves go first and can be repaired with a valve job . Check the cylinders with a compressition gauge they should be with in 15% of each other.But then again it could be the valve guide seals that seal the valve steams . So pull the plugs and do a compressition check on the engine . This will give you a better veiw on what needs to be done with out wasteing time and money look for oil up to high and change the PCV FIRST
















Blue smoke

Do you have any service engine light on? If yes, then you need to get the code(s). Auto Zone, and maybe others, will hook up a code reader for free.
The up stream and down stream O2 sensors in vehicles today monitor the Catalytic Convertors. O2's being bad usually do not cause a poor running condition. At least not what you described.

The alternator output is regulated by the ECM (electronic control module). Check the wiring between the alternator field circuit and the ECM; if the wire and connectors ar4e okay you MAY need to replace the ECM.

Purchased a new gray Standyne Fuel Solenoid Driver kit with heat sink and extended wire harness. Mounted on left fender well and was able to do the work myself in about an hour. No need for injector pump work. Solved stalling issues and it starts up easier as well. These are all over ebay. Very common issue with this engine, and the GMC knuckleheads knew about it and didn't do anything to educate dealerships on a permanant fix.

do the front marker/park lights work if not you could have a bad light switch on the tail light side of the switch.you need to check the brown wire at the back of the truck in the wiring harness as this is the tail light wire that feeds the bulbs.if you have power there then you will have to check for power at the socket,if no power at the socket but were you check the wire then there is a problem between the two that you will have to check out.if there is no power when checking the wire then you will have to check for lose of power between the switch and rear wiring.make sure the fuse is good by using a test light and not by looking as sometimes they look good but don`t work.