gto0188

Scored some factory alloys off same year truck. The tires currently on my steel wheels are less than 1 year old and I'd like to use them. They are 245/75-16. The alloys I got have 265/75-16 tires which are junk. Will there be an issue mounting the 245s on the alloy wheels?

Mehh... have a 86 k10 and 79 w200 both with original steel wheels and both dedicated plow trucks past 15 years. No rust thru on the wheels.

I have owned several older vehicles to include some real clunkers... much older than my 01' Sierra. Never experienced a rotted out wheel. Noticed a slow leak at LF tire. Upon inspection I found it seeping from the inner part of the wheel. All the other wheels aren't far behind. I am glad it started leaking before the wheel completely failed so I can replace all wheels with alloy wheels of same vintage. These wheels are weak and dangerous. Design flaw as I see it since everything collects in that pocket. If you have GM steel wheels GMT800 vintage and live in the rust belt inspect them!

It ended up being the fuel tank pressure sensor. I was barely able to replace it by moving the driveshaft out of the way to get my hands up there and work by feel.

Thanks very much for the info FriendlyMan. Looks like I may be headed down a similar path... I was excited since after I put the new fuel cap on the SES light stayed off for awhile. Came back on today. I crawled under the truck expecting to see a round vent solenoid but nope, mine is the rectangular style above the fuel tank between the cab and bed. Only way to access it is bed removal ugh. Mine is this style shown below: Been planning on doing much needed corrosion control anyway and now would be a good time to do it. I will replace the vent solenoid AND the fuel tank pressure switch since that too is on top of the tank. Before all that I will go ahead and put a new purge solenoid in. Easy enough right on top of the engine. Man crap like this makes me miss my 77' K10!

2001 Sierra 1500 Ext Cab 4.8 4wd 135,000 miles. Throwing a P0446 Evap Code. Cleared code tried just retightening gas cap. No luck light back on. From what I gather there are several causes of this code to include: 1. Gas Cap 2. EVAP Canister Solenoid Vent Valve 3. EVAP Canister Purge Valve 4. Tank Pressure Switch Also any faulty wiring/hoses to these components. I do not have access to an expensive scanner that will test functionality of these components. I hate blindly throwing parts at something but I'm a bit blind here without the use of a scanner. Is there a pretty common part that causes P0446? My plan of attack is based on easiest-hardest to access parts. 1. New Gas Cap 2. New Canister Purge Valve 3. New Canister Vent Valve 4. New pressure switch (looks like bed will need to be removed for this although I did find some Youtube videos where they were able to replace w/o removal). What have you found to be the common faulty part with P0446?

Scanned it today. Code C0374 - General System Malfunction After 10 or more consecutive slips are uncorrected, this code is activated. Says if transfer case is shifting normally... which mine is.... problem may be internal. The burnt fluid doesnt lie. Sounds like I need a new T case.

Thanks starman8tdc I am going to revisit this... the encoder that is. Based on some further research I gathered, *usually* if there is something wacky going on with the encoder, the drive selections will not be successful which would be noted by blinking selector lights and failure to go into the selected mode. However, I did read a few cases where all *seems* OK on the indictator... such as in my case.... where the encoder motor makes the audible noises during selection followed by a nice solid indicator light. BUT, the encoder motor isn’t holding in the clutches therefore it isn’t actually engaged. Going to do the very test you just mentioned by jacking up the front. I also have access to what seems to be a pretty elaborate Snap On scanner. Not sure if it will read GM 4wd codes but I will give it a shot. As mentioned, when the issue first started, the “Service 4wd System” light came on. It never returned but I’d love to see what the code was.

Thanks starman8tdc I am going to revisit this... the encoder that is. Based on some further research I gathered, *usually* if there is something wacky going on with the encoder, the drive selections will not be successful which would be noted by blinking selector lights and failure to go into the selected mode. However, I did read a few cases where all *seems* OK on the indictator... such as in my case.... where the encoder motor makes the audible noises during selection followed by a nice solid indicator light. BUT, the encoder motor isn’t holding in the clutches therefore it isn’t actually engaged. Going to do the very test you just mentioned by jacking up the front. I also have access to what seems to be a pretty elaborate Snap On scanner. Not sure if it will read GM 4wd codes but I will give it a shot. As mentioned, when the issue first started, the “Service 4wd System” light came on. It never returned but I’d love to see what the code was.

Has not been converted. As mentioned, with the front wheels off the ground and in 2hi, the wheels are independent from one another (spinning one wheel has zero effect on the other). Once I engage any of the 4x4 selections and I spin a front wheel, the other wheel spins opposite of it. That tells me the front diff is certainly engaging.

2001 GMC Sierra SLE 4x4 4.8. It has the push button 4x4 setup with Auto 4wd. Owned the truck almost a year. 125,000 miles. 4x4 worked great last winter. Not working this year. Couple days ago during snowstorm I selected AUTO 4wd and was about to start my journey. Truck was slippin and sliding and clearly not in 4wd. Just as I started to recognize the condition, the Service 4wd System light came on. I pulled over to a side road. Shut the truck off and restarted. Service 4wd light went away and this time I selected 4 HI. Still not working in 4hi even though the light is illuminated on 4hi. Ok great. This time I try 4 LO. Light is illuminated on 4 LO and the truck is clearly in low range because the truck is much slower but torquier. BUT, still no traction, front wheels not engaging. I can hear the transfer case doing its motor thing and engaging between all the 2wd and 4wd options. I removed the front diff actuator and that is functioning fine (retracting and moving). I decided to put a new one in (Dorman) after removing the original because the plastic threads got kinda messed up. Still no 4wd. I jack up the front of the truck. In 2hi each front wheel is independent from one another. I engage any of the 4wd options and yup, the diff is definitely engaging because now the front wheels react to one another when the truck is jacked up. I had a friend carefully drive the truck while I observed the front drive shaft. It spins although I also notice it spins in 2wd so not sure if thats a good test. All 4 wheels on the ground if it’s in 2wd I can spin the front driveshaft. In the 4hi and lo modes it definitely locks in. Ok on to the transfer case fluid. Drained it out. Black and BURNT like real burnt stunk up my garage. I replaced with new Auto Trak II and tried to cycle thru the modes a few times and drive. Still no 4x4. Is it safe to say my T case is screwed? Is it possible the T case motor although it seems to function that it may be broken? I would think the selector lights would be blinking and not going into the different modes if that were the case? Think I bought a lemon