Wrenchin... Adventures under the hood... Put em here.

[El Chupacabra]

More fun times with the old Sierra: trying to track down a vibration that occurs at 45-60 mph; nothing lower than 45 mph, pretty much gone by 65 mph.

Tires are new, stock size highway tread on stock wheels, road force balanced -- back to the tire shop a couple times, as that was my first guess at the vibration cause. Vibration was there with the old tires too, which were an AT tread.

Truck is stock height, not lifted or lowered. No leveling kit, no torsion bar cranking.

The rest of the new or nearly-new (within 8000 miles) parts that have anything to do with suspension or drivetrain: all shocks, steering stabilizer, complete front end rebuild (complete upper control arms w/ ball joints, replaced lower ball joints, complete inner + outer tie rods, pitman arm, idler arm + bracket), alignment, all U-joints in front and rear driveshafts, both front hub assemblies. Play (lash) in the front and rear differentials seems reasonable, ditto for the transfer case.

About the only rotating part left is the front CV axles, which felt a little rough when I did the front end rebuild, but they didn't seem all that bad in my hands. If I pull on the CV axle center section by hand, I can get the driver's side to move a bit up/down (relative to the ground). Boots aren't cracked, no leaking grease. No clicking sounds when driving + turning. I suspect they may be original -- 200K miles and 20 years ago.

Any guesses at diagnosis other than the CV axles?

Well, I'm still working on chasing down this vibration problem. Since this post, I've replaced both front CV axles - - both the old ones were original and a little clunky by now (2005 truck, 207K miles). This eliminated some random clunking sounds I was getting, but didn't make a difference on vibration.

Back to tire shop: Discount Tire replaced another tire under warranty, it was out of round and wouldn't road force balance. Vibration improved some, but still there. FWIW they're street tread tires - - 265/70/17 Kumho HT51, basically a copy of the Michelin LTX MS. Mounted on stock wheels. Discount Tire did not think the wheels were bent.

Pulled rear driveshaft again, and the rear U joint I'd replaced earlier this year was a little notchy -- maybe I buggered up the replacement, maybe it's defective. Replaced and did it very very carefully -- it's butter smooth by hand. Reinstalled, greased, and still vibration. I've measured driveshaft angles, and they're pretty good -- truck is stock height, no lift.

Currently: vibration noticeable at 45 mph and higher, seems to smooth out around 65-70 mph (or it just vibrates so fast that it seems like it's smoother). No difference if accelerating, braking, or turning. No weird noises like squeaking or growling. Brakes in straight line, no pulling when braking.

On a straight road, shifting into 4WD around 40 mph and accelerating up to 55 or so, it felt smoother -- as if engaging the front end helped damp the vibrations. It's a part time 4WD system so I can't really run it too long in 4WD on dry roads.

What I'm looking at right now: possibly transmission mount has deteriorated to where it's affecting driveshaft angles? Current mount looks original, some rubber cracking, I can wiggle the transfer case a bit -- doesn't seem that bad, but a new one is like $10 so I ordered one.

Anyone have any other ideas?

[tuco]

Maybe the driveshaft is slightly out of balance

[El Chupacabra]

Maybe the driveshaft is slightly out of balance

I think that's my next thing to have checked properly. No visible dents or missing weights,, but it's totally possible that it's out of balance.

[bearcub69]

who here has a 7.3l powerstroke? im considering buying an f250/f350
although the obs are sexy.. would probably like a 1999-2003 model.
i hear how reliable they are, but ive joined a few groups and done some research and it seems like many people are constantly fixing/replacing things.. which doesnt really surprise me since most people buy used and you never truly know what the previous owner did.. and the trucks are 20+ year old fords now...

i just want a good used 3/4 or full ton truck that is reliable

[warthog]

Plasti dip works, sort of. It goes on easily enough but it's time consuming to keep layering thin layers so it eventually covers everything thick enough to be smooth looking. As far as being peelable, well, again sort of. Like with any paint it doesn't come off the areas it adhered to very well. The episode created could go in the shit that annoys you thread. Just commit to a color and paint it.

Hold that thought.
I have pictures. I agree, but with a lot of caveats. Mainly, you are not supposed to leave dip on for more than a few years before redoing it. If you close to just recoat, that is fine, but know that you will need solvents and possibly a pressure washer to take it back off.

[warthog]

OK, here is my Hyper Dip project I did recently.
I used the Piano Black
Website:
https://www.dipyourcar.com/collectio...SAAEgIKN_D_BwE

Company doesn't allow us options, so I customize my vehicles the best I can.

Wheels Before:




Wheels After-






Grill Before:




Grill Finished:


Love this stuff- the kit comes with everything you need. Just follow their instructions closely.
I am doing the badges next- that will be a lot of work and will need to apply a lot of releaser to get it to work.

[anotherVTskibum]

who here has a 7.3l powerstroke? im considering buying an f250/f350
although the obs are sexy.. would probably like a 1999-2003 model.
i hear how reliable they are, but ive joined a few groups and done some research and it seems like many people are constantly fixing/replacing things.. which doesnt really surprise me since most people buy used and you never truly know what the previous owner did.. and the trucks are 20+ year old fords now...

i just want a good used 3/4 or full ton truck that is reliable

I bought a 7.3-PS-powered box van when I moved from Vermont to Montana, and it was about 20 years old at the time but with relatively low mileage. Probably 70% of the issues were related to prior ownership habits and me taking it to full interstate speed for days on end, but I'm not so sure the failure of one of the high-pressure oil lines falls into that category. The fix wasn't hugely expensive, but getting the rig towed to a shop and actually getting it worked on was a PITA.

The transmission also shit the bed on me, but I have no idea if putting fresh fluid in before departure would have avoided that issue, and in hindsight, I wouldn't be shocked if it had OEM fluid. The Internet definitely seems to think the E40D isn't as strong as the 7.3PS.

Once I got to Montana, I did find that it needed to be plugged in to start below about 20 degrees, which of course was a lot of the time. It would retain enough heat in the block that a few hours later it would start fine, but overnight not so much. May well have been a glow plug issue, but using an extension cord was easier than doing those.

Given what I was seeing 7.3PS rigs going for when I last looked, I'd be way more inclined to buy a modern gas rig unless I had a use case that really needed the diesel. YMMV, of course.

[bearcub69]

I bought a 7.3-PS-powered box van when I moved from Vermont to Montana, and it was about 20 years old at the time but with relatively low mileage. Probably 70% of the issues were related to prior ownership habits and me taking it to full interstate speed for days on end, but I'm not so sure the failure of one of the high-pressure oil lines falls into that category. The fix wasn't hugely expensive, but getting the rig towed to a shop and actually getting it worked on was a PITA.

The transmission also shit the bed on me, but I have no idea if putting fresh fluid in before departure would have avoided that issue, and in hindsight, I wouldn't be shocked if it had OEM fluid. The Internet definitely seems to think the E40D isn't as strong as the 7.3PS.

Once I got to Montana, I did find that it needed to be plugged in to start below about 20 degrees, which of course was a lot of the time. It would retain enough heat in the block that a few hours later it would start fine, but overnight not so much. May well have been a glow plug issue, but using an extension cord was easier than doing those.

Given what I was seeing 7.3PS rigs going for when I last looked, I'd be way more inclined to buy a modern gas rig unless I had a use case that really needed the diesel. YMMV, of course.

yeah the e40d isnt great from what ive read, which is why im considering going for the 99-03 models with the 'more reliable' transmission. the one im looking at already comes with a block heater and has relatively low miles. i just know if these things havent been taken well care of they can be a pita for the next guy like me... and im not trying to buy a headache.

im open to a more modern gas rig. i dont need a diesel.. the 7.3l ps caught my eye due to its longevity and they can also get decent mpg. i just want a 3/4 ton or full ton and i think the more modern gassers that arent pieces of crap are probably pretty expensive..

[The Reverend Floater]

I've owned a few. If you know how to fix or replace:

Glow plugs and harness! (Pain in the ass)
Camshaft Position Sensor (keep one in the glove box)
Starter (easy)
Alternator (easy)
Fuel filter (easy)

Then you have yourself a pretty reliable truck. And yeah, use Howes or another diesel treatment and definitely plug it in whenever it's below ~20*f. Those old radiator covers work well on them for appropriate weather. They respond well to those tractor intakes and bigger exhaust/down pipes and really do well with a economy tuner. They're fun to wrench on because unlike most modern rigs, you can see improvement without sacrificing reliability.

They're not fast and not even that impressive torque wise compared to modern HD trucks but they are comfortable and capable.



Sent from my SM-S928U1 using Tapatalk

[bearcub69]

I've owned a few. If you know how to fix or replace:

Glow plugs and harness! (Pain in the ass)
Camshaft Position Sensor (keep one in the glove box)
Starter (easy)
Alternator (easy)
Fuel filter (easy)

Then you have yourself a pretty reliable truck. And yeah, use Howes or another diesel treatment and definitely plug it in whenever it's below ~20*f. Those old radiator covers work well on them for appropriate weather. They respond well to those tractor intakes and bigger exhaust/down pipes and really do well with a economy tuner. They're fun to wrench on because unlike most modern rigs, you can see improvement without sacrificing reliability.

They're not fast and not even that impressive torque wise compared to modern HD trucks but they are comfortable and capable.



Sent from my SM-S928U1 using Tapatalk

yes ive read to keep a camshaft position sensor and an idm? in the glovebox because they can leave you stranded. i figured a harness would be difficult, but didnt think glowplugs would be too bad, but ive only replaced spark plugs. you mean the wiring harness or the glow plug relay?

[Mazderati]

Buying an old vehicle for reliability is risky, IMO. Even reliable platforms age into problems. Fun vehicles are a different story.

[warthog]

E4OD isn't too bad, as long as you get a good one.
Total gamble, depending how it was treated.
Fluid can tell the tale, but PO could have just changed it.

That said, they do shift oddly, and several things like 3rd brake lights, PSOM, and rear sensor can imitate a failing tranny.

[gravitylover]

Buying an old vehicle for reliability is risky, IMO. Even reliable platforms age into problems. Fun vehicles are a different story.

^^This. Somewhere around 10 years is when things just start aging out. Wire coverings, plastic clips and plugs, brake and hydro lines, coolant overflow tanks and the obvious hoses and other rubber bits like ball joint boots, these all start to fail either from underuse or just because they want to.

[El Chupacabra]

^^This. Somewhere around 10 years is when things just start aging out. Wire coverings, plastic clips and plugs, brake and hydro lines, coolant overflow tanks and the obvious hoses and other rubber bits like ball joint boots, these all start to fail either from underuse or just because they want to.

At 10 years? Only if you live in very harsh climate - - salt belt at one extreme, or Phoenix / Vegas and you park outside, uncovered, at the other extreme. Or just high miles per year, like 25K+.

I'd agree that at 20 years parts are needing attention, if they are still original. But by that time, many wear items should have been replaced anyway.

Old trucks can be just fine, so long as you recognize you're going to have to put in work and have to learn how to repair yourself - - if you're going to bring it to a shop for everything, it's not worth it.

IMHO what kills a vehicle: rust, abuse, flooding, fire, or significant accident. Otherwise it's just parts that wear out.

[gravitylover]

At 10 years? Only if you live in very harsh climate - - salt belt at one extreme, or Phoenix / Vegas and you park outside, uncovered, at the other extreme. Or just high miles per year, like 25K+.

I'd agree that at 20 years parts are needing attention, if they are still original. But by that time, many wear items should have been replaced anyway.

Old trucks can be just fine, so long as you recognize you're going to have to put in work and have to learn how to repair yourself - - if you're going to bring it to a shop for everything, it's not worth it.

IMHO what kills a vehicle: rust, abuse, flooding, fire, or significant accident. Otherwise it's just parts that wear out.

Salt? Check
45-50" of precip in a regular a year? Check. I've had 85" between 7/1/23 and 6/30/24, no it's not a rainforest just a typical northeast suburb.
Park uncovered and exposed to all elements? Check
High miles? Check. 35k is a short year, even at the height of covid I still did 25k, this year I'm at 26k already.

Keeping it wrenchin' related - I changed both front axles on the POS this morning and it feels SO much better but while I was down there I found a new leak. It looks like I'll be replacing the steering rack sometime this week This month it looks like I'll spend as much on maintenance as if I had a car payment and new car insurance. On the upside, it is running pretty well and I keep getting in and doing 800+ mile road trips every week without breaking down

[gravitylover]

Anyone have experience with Aisin racks? I've liked their transmissions that I've had but don't think I've had an Aisin rack and pinion (and tie rods). This may be a bigger job than I want to tackle but I thought that with the axles and they were easy.

[El Chupacabra]

Well, I'm still working on chasing down this vibration problem. Since this post, I've replaced both front CV axles - - both the old ones were original and a little clunky by now (2005 truck, 207K miles). This eliminated some random clunking sounds I was getting, but didn't make a difference on vibration.

Back to tire shop: Discount Tire replaced another tire under warranty, it was out of round and wouldn't road force balance. Vibration improved some, but still there. FWIW they're street tread tires - - 265/70/17 Kumho HT51, basically a copy of the Michelin LTX MS. Mounted on stock wheels. Discount Tire did not think the wheels were bent.

Pulled rear driveshaft again, and the rear U joint I'd replaced earlier this year was a little notchy -- maybe I buggered up the replacement, maybe it's defective. Replaced and did it very very carefully -- it's butter smooth by hand. Reinstalled, greased, and still vibration. I've measured driveshaft angles, and they're pretty good -- truck is stock height, no lift.

Currently: vibration noticeable at 45 mph and higher, seems to smooth out around 65-70 mph (or it just vibrates so fast that it seems like it's smoother). No difference if accelerating, braking, or turning. No weird noises like squeaking or growling. Brakes in straight line, no pulling when braking.

On a straight road, shifting into 4WD around 40 mph and accelerating up to 55 or so, it felt smoother -- as if engaging the front end helped damp the vibrations. It's a part time 4WD system so I can't really run it too long in 4WD on dry roads.

What I'm looking at right now: possibly transmission mount has deteriorated to where it's affecting driveshaft angles? Current mount looks original, some rubber cracking, I can wiggle the transfer case a bit -- doesn't seem that bad, but a new one is like $10 so I ordered one.

Anyone have any other ideas?

Update of sorts:

Installed new transmission mount, vibration became sharper / crisper - - old mount was definitely original, and while not totally deteriorated, it was a lot softer and a little shorter than the replacement. I used an aftermarket one, because the GM OEM ones are $120.

Then tried a complete new rear driveshaft. Still vibrating, no difference, so I think I can rule out the driveshaft and the U joints. Going to return the new driveshaft and reinstall the original one. (Autozone is useful.)

I'm out of ideas. Made an appointment with a driveline shop about a week and a half out, they can fix anything it may be - differentials, transmission, transfer case... Something just isn't right.

[Rideski]

Hot weather got the best of me.
Popped a hose lost water.
Hope I didn't mess the water pump or worse yet the heads. Shut it off before the needle pegged but it was up there for a minute.

I think I can replace the "quick" fitting myself, but a tad dubious about the water pump. Maybe. Not looking forward to it.

Better tools and a garage would help a lot. Or at least a concrete slab to jack it up. Had a buddy with an over the top garage but that luxury has passed. Seems like Aldo or Bob should open a shop in Denver. Tons of biz around here.

[El Chupacabra]

^^^ I recognize that. GM truck of some sort, right?

The part left attached to the stub at the firewall is held on by a clip - - there's a special plastic tool to pop off the attachment. Then you can replace the whole hose easily.

I just ordered a whole set of replacement heater hoses, radiator hoses, and the coolant lines that run through the throttle body. Some of the ones in my truck look possibly original (2005 model), so I'm going to baseline by replacing all of them.

[warthog]

Hot weather got the best of me.
Popped a hose lost water.
Hope I didn't mess the water pump or worse yet the heads. Shut it off before the needle pegged but it was up there for a minute.

I think I can replace the "quick" fitting myself, but a tad dubious about the water pump. Maybe. Not looking forward to it.

Better tools and a garage would help a lot. Or at least a concrete slab to jack it up. Had a buddy with an over the top garage but that luxury has passed. Seems like Aldo or Bob should open a shop in Denver. Tons of biz around here.

Got a hilly driveway?

[Rideski]

It's a 2012 Tahoe. New to me a couple years ago, 130k miles.

Sounds like the hose is $100, wouldn't mind replacing the fitting and leaving the hose. Seems in good shape.

I do have a sharp rise at the end of my driveway (3/4" crusher granite) where I've been changing my oil for years along with various other things like swapping radiators etc. But I don't jack up cars on it, doesn't seem stable enough. Haven't even located the water pump yet, new to me vehicle. I changed the water pump on my Jeep XJ but there was lots more room to maneuver in that engine bay.


Edit oh, no wonder I can't see it, it's buried behind that snorkel. I need one of those pry tools, oh and that swivel socket, and that 90 degree power wrench, and... Fuck it. I hope it's just a hose leaking down there...

Hats off you you guys at home doing this level of stuff without pro tools and training.

[motopsycha]

After a ton of work a few weeks back doing oil pan gasket, motor and trans mounts on my 128, the drivetrain developed a vibration while under load. I found a rear u-joint that was notchy and stiff. I soaked it in some solvent to get it freed up (to confirm diagnosis not as a permanent fix) and it was resolved. I should have noticed this when I had it out the first time.

Ordered a new driveshaft and got it installed last weekend only to find it to have a nasty vibration starting around 60 mph. The guys I ordered from sent it out a replacement no problem but this was the 5th time I’ve had it out in the past month.

Good news is everything seems to be good with replacement #2

[El Chupacabra]

It's a 2012 Tahoe. New to me a couple years ago, 130k miles.

Sounds like the hose is $100, wouldn't mind replacing the fitting and leaving the hose. Seems in good shape.

The hose may not be long enough once you remove the OEM flitting at the firewall (that fitting attaches to a stub end of the heater core). Remove carefully, you don't want to damage the heater core - - those are a PITA to replace.

I'd recommend replacing the other heater hose attachment too (the white one in your pic). It'll be brittle too, and likely to fail

[Rideski]

Yeah the other one looks yellowed as well. I'll study up a bit more before I start.

[El Chupacabra]

Yeah the other one looks yellowed as well. I'll study up a bit more before I start.

This is a good overview:
https://knowhow.napaonline.com/how-t...se-connectors/