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Common Problems Of The 454SS Pick-Up Trucks '90 - '93


 

I guess I need to take a moment to refresh everyone's memory. About one year ago I began administering the 454SS web site pages dealing with Tech Tips, Question and Answer area, and the For Sale section.

This has given me some valuable insight into the common areas that should be of concern to potential purchasers or new owners of these trucks. Why do I say new owners? Obviously, if you have owned your 454 for any length of time at all, you are discovering these problems first hand! You still might find some information of use here, as you might have been lucky with your own truck.

I must say that the 454SS has been very durable, utilizing the ¾ ton chassis under the sheet metal. Most of the common complaints on this vehicle are either because they are generally used to their full capabilities. Towing, drag strip action, and the occasional street race all fall easily into the capabilities of this truck. The down side is that these vehicles are now getting well on up in age, with the 90 model soon to be 10 years old. This is really sort of the normal life expectancy of any vehicle, and often the original vehicle manufacturer will no longer support the truck with replacement parts, etc.

Usually, the first parts to become obsolete are the cosmetic and trim items. So, when you purchase a 454, look carefully at the condition of interior items. Some of these are soon going to become hard to purchase. Thankfully, there are no common areas of trouble when it comes to the interior furnishings, but I wish someone could tell me why the driver's seat is offset and not square behind the steering wheel!

One common problem is the oil gage. (GM spelling) The sender goes out, and the gage still appears to work. The needle sometimes registers the normal pressures. But, just to test your reflexes, it will fall all the way down for a few minutes, or read nearly full scale. This seems to never be a solid failure, but is intermittent and somewhat hard to diagnose. Just replace the sender and you will be back in business

Looking around the interior, the other problem area is the sliding rear window. I think every 454 I have been in has either a rattling window, or one that leaks, or both! The best fix here might be to simply replace this factory unit with an aftermarket piece, or find a factory fixed window with the rear defogger grid made into it as an upgrade. I almost never use the rear slider, because road draft draws every piece of grit and dirt on the road into the cab of the truck. Just run your hand over the console top after driving some distance with your rear window open, and you will see what I mean! The other approach is to have someone help you pop out the rear window and re-seal it using a new rubber gasket available at any auto glass installer. The window just pops out, with someone pressing from the inside, and someone outside to catch it.

Small strips of cardboard sheet slipped in between the tracks for the glass and the frame will usually fix the rattles.

Windshield. Most have been changed out by now, but a bunch of the original Guardian brand I have seen have started to delaminate. All at the edges near the bottom sides. Just a quality control problem, but it can be unsightly and eventually require changing the glass if the delamination gets bad enough. Anyone reading this that works at Guardian is welcome to send me a new one!

Here is a controversial subject: Paint. The factory was for a long period doing the duct tape test. This test is where they stick a long strip of good quality duct tape to the truck and press it down firmly. Then, they yank it off and see how much of the paint comes off with it. I do NOT recommend you try this at home. The factory paint will come off in a sheet. You will feel stupid, and the 454SS web site disclaimer keeps us out of trouble. You did read the disclaimer, didn't you? GM repainted a bunch of these trucks under warranty. This was actually a primer problem, more so than a paint problem. The two just didn't stick together. Usually the leading edge of the hood is the first place to go bad. Look carefully for a repaint. Almost all of these trucks have by now been repainted due to the factory paint defect, or due to collision damage.

So let's get busy and look under the hood. We do have some problem areas here. First and foremost is the braking system. Briefly, brake fluid is hygroscopic. It absorbs moisture. I just know everyone changes their brake fluid every year. You don't? Does the fluid look like used engine oil? It might be too late. Really, you should change the fluid every year, using a premium product such as Castrol LMA (Low Moisture Absorptive) brake fluid. ATE, a German company, also makes a premium Super Blue Racing fluid, that is much better than standard types. Got an old can of fluid that you didn't use up? Throw it out. The fluid is usually shot if it has been in an opened can for long. All this talk is leading up to the problem area.

Brake master cylinder and deboost valve. These things are expensive and usually both go out as a pair. Got a mushy pedal? (I mean more than normal..) Here is your problem. Change both pieces. Ouch. Wanna really help the brake feel after this repair? Change the rubber hydraulic lines to stainless steel ones when you do this job. The steel lines don't swell and expand under heavy use like the rubber ones do, and you are rewarded by a much improved brake system feel and response.

Ball joints. No sophomoric jokes, now. (90 models) Here is one Chevrolet really put on us owners. The castor and camber adjustments are fixed on the truck from the factory. Meaning the only adjustment you can make is toe-in. This is fine unless you drive your truck on the street, with potholes and Ford Festivas to run over. Or, if you lower your truck, you will need to set these adjustments. What does this have to do with ball joints? Plenty. The ball joints were sealed. No grease fittings. These things wear out faster than the idler arm on a 85 Z-28. Chevrolet realized this, and issued a service bulletin that specified changing the ball joints out, and also to remove the fixed alignment brackets and fit adjustable cam bolts. If you look at your ball joints, and they have grease fittings, the bulletin was done. If the shop knew what it was doing, they should have also fitted the adjustable cams for the alignment at the same time. This was not a recall, and not many of the trucks were fixed or updated. You will have to look and see if yours was done.

Accessory brackets. They break. A lot. Check behind the A/C compressor for a round tubular brace there. This is a later production change that will help this problem. Missing? You might still be able to get this at the dealership. The compressor vibrates and will eventually break the bracket. There are also several belt sizes that can be installed on the truck. Check the length of your replacement belt and be sure it matches the original. The idler pulleys break a bunch too. There has been about 2 or 3 part number changes here. Get the latest one from the dealer, and you should be OK. It is metal, and looks like it is made from 2 sections. If yours is plastic, it will break. Here is one engine that will see benefits from a set of underdrive pulleys.

Everything that rotates under the hood. Alternator, water pump, crankshaft, etc. all have a reduced life span on this truck, because of the 3.73 gearset, and no overdrive transmission. (90 model) These big blocks are turning hard just to keep up with traffic. About 3000 RPM for 70 MPH. My rule of thumb is to not turn an engine beyond ½ of its red line for extended cruising. This makes you a road hazard in the 90 model. Granny will give you the finger as she blasts past in her Pinto. The aggressive Grannys will turn on their dome light at night so that you can see them giving you the finger!

91 model four speed automatic transmission. This was a great factory upgrade that went a bit wrong. The big four speed is really fragile. The torque converter clutch won't hold and often burns up. Got a judder in the drive line at large throttle openings, noticeable just before kick-down? It might be this problem. Light brake pedal pressure with the left foot (just enough to turn on the brake lights) while keeping the throttle open with the right will disengage the TCC. Does this cure your judder?

Of course, all that TCC lining being burned off the friction surface has to go somewhere. How about into the filter screens of the control solenoids? Yep, here is another problem area. First indication of an internal problem is usually the transmission being slow to go into 3rd, or a slight slip and flare of revs as the gearbox changes out from 2nd to 3rd. What does the fluid look like? Red to dark red is normal. Brown is usually too late. Does it smell burned? Way too late! Sometimes the transmission will not even work with fresh fluid in it, because the old dirty fluid was so viscous. It is not uncommon to do a fluid and filter change and find that the truck will not engage any gear afterwards. Put the old fluid back in and it will usually work for just a while.

The 92-93 models are better, as there were several fixes to this transmission for 92.

90 model. The Turbohydramatic 400 is pretty tough, having been used in many models previously. Look to see if it has the recall dipstick. Red handle that locks it into the tube? You have the recall part. The transmission under heavy load will spit the original dipstick out along with a goodly volume of fluid that lands exactly on the right exhaust manifold. Time for the hot dogs and roasted marshmallows, cause you have a nice fire going.

Differential. It does weird things, but usually doesn't break too much. If your posi action is erratic, letting you feel foolish when you leave one looong black streak on the pavement, all you need to do is change the fluid. No additive. None. The fly weight unit can be a bit picky as to which grade of gear lube you use. Stick with the factory recommendation here.

90 model pancake style catalytic converter. This part is junk. It is the SAME part number as the one under the 350 cubic inch truck. Do anything you have to within the scope of your local laws to get rid of this thing. They also stop up, costing you horsepower and fuel. Lose it and as a minimum, replace it with one of the monolithic style aftermarket replacement units. (Monolithic - you can see through it - honeycomb core)

91-93 exhaust is fine. The mufflers tend to rot out because they do not drain condensation because they are on their side under the truck.

U-joints. The rear ones go out most often. Usually this is on a truck that has been lowered. If the operating angle is different for the two u-joints, the driveline will resonate or vibrate at certain speeds. Sometimes under load, sometimes on decelleration. If your truck is lowered and you are using up u-joints, think about adding some 2 degree shims added to the spring bundle to drop the front of the differential down and regain the correct u-joint relationship.

Oil lines from the oil filter adapter to the radiator cooler. These lines use a press lock type connection. They almost all leak a bit. Some do need repair, and GM has a kit to reseal the line ends.

Electrical problems. Yes. Almost all of the problems are on the engine harness around the exhaust manifolds. It gets really hot in this area, and toasts the little plastic brackets that keep the wires from touching the manifolds. Once these brackets are melted or get so brittle they break and get gone, the wires will melt onto the manifolds and cause many strange problems. Headers will only be worse, because the primary tubes are so close to the area where the wires run down. Look here first for strange electrical gremlins that seem to be erratic and effect the truck in different ways.

Radiator. This is a composite radiator, using an aluminum core and crimped on plastic tanks. These are starting to go out, again, primarily because the anti-freeze hasn't been changed every year. Sound familiar? The anti-freeze has a corrosion inhibitor package added to it during manufacture. This inhibitor wears out over time. If it is not changed, the anti-freeze basically becomes an electrolyte, and you have made a battery out of your engine and other dissimilar metals contacted by the coolant. The first result is usually the seals that are crimped on under the end tanks start leaking. No solder repair like the old days. You end up replacing the radiator now. The good side is that there are 3 core radiators available for the 454SS. So you get a good cooling upgrade if you go for the additional expense of the 3 core piece.

Fuel filter. Change it. Every year. This will cost you more power than you would believe. The filter is small and will not hold much contaminant. No one ever seems to change this thing. It is on the frame rail under the truck. I always pour out the old one in the reverse direction while shaking it, (shaking the filter, of course!) and watch the gas flowing out to see how much contamination was in the filter. You will be surprised. Just remember to take off the gas cap to keep tank pressure from forcing gas out on you while you change the filter. It doesn't hurt to unplug the fuel pump relay and run the engine at idle until it cuts off to relieve the fuel pressure in the system. Remember, the pump is in the gas tank, so the fuel lines are all pressurized, and will hold this pressure for quite some time. Be careful.

Oxygen sensor. Got more than 60,000 miles on your truck? Change this part now. The O2 sensor is a small voltage generator, and eventually just wears out. It is exposed to the heat of the exhaust stream and it just eventually wears out. Some fuel contamination can kill it instantly. Also, many of the aromatic RTV silicone sealants will also instantly kill an O2 sensor. Do a new intake with RTV silicone? It's almost a sure bet that the O2 sensor is damaged.

High idle speed. A bunch of these trucks turn almost 1000 RPM at curb idle. No one seems to be able to explain why only some of these trucks do this. Not so much a problem as a nuisance.

You have noticed, I am sure, that I did not even give mention to the normal wear items like tires (OK, rear tires specifically!) and hoses, belts, brake linings, and so on. You will expect these to wear out and have to be replaced on a mileage basis.

Use good quality replacement parts. Do not scrimp here. In almost all areas, AC/Delco has established parts dealers that are not located in a dealership. Here, you can purchase factory AC/Delco replacement parts at much reduced prices. Way less than the dealerships. Look for these parts stores that advertise that they are an AC/Delco stocking dealer.

I will not get into which oil is best or which filter. There are as many opinions here as there are mechanics working on cars. What do I use? Well, since you asked...

I use exclusively Castrol 20w-50 in the truck. Also, always the AC/Delco oil filter. The long one. This is the PF-35. I always pre-fill the filter so the engine doesn't have to run without oil pressure for an extended time while the new filter fills up. The PF-35 holds almost one quart, and takes a while to refill while the engine bearings and cam faces are running on a residual oil coating. Note: The highest oil load occurs at the lifter/cam working surfaces. Who would have figured?

 

Thanks for sitting through all this. Send some E-mail my way with any comments or corrections. It is not uncommon for me to add readers comments to the end of an article after it is published.

Be constructive. I do not add the comments about my genealogy! Seeya!

Tweek

So here I am back again with some updated information:


These trucks all use an all metal radiator, with 4 cores. The tanks will accomodate a 5 core center, and can easily be re-cored for an update. I have no idea where I got the plastic information from. Duh.

Do your black plastic center caps on your factory wheels look distorted and melted? Believe it or not the sun's reflection is focused exactly on the center caps of these wheels. You guessed it, the caps melt and get distorted. The factory fix is to use the chrome ones to replace the black ones. Also, there has been mention of the factory wheels found bent from time to time, causing ride problems.

The factory fixes for the four speed automatic (4L80E) occured in 1993, not 92 as stated.

Exhaust manifolds crack on the 454 duallys a lot. I am not sure if this is isolated to just the trucks that are doing a bunch of towing, or if it applies to any 454.

You can still get the body side graphics from GM. This might soon change. They are cheap. Get the hint?

Lots of these trucks are starting to get some real miles accumulated on them. How about taking a look at the suspension and body rubber bushings. These things wear out like anything else, and should be looked at as milage and age set in. Also, a look at the pitman arm might be a good idea, as it has been mentioned as a possible wear item.

Thanks for the response to this article, and I might have to update it again in the near future. Seeya,   Tweek

 


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