Tractorman

13766-180HP. It must be the 180 horsepower alternator for the V6 Cummins 24 valve. - John

I have also wondered why I have not experienced some of the electrical problems that many others have. I bought my truck new and right away I put the grid heaters on a manual control switch. I very rarely use the heaters. And, like you, my alternator (a Bosch) has never given me trouble. I replaced brushes and bearings (only for maintenance, the alternator was working fine) three years ago at 216,000 miles. I am currently at 285,000 miles and the alternator passes your AC voltage test. I never tested for AC output until I came across your website and I will be keeping a close eye from now on. - John

That's the trouble with this site - lots of information tossed around about the beer, but no information of any value; like, where is the beer and who is bringing it? - John

I understand your dilemma here. If you replace a component and then recharge the system with refrigerant and it slowly leaks out, you will have three choices: go to an AC shop to recover the remaining refrigerant (the best solution, but costs money), wait for the remaining refrigerant to leak out (could be a long time), or intentionally dump the remaining refrigerant into the atmosphere (an environmental no-no). This same issue is what got me to start looking for a used R134A refrigerant recovery machine. I found a used Snap-on ECO 134 A for $650. It came with a new 30 lb tank full of R134A and a 20 lb recovery tank, lots of AC parts, seals, gaskets, tools, etc. This particular machine recovers, filters, and recharges refrigerant. It has a very accurate digital scale that measures refrigerant in ounces for recovery and recharging purposes. It is capable of collecting and releasing non-condensable gases and has an oil separator. It also comes with a vacuum pump for removing non-condensable gases, moisture, and for performing the leak test. When I was looking for a recovery machine I actually ran across two of this specific model Snap-on machine - the second one went for $250 (it had no extras). So, there are good used recovery machines out there and they cost a lot less than I expected. For me the refrigerant recovery machine has given me peace of mind because I now do not have to worry about the high cost of repairs and I can keep all of my vehicles charged with the proper amount of refrigerant at the beginning of each summer season. - John

How many miles on the AC components, especially the compressor? Last spring I had some of the same concerns that you had. I knew I had a refrigerant leak, but I didn't have any means to find it. I ended up buying a used Snapon 134A recovery machine at a reasonable price. Since my truck had the original Denso AC compressor still on it with over 260,000 miles, I decided to change it out with a new Denso unit. I then pulled a vacuum on the system; it passed the test so I recharged the system with 30 oz of refrigerant. I drove the truck for 600 miles and then recovered the refrigerant. I pulled out 30 oz, so I knew I had found the leak. Later, this fall I replaced the heater core. Again, I recovered 30 oz of refrigerant confirming that I had found the leak. When I replaced the heater core, I did not replace the evaporator core because it looked to be in very good condition. Time will tell whether or not I made a good decision. So, if you have high mileage on an original compressor, I would start there. The condenser would be the next likely place if it has never been protected by a screen. I believe that the o-ring connections on all of the line fittings are pretty reliable since there are two o-rings on each fitting. I have read that some people have had evaporator core failures. I would suspect these failures could be from some rubbing in the housing or from debris packing into the core since the evaporator core is the first place unfiltered air comes into contact with after passing through the blower fan. - John

Since you just installed the engine, I would check all air intake connections for the charge air circuit for boost leaks from the turbocharger outlet to the air intake plenum on the engine. - John

Excellent write-up! ... and complete with photos and wrench sizes. I know that I will have to address this at some point in time due to the age and miles on my truck. This is the kind of information owners of older trucks need to help keep repair costs down. Thank you. - John

It is true - there is no horizontal adjustment. My guess is that there has been some minor body damage on the left front side or right front side of your vehicle and that damage has misaligned one of your headlights. With your low beams on at night, can you tell which headlight is aimed correctly and which one is out of whack? It is likely that only one headlight is the problem. When you make this check, do it when it is not foggy. Thick fog can distort what you see. First make sure that you have the correct bulbs and that they are installed properly. Then inspect the area around each headlight to see if any of the headlight fixture's fasteners are loose, out of place, bent, broken, or missing. Worst case scenario is that you may have to take some things apart and reshape some body parts to correct the alignment. - John

I did do something similar back in 1988. I wanted a pickup or a van with a diesel engine and I became very frustrated at the choices available at the time. Choices like a heavy V8 engine, no turbocharger (really!), three speed transmission, all accompanied with lots of noise, smoke, high rpms and … no power! Just what I wanted. So, in the spring of 1988 I purchased a new Cummins 4BTA engine kit and put the engine in my 1984 Ford E150 van with a factory 4 spd manual overdrive transmission. I drove with this configuration for 87,000 miles (by then I had 212,000 on the vehicle). I lived in Leadville, Colorado (elevation 10,000 ft) at the time. With the Cummins engine, I could drive up a 7% grade at 65 mph in overdrive, and still accelerate! And no smoke! I was a happy camper. The van had two factory fuel tanks, one 18 gallons, the other 22 gallons. On one occasion after driving back and forth from home to work for a week (50 mile round trip) and then going on vacation traveling on top of the Grand Mesa pulling a small trailer with two ATV’s, I drove just over 1,000 miles without refueling. I netted just over 29 mpg on that fill-up. In 1991 I bought a new Ford F150 Extended Cab 4X4 and immediately swapped in the Cummins engine. Everybody thought I was nuts. I drove that truck for over 200,000 miles and then sold it. I kept fuel logs for over 100,000 miles of driving. The overall fuel mileage for the first 100,000 miles ( which including all driving and idling) averaged out to 22.5 mpg. It was a great engine! My next vehicle was a new 1999 Dodge with a Cummins. Somebody finally did it right! - John

My 6 spd manual transmission locks up in every gear, even reverse! However, it is very annoying the way you have to unlock it - you can't just flip a switch. If you don't unlock it during shifts, it makes grinding noises. - John

Here is a different way to look at it. Let's say the truck is going down a grade at 1700 rpm's with the torque converter locked up, no throttle input from the operator, and the truck's speed is being held constant with just the friction of the engine being forced to run at that rpm (the drag). If the torque converter is switched to unlock, the engine rpm's will fall immediately, not increase. The falling engine rpm will reduce engine braking. The truck will begin to accelerate. I have no experience with Toyota transmission controls, but I am guessing that there is more going on than just unlocking the torque converter. - John

IBMobile and I are saying the same thing. I hope we are not being included in the "you guys have it wrong" part. - John

I know that the automatic transmission does not shift into neutral when coasting, but it gives a similar sensation when the converter unlocks. Is it possible that you are feeling a programmed downshift when the brake is tapped in the circumstance you described? I believe that transmissions that have the "Tow / Haul" feature will automatically downshift on a downgrade when the brake is tapped if the "Tow / Haul" feature is turned on. In this case the converter will unlock during shift but locks up again after the shift and it is the lower gear that you feel holding you back. - John

Try this scenario. Pretend you are climbing a grade with a load using 5th gear in a 6 spd manual transmission. You crest the top of the hill and begin descending the other side. You like the feel of the engine holding you back a little.. You approach a curve and need just a touch of brakes to help maintain your speed. Would you shift the transmission into neutral at this time? I don't thinks so. If you were driving the same scenario with an automatic transmission in 3rd gear (OD locked out) with the torque converter locked up, then you would not want it to unlock the converter when you stepped on the brake. It would be kind of like putting the transmission in neutral. - John

I just realized that I gave you wrong information. I had it in my head that we were talking about a second generation truck. You are correct - on your truck the fan is controlled by the ECU, either when the engine temperature is high enough, or when the AC head pressure reaches around 250 psi. With that said, a different but similar situation could be occurring. If you have your ventilation setting in the defrost mode, the AC compressor will be cycling by default. With very little air flow through the AC condenser, the ECU could be telling the fan to come on because refrigerant pressure has increased significantly. It could be a combination of both engine temperature and AC head pressure. I apologize for the confusion on my part. - John

Possibly what is going on is that you have disrupted the engineered smooth, laminar air flow through the AC condenser core, CAC core, and radiator core . If very little air can enter the fan intake area, then very little air can leave the fan exit area so the temperature in that immediate area may rise fairly quickly and the thermo-sensor in the center of the fan hub will engage the fan. Once the fan is fully engaged, it will generate a considerable amount of turbulence and air recirculation because its air intake supply has been essentially cut off. The engine would not have to be "hot" for this to occur and the fan may run for some time. Without a winter front installed the thermal sensor in the center of the fan hub always has a smooth stream of air flowing across it - so it is very stable and engages the fan with repeated accuracy when necessary. What you could try is to have at least four separate openings in your winter front. They should be equal in size and be evenly spaced around the perimeter of the winter front area. The idea is to have several places for air to pass through without creating turbulence and to also have enough air flow to keep up with the fan speed when it is disengaged (the fan is always moving some air) If you get it right, then the thermo sensor will always have a stream of air passing around it. Some of the better winter fronts on the big rigs are set up like this. - John

I looked out my window this morning. There was a guy standing in the street with a breaker bar. I pulled the shade down. - John

Yes, you did mention it first - I missed that on my first read, so I apologize for that and thank you for letting me know. I had a '99 with an automatic (with temp gauge) and an exhaust brake for 70,000 miles. I controlled the exhaust brake and the lockup converter with a momentary floor switch and a throttle switch. This way I could lock the converter with or without the exhaust brake. Like you said, the transmission always runs cool. I have had the '02 with the six-speed manual for the last 16 years and 283,000 miles. For me it is a better solution. - John

You have now read several posts for different scenarios for having the torque converter locked up, and they are good posts. But, the really important reason hasn't been mentioned... and that is heat from normal torque converter slippage. Serious heat if you are towing up a hill for any distance and the torque converter is not locked. Heat takes out transmissions. The moment the torque converter locks up (with a lockup switch that you control), the automatic transmission instantly behaves like an manual transmission and the only heat that is generated is from moving parts, and that heat is minimal by comparison. - John

I know I am posting this a little bit late, but I wanted to clarify some things. I also apologize for any confusion on my part as to whether you should use the hand-operated vacuum pump or use the engine-driven vacuum pump for troubleshooting vacuum leaks. I use the hand-operated vacuum pump for troubleshooting vacuum leaks for two reasons. First, it comes with a vacuum gauge and a release valve which allows you to verify that the circuit being tested is holding a vacuum when you stop pumping. The second reason is that the hand-operated vacuum pump pumps a very small volume of air so that even a small vacuum leak is easily detected. The engine-driven vacuum pump is so powerful that even moderate vacuum leaks will go undetected because of the large volume of air it is capable of pumping. This is why it is not a good tool for finding smaller leaks. Also, If you do have small to moderate leaks, the air from the leaks will be continuously pumped into the engine crankcase by the engine-driven vacuum pump. This air will combine with normal engine blow-by gases and then exit through the crankcase breather.. The higher flow of gases (air mixed with engine blow-by) exiting the crankcase breather will make it appear that your engine has excessive blow-by. The additional volume from the combined flow may not allow the screen in the crankcase breather to catch all the oil droplets, so you may see an oily mist, as well.. In the last 283,000 accumulated miles on my truck, there were two occasions that under certain conditions I noticed an excessive amount of vapor in the air when the engine was idling. In each of these occasions (using the hand-operated vacuum pump) I found there were moderate vacuum leaks due to failing hoses or connections. Also, in each of the occasions all of the vacuum operated components (HVAC, CAD, etc.) performed as they should. So, just because all the vacuum components are working as they should doesn't mean that you don't have vacuum leaks. It is for the above reasons that I recommend using a hand-operated vacuum pump for troubleshooting vacuum leaks. Thank you, - John

A hand operated vacuum test pump is a good investment, is not that expensive, and will allow you to accurately diagnose vacuum related problems. For example, the CAD unit can easily be tested. Place the transmission into a gear and select 4-high or 4-low with the transfer case. Jack up the right front wheel and disconnect the vacuum lines at the CAD unit on the axle. Connect the vacuum pump to one port of the CAD unit; leave the other port vented to atmosphere. Operate the vacuum pump and hand rotate the right wheel to ensure engagement or release of the CAD. Swap connections and test again. Assuming that vacuum held on each test, one test should allow the wheel to rotate freely, the other test should lock the wheel in place which means that the CAD is mechanically doing its job. Using the vacuum pump you can continue with testing of all vacuum lines until you find the source of the problem. If both tests pass and the 4WD light does not come on, then you have a bulb failure, an electrical wiring problem, or a CAD switch contact failure. If the right wheel spins freely during both tests, then you have a CAD failure. Vacuum leaks on these trucks are commonly overlooked until something fails. The vacuum pump is very powerful and vacuum leaks can go undetected until they become large. Remember, all air from these leaks pass through the vacuum pump, into the engine crankcase, and then out the breather vent. You do not need this additional air flow out the breather vent! This issue alone is reason to invest in a hand operated vacuum test pump. - John

I just replaced my heater core about two weeks ago. I had the HVAC unit on the bench (the only way to do it in my opinion) and spent some time replacing weather stripping around doors and duct connections. I bought some universal adhesive weather stripping in various sizes for windows at a local hardware store. In some places where I needed a thin seal, I used the fuzzy side of adhesive Velcro. Whatever you use, just make sure it has a strong adhesive. I had already done the Heater Treater blend door repair and all vacuum lines and motors were in good condition and passed the vacuum test. I will be getting the after market cabin filter from Geno's - I definitely recommend it. My evaporator core had lots of debris blocking air flow. My windshield and side windows now stay clear and the heater keeps the cab warm on the lowest settings. Success! - John

I wired the intake manifold heater in my truck in the same manner right after I bought it in late 2001. I mounted a momentary switch on the steering column so it is very accessible and cannot be accidently left on. I don't mind the two codes that are set since I know what they are. My truck has been wired this way for over 280,000 miles and has never required any repairs. Mopar1973man makes a good point for those who live in areas that require vehicle inspections or emissions testing. - John

I would very much like to see some on-highway photos (low beam and high beam) of the light pattern from your truck's headlights. Hope you take the time to do that on one of your trips. - John

Dieselfuture is right on here. The factory evaporator drain on the firewall side does not have a downturn. So, when the seal between the AC housing and the firewall fails over time the condensation dripping from the drain follows the pipe right back into the passenger compartment. It took me awhile to figure this out because I thought it was from the windshield as well. I found a piece of preformed 90 degree heater hose the right size and pushed it onto the drain pipe. Problem solved - that was over two years ago. - John