1984 GMC Brigadier? Any specific opinions?

i can't comment specifically on the detroit v-8 (i'm ASSuming it's a v type engine), because i don't know jack about diesel engines. However, i'm pretty confident that with this engine and the 9 spd,the tractor at least could comfortably tow 60,000lbs. The problem is that with only three axles for the whole combination, would this even be legally possible? 20 on the drive, 20 on the trlr and ASSuming you could get 20 on the steers (don't think so) you would need the extra wide tires.

i think the brigadier is a great truck in general. Especially if you can fix it yourself.

i don't care what anybody says GM knew how to make heavy duty trucks. So did ford.

 

Detroit made several HP ratings on that engine, starting around 270 on up to 335. The 335 is a 6V92TTA, while the other HP ratings are 6V92TT, with the A meaning the engine has an after cooler in the block. The tag on the valve cover will tell you if the engine is a TTA or just TT, and should have the HP ratings.

Start the engine cold and watch for excessive white smoke, especially puffing smoke, like from one cylinder, as this could indicate broken rings on a cylinder. It is normal to see white smoke for several seconds or longer, but white smoke after a minute or two is something to be concerned with.

The weak part of this engine is the block and crank. They are known to spin main bearings, and in doing so, spreading the main bearing saddle, cracking the block. Usually antifreeze in the oil or excessively worn bearings is the cause of this. If you have compression building in the radiator, then I would be concerned. It is also possible for the liner to crack below the ring line and leak water into the pan.

The best way to check for water or antifreeze is to crack open the oil drail plug when the engine has sat at least overnite, and watch to see if any water comes out before the oil does.

If you buy this truck, it wouldn't be a bad idea to drop the pan and pop in a new set of rod and main bearings. This is very easy and cheap to do with the engine in the truck. You can inspect the lower portion of the liners at this time. You will then have peace of mind as to the condition of the engine. I owned a 335 TTA in a single axle cabover IH. It was a very smooth running, powerful engine, that got very good fuel mileage for its time.

A 6V92TTA at 335 HP is very capable of pulling 60k and get decent fuel mileage if the overhead is set up correctly. You will need a two axle trailer to legally pull this kind of weight. The main thing is to check it out good.

 

Figure on 4 MPG and a gallon of oil a day. The story about oil coming from dinosaur bones is a myth. It comes from parking lots where cavemen parked their Detroits. I've seen thes engines pull 105,000 in the mountains of B.C., not fast but they did it.

I would say maybe $1,500. There are a lot of 90s trucks around for $5,000.

 

I drov a 1983 GMC astro cab over for a long time back in the nineties, it had the 6v92 with a 10 speed It had a grain box and i pulled a pup and sometimes a combine.. I went from montana to arizona to kansas back to montana.. it was slow on the hills but ok on the flat, got very good fuel mileage 12 miles to the gallon running empty if you believe that... it was fun to drive i enjoyed it fine... not a power house by any means but was fine by me...

 

Don't lug it under 1700 RPM. If you are holding 1700 up hill with the pedal on the floor, shift down a gear. 2100 RPM is the governed top, but 2200-2300 is no problem. The most power will be from 1900-2300.

The 335 is a powerful little engine.