Living the good life Happy Jack Arizona. Vet Sea Bees, vietnam vet, love all types of equipment. Just bought a 1975 Chevrolet C65 with a snowplow and dump bed, automatic transmission a a 366 engine, single axle, 55,000 actual mileage, needs a ton of work but it drives and the plow and dump do work.
Welcome. Am I the only one wondering why you have a plow in Arizona? 366, Tonawanda? I remember those, lots of broken manifolds. Is yours gas or natural gas? We had a fleet of natural gas ones out here.
We are at 7000 feet and we get about 3 feet of snow each year. Mine is a gas engine, just got it here yesterday and haven't had a chance to really inspect it yet. The guy I bought it from said it has a rebuilt transmission. Not sure what type it is, it's huge. It also shifts extremely hard. Any idea what that might be?
Probably a 545 Allison. They weren't computer controlled, just a throttle valve. All that body with a gasser, I'm sure your shifting @WFO. So the line pressure is jacked from the throttle valve and you get a hard shift, or, or ... The guy who rebuilt and installed it didn't adjust it properly. That's a common. If you roll on a flat grade at partial throttle, does it still kick you in the pants? If so, probably needs an adjustment. Section 5-9 happy reading
Welcome to HEF Dennis !
Yes when I roll on the flat it shift down extremely hard. What kind of adjustment are you talking about?
Please see the attachment on previous post.
Sorry, new here and missed the attachment.
Lots of reading but very good Very solid information
Welcome to HEF, Dennis !!
Welcome to the Forums Dennis! Honor to have you.
Ok I finally had some time to look at this again. Thanks to funwithfuel for the tech info. My trans is a AT545RM with no cable from the carb or a computer. Looks like mine only has a vacuum module to make it shift. The module I have appears to be non adjustable. Can I change the module to make it shift more smoothly?
Before you make any adjustments, have you checked your vacuum signal at the modulator?
I have 12" cold at idle.
You want to see 16-20" , you have a bad vacuum leak. I'll bet your eyes burn while she's running. Quick check, take a little WD40. Spray around intake manifold and all vacuum connections. Any change in rpm indicates a vacuum leak. Do you have air brakes or hydraulic? Hydraulic, check the vacuum booster. In fact cap off all vacuum signals and see what your manifold vacuum is. If you still have 12, spray some starting fluid in the oil filler. This will tell you if you have a bad intake manifold gasket internally. Just a whiff, no need to drown it. What ignition system is on there? Points, HEI aftermarket? Post a pic if you can.