Introduction
 

Hello all,

I am the new owner of a 72 GMC 478, 5 speed c7500. It has 20,000 original miles on it and an indicated 860 hours. It's original owner was the local fire department. a volunteer fireman decided it had a flat cam. My first pickup was a 3/4 ton 63 305 v6 4 speed that was 50 years ago and it was the best truck I ever had. So, I found it hard to swallow a flat cam. Bought it for $350 have put $1000 into it and this week it will get a Buick even fire HEI distributor.

Original problem was a failed alternator, battery would go dead not long after being unplugged from the station bay. Fuse on the battery maintainer was blown, someone had used a full 12 volt coil on it. Needless to say, by the time a call was over it would hardly run. the fire department knew the maintainer was not working so was using a commercial charger as a maintainer.

Have just about gone through the entire engine, cab, replaced the light bar, caution light bar in the rear, and siren. 25,000 pound load rating with power steering and power brakes (hyd. brakes so no CDL needed to drive it).

Need to identify which transmission is in the truck and which rear axle in in the truck, any help would be nice.

glenn

Re: Introduction
 

I have a brochure for a 72 7500 series truck that may mention what rearend and transmissions were s available. For starters the conventional cab in the 7500 series was either and H or J series there was no "C" designation. H for single rear axle and J for tandem rear axle.

Re: Introduction
 

Sounds like an interesting truck.

Post some pictures when you can.

Re: Introduction
 

Welcome and an awesome addition you have. Hope to see some pictures.

Re: Introduction
 

Hi,

Learn something every day. It is a H not a C.

Re: Introduction
 

Both the transmission and rear end are Spicer. Tanker overflow was dumping water on the differential and rear axle was full of water. Most of the oil was still thick and not pudding yet. 7.17 rear ratio was only good for about 60 mph and poor mileage. Carrier ordered for 4.56 ratio. Should be back on the road in two weeks.