: Towing with a Cadillac
04-12-11, 02:13 AM
I know the 91-96 Fleetwoods can tow up to around 6,000lbs. I saw an article in Popular Mechanics about it.
How much can the older ones up to 79 tow? It seems like they have a bit tougher transmission,turbo 400 , and the Big Blocks can put out a lot of torque.
With the addition of an auxilary cooler and electric fans the 400 would stay plenty cool
I guess the differential and suspension could be upgraded to maybe a commercial chasis one. How much weight can the regular, or commercial differntial handle? The shocks could be replaced with air bigs
How much weight could the stock set up pull. And with mods how much weight could a caddy haul?
I think the bolt on trailer hitches are pretty strong. And when not in use the ball could be replaced with a chrome propeller. That would look fitting on the land yaht.
Assuming the trailer has electric brakes, and electronic brake controller installed
Are there bigger brakes to be had on the car itself?
04-12-11, 09:03 AM
With the right rear gear ratio, adequate engine & trans. cooling and some heavy-duty rear suspension components any big block Cad. would make an excellent hauler. Forget airbags: get Monroe heavy-duty coilover shocks and some fresh HD rear springs, maybe from a 9C1 Caprice if you can locate them. A trans cooler would be a good idea.
Rear ratio for commercial chassis in 1980 for example was 3.08 so I would at lease start there. Maybe a 3.42 would be a good ratio for hauling?
04-12-11, 09:15 AM
I had a '77 coupe, set up for towing. It had the coil over rear shocks and the stock rear gearset.
The 71-96 Fleetwoods, setup properly, are "Not to Exceed 7000 lbs".
The brakes aren't big enough to do heavier safely in my opinion.
Also, you MUST have the 8.5, 8.875 or 9.5" axle, not the spindly 7.5 like some had.
As a guide, the HD towing gear on the 71-76 cars was 3.23, the 77-79, don't know, probably the same. The later 91-93 cars were 3.73 geared, and the LT1 cars were 3.42.
I would NOT risk towing with tall gear like 3.08's or 2.73's or worse, it is hell on the pinion gear, as it tries to CLIMB the ring gear under heavy loads. 8.5" axles don't live long when towing over 6000's in the 90's Suburbans (and they have higher capacity sumps for more gear oil). And they had 3.42's, 3.73's or 4.10's (rare). The 9.5" axle came in the Limos, this is a heavy rear, but a very good rear end, and it will take everything you throw at it.
Recommend you have the cooling option (7 blade fan with HD clutch, extra capacity radiator, usually no less than 3 cores (brass)/2 cores (alum).
Good idea to have biggest alternator, trailering adds a lot more lights on and you NEED a trailer brake over 2000 lbs. All takes power....
As guide, the V92 Fleetwoods/Broughams were rated at 5000 lbs, had 2.93 gears with the L05. The V4P cars were rated at 7000 lbs and 3.73's with the L05. With the additional power of the LT1, they were able to drop the gear down to a 3.42, but that is it.
I wouldn't tow heavy with a THM200 4R, or a stock 700 R4/4L60/4L60E. The V4P Fleetwoods had a HD 4L60E.
If I was gearing from scratch, I would gear it to be at torque peak at desired towing speed, in the gear I can tow in. I have a 4L80E in my Suburban 454, I tow in OD, so my gearing of 3.73 is too tall to run at 65 mph and be at torque peak (well, the torque peak advertised is 3250 rpm, which is too high in my book anyway, it has cam issues...) 4.10's are much more desired, lets you slow down and tow more efficiently.
The LT1 has torque peak around 2400 rpm, so 3.42's in OD at 75 mph is running 2200 rpm, but in D at 55 mph, you come up at 2300 rpm. So Cadillac had it dead on right, torque peak at towing speeds.
Chevy had it wrong.... they installed the 454 cam retarded 7-9 degrees, so torque peak is whacked....
No speculation here. I have towed up to 10,000 pounds with a '68 limo. Used the car for scrapping other cars, so the load was always weighed (it's how I got paid).
No special equipment other than a trans cooler, and the trailer had full electric braking on all axles, checked frequently.
So, that is my experience, your's may vary.