1990 with 3.9 / A500 towing 7-8k , what would be the average lifespan at this rate ?

 

Don't use the overdrive when towing or you will have next to no lifespan. I would put on a trans cooler if you don't already have one.

 

Overdrive stays off and it does have a small cooler.

 

Make that a larger cooler; my 1988 has a Hayden 679 I use for a transmission cooler.

Remember the brakes barely made federal safety standards in 1990; do NOT push them!

Pay careful attention to the GVWR on your truck; stay under it, and remember to use the proper tires to maintain that!

(If it says "LT215/75R15D" then a set of 225/60R15 P series won't do! You could use, say, P235/75R15 XL tires, though ... )

RwP

 

Average lifespan? No stats for I know on that one. I wouldn't make a habit of towing that much. It's dangerous for you and others on the road. Make sure your trailer brakes are operating perfect.

 

Youre going to kill that truck in short order. Even v8 magnums aren't made to carry that much. I mean maybe here and there on flat ground for a few miles, you might be fine. But I'd honestly be surprised if it lasted 2 weeks with repeated driving with a load like that.

 

I try not to tow very often. And I won't go over 30 mph even with trailer brakes as I've noticed the trucks stock brakes aren't the best. And does anyone know of a way to break 13 mpg ? That's all the truck gets by itself. Also the dealer the truck was bought from when new said the powertrain is capable of pulling that much , but the brakes wasn't capable of stopping it.

 

It won't get very good at 30MPH; what I'd do to maximize it while towing would be to get stiffer rear gears in (for instance, if it's a 3.55 now, try a 4.10 or so). That should put it better into the power band.

But gas mileage will suck on these trucks when you're doing much off of 55MPH.

RwP

 

I was referring to the truck only gets 13 mpg on the highway. It was a Dana 70 with a 3.55 posi.

 

w/ that is a Helluva swap. a Dana 70? Yikes! That is 1-ton full size truck territory....