lurch

Ok I have a dana 35 rear axle and the tag on it says 3:55 gears, but here is my question: I am running 235/75 size tires right now, and it is an automatic. At 55mph I am running 2200-2500 rpm, and it takes alot of throttle to keep it there. The previous owner had it lifted and running 35's. My question is , is it possible I have lower gears than the tag states? Is that a normal rpm to run? I have seen a few posts on people runnin 65-70mph at less rpm than I am, when I get up towards 65 I am over 3000 rpm. Oh, it is a automatic trans.

89Laredo

I would say your trans is SCREWED or you have different gears.
Most likely different gears though.. lol
Does it still lock up when it hits 45? (should be a ~500rpm drop)

IF the PO knew what he was doing, it should have 4.10s or higher in it.

mark a tire with a line you can see (metallic sharpie or something)
mark the driveshaft the same way

See how many rotations of the driveshaft it takes to turn teh tire one rotation. wont be very precise, but will give you an idea.

another way would be to take the diff cover off and count the ring and pinion gears, this is the most precise way.


OR

get ahold of the PO and ask him.

freegdr

pull the cover and rotate gears until you see numbers on the ring gear htye wii be together like this 13-43 but not the same as these this is a reference only then you divide the smaller number into the bigger one and you get your gear ratio

lurch

The tranny shifts fine, and I have tried to get ahold of th po with no luck. I will try that trick this weekend