TH400 and differential gearing

[92terminator]

i have a th400 in my 92 1500 with 30.50 tall tires (275-30-24), what gearing would you go with?? mostly gonna drive this around town and id like it to have as much grunt as possible but still be able to take it on the highway IF i had to...

open to hear your opinion.

thanks,
jorge

 

[DRAGGIN95]

Man if you want to be able to have some low end power and still go out on the highway I would stay at 3.42 or under. I have owned several truck's with 3 speed's, the worst of which had 4.10's but even 3.73's with 3 gear's suck' bad out on the highway. My last truck I had 31/10.50's on it, with 3.73's and a 3 speed trans. At 70 mph I was about 3800 rpm, just shy by 200 rpm's of redline. That sucked bad!

 

[92terminator]

your not kidding its got 3 73's in it now but its not as bad as when it had 27'' tires

 

[chevy_man]

If you stay in town I'd keep the 3.73's.

Highway, go up to 3.42s, but it's really not worth regearing if you only drive on the highway occasionally.

With 3.73's and a true 30" tire you should only be spinning 3K rpm at 75. Sure, it'll suck a little more gas, but if you wanted fuel efficiency you should have put a 700r4 back in. I got the best mileage out of my tbi 350 at 2800 rpm, so there's a lot of variables.

Man if you want to be able to have some low end power and still go out on the highway I would stay at 3.42 or under. I have owned several truck's with 3 speed's, the worst of which had 4.10's but even 3.73's with 3 gear's suck' bad out on the highway. My last truck I had 31/10.50's on it, with 3.73's and a 3 speed trans. At 70 mph I was about 3800 rpm, just shy by 200 rpm's of redline. That sucked bad!

Your speedo or tach was way off. With 31's you had to be doing about 95 to hit 3800 rpm. I'm assuming you had a lock-up converter.

 

[chevy_man]

where the hell did the delete post link go?

 

[DRAGGIN95]

No I did not have a lock up convertor, I would run 3k rpm's at 60 mph, that's the reason that truck got a 700R4, my 94 CC longbed with a 350tbi and 4L80E would run 3K rpm's at 68mph in O.D. with stock size tires.