Dodge Ram Cummins Diesels and Mopar banner

1 - 12 of 12 Posts

·
Registered
Joined
·
108 Posts
Discussion Starter · #1 ·
I just bought a 12.5' tent trailer. Let me tell you IT IS GREAT! But while climing hillsI got down to around 35 MPH. Kind of embarrassing when a Nagasaki Nutbucket passes you carrying a much heavier load. Soooo I guess my question is with my tires being 31x10.5r15 and gears are ? (I can't find a tag), what gears would help with the occasional weekend towing and not make the engine sound like its comming apart at 65?
Thanks in advanceb
ZOMBIE
 

·
Super Moderator
Joined
·
13,985 Posts
You gotta check what gears you have first. Or we may be able to make an estimate based on your speed and tire size. i would think 3.73 gears would be good for you.
 

·
Registered
Joined
·
2,137 Posts
3.23 is really common on the pre-overdrive RC's... you'll have to look for the ratio tag, count tire/pinion turns, or get numbers off your ring gear when you have the diff cover off.

Isn't 3.73 is the one ratio you can't get for a 9.25"? I'd suggest 3.92 over 3.55 because too small a change usually isn't very satisfying.
 

·
Registered
Joined
·
13,252 Posts
35 ? comming apart ? ( reving very high?) how steep of a hill?? 12.5 tent trailer ? what does it weigh ? are its brakes dragging ? what state of "tune" is your 86 360 ? it should be a carbed motor NO ? 31's should work fine with stock gears.
 

·
Registered
Joined
·
13,252 Posts
what transmission gear is it "in" when it slows to 35 ?
 

·
Super Moderator
Joined
·
13,985 Posts
3.23 is really common on the pre-overdrive RC's... you'll have to look for the ratio tag, count tire/pinion turns, or get numbers off your ring gear when you have the diff cover off.

Isn't 3.73 is the one ratio you can't get for a 9.25"? I'd suggest 3.92 over 3.55 because too small a change usually isn't very satisfying.
Yup, forgot about that. 3.90 would have to do.
 

·
Registered
Joined
·
28,354 Posts
You gotta check what gears you have first. Or we may be able to make an estimate based on your speed and tire size. i would think 3.73 gears would be good for you.
BLASTFAMY , those are "chevy" gears , 💣 he probly has the standard gears of 3:21's and he would need any of the DODGE gears of 3;55 - 3;91 or 4;10

NOTE / we HAD a tire & gear ratio calculator but its gone now

with 31's and towing l,d go 3;91's
 

·
Registered
Joined
·
7,004 Posts
35 ? comming apart ? ( reving very high?) how steep of a hill?? 12.5 tent trailer ? what does it weigh ? are its brakes dragging ? what state of "tune" is your 86 360 ? it should be a carbed motor NO ? 31's should work fine with stock gears.
I think he was referring to if he went too low it would be revving too high.

It's a conundrum. Low gears are nice for power and towing. High gears are nice for mileage and cruising down the freeway. But... with a 3 speed transmission your stuck with compromise.
I agree with the 3.91.
I went with a 4.11 (Sorry Dodgeboys. I've been running a 9" for over 44 years now) knowing I was pushing the low gear "envelope". It was low... but it was awesome... except on the freeway. I also knew I was going to do a Gear Vendors install soon. Which solved the low gear problem for awhile until I evolved away from that system.
 

·
Super Moderator
Joined
·
13,985 Posts
BLASTFAMY , those are "chevy" gears , 💣 he probly has the standard gears of 3:21's and he would need any of the DODGE gears of 3;55 - 3;91 or 4;10

NOTE / we HAD a tire & gear ratio calculator but its gone now

with 31's and towing l,d go 3;91's
Well they're just not 9 1/4 gears. You can get 3.73 on Dana axles (and Furds too).
 

·
Registered
Joined
·
13,252 Posts
I have trucks with 323s and 410's and both will run up a highway hill grade at better than 35 mph , with a 318 and a "tent" trailer in tow . Mine you there are a few dirt town roads where your in 1st gear empty ... so I ask again what gear is the trans in when you can't make over 35 ? does the throttle not fully open ? what type of fuel system IS it ? a 4 bbrl carb?
 

·
Registered
Joined
·
108 Posts
Discussion Starter · #11 ·
It kicks down to 2nd. Just your standard 360 4bbl. It runs just fine on the flat with trailer and up the same hills without.
 

·
Registered
Joined
·
13,252 Posts
two things come to mind , BUT not being there hearing it I cannot say with much surety . A 3 speed 727 behind a 360 4 brl should be able to pull a fairly light trailer with out TOO much problem .It was when the 518/46rh came into use and you were in overdrive problems started ) I'm wondering about the tune and stuff like does the 4 barrel work , AND is the trans downshifting too soon . ( throttle pressure too high ) when your "pulling " this hill , and your doing 35 in second gear , is that "all she's got?" where's your foot ? the engine CAN do the same rpm on a flat even if its running off JUST the 2 primary's but when you come to the hill it needs more fuel mix ... because it needs more power . I'd put a 2 brl on G/F's 360 raised big tires 488 gears (?)435 4 speed " bad ass truck ", it was fine untill she went to pass on a highway , boy did I catch do-do over that , it didn't breath enough anymore when you floored it it came up gradgually because it was allready wound up and using all that 2 brl bbd could deliver .... LOL
 
  • Like
Reactions: neil4224
1 - 12 of 12 Posts
Top