iam thinkin of puttin 3:55's in my 03'..anyone got them in theres? and how does it run, what about MPG?

 

Good luck trying to find 3.55's for our AAM 11.5" axles. So far only 3.73 or 4.10 for the 11.5". Could upgrade to larger diameter tires to offset the ratio.

MikeyB

 

I have 35"Toyos w/3.73 and a 6 speed. Needed the clearance.

No tow, they work great. Tow on a grade with wind in your face and you are in fifth gear.

Mpg is about the same, probably due to rolling resistance.

As a side note, had the tires siped. Phenomenal on ice and hard snow.

 

ctd
I have them in my 01.5. Fuel mileage is 14 to 15 towing and the best I've had on open hwy is 20.6.

Gary

 

I also have a 01.5 with 3.55 and a NV5600 and stock tires towing in 6th seems to run the EGTs up if you try and run 55 (rpm to low) but at 65 its ok I pull a 12k and heavyer trailers and see 10-12 mpgs at 65 mph. unloaded i get a solid 24 mpg if i hold 62 mph, seems to be a sweet spot. if i go 65 or up it drops to 19-20 .over all i am very happy with the gears and the whole truck.

 

1990 W250 stock727 high miler heavly bombed
2001 drw 5spd fass,fuel boost,pyro, smartyRV275s
2001 2500 HO 6spd 4x4 all the gages.banks brake & mad.ecm mach1.6s fass,SBC 4" turbo back exhaust
90 D350 727 3200 GS. sold but i still service it
92 W350 stock
90w250 A/TBombed GS high miler
91.5 w250 4x4 5spd 32gs tweaked 5"stacks
97 3500 4x4 auto 3kgsk plate&afc forward 4"ex.afe
timing at 15* gages
98 12v4x4 plate afc forward gauges
99 f250 PS chipped
83 chevy sub 6.5td hot rod pump


I think you need one more truck.

 

Can anyone tell me what came out stock in my truck? I looked at the VIN number system and didn't see an axle code in there. I guess I should research a little more. Anyone know without me doing all that reading?

 

Does anyone know if you can get 3.55 gears for a 2004.5 48re auto?

Thanks.

 

No, you cannot. AAM has only released 3.73's and 4.10's for the 11.5" rearend so far-end of story until they or someone else makes other ratios.

 

Nope. Upgrade your tires to 285/70/17 will change your ratio to around 3.60 if you have 3.73s. Close enough.

MikeyB

 

look inside the glove box, theres a tag, if its not stated , you have 3.73 because they are standard. It will say 4.10 if it has them because 4.10 is optional

 

Thanks, AirGrabber. My glove box states 3:55. I'd sure rather have the 3:73's. I think 4:10s would be too low for everyday, but with my 285's on, it sure takes off the get-up-a-go! Like stated before, it is hard to pull anything in 6th without running the EGT's out the roof (stock that is). I haven't pulled much with the juice module installed, but I'm sure my new II PS62/14 turbo this weekend will help with that. Anyone wanna trade 3:55's for 3:73's???

Now that I have confirmation on my ratio: to answer the original question, DON'T DO IT! I wouldn't. Who the heck needs to go 120 mph? I'd rather be able to get from 0 to 80 in half the time than to be able to run 120 mph at 2000 rpm (exaggeration for those who heckle).

 

I just look at cruising RPM. On the highway my truck sits at 2100 to 2300 rpm in 6th gear. I did some rough math and I think bfg 315's will only drop me about 180 rpm and add rolling resistance. 355 gears will drop me about 350 rpms wich is about right without the extra resistance.

I've had 355's in the last 4 trucks and always wanted 373's. Now that I have 373's I'd give anything to have 355's again.

 

Well, I can't see where you're located or if your truck is a 4x4, but if you are close, you know how, and it is, come switch them for mine. I'd love to have 3:73's. I pull trailers ALOT and don't mind the extra RPM's for those long hills.

 

No can do.

Your '02 has Dana axles and the '04 has American Axles. No part interchangability between the two.