Gear ratio

Reply Subscribe

Thread Tools

Search this Thread

Feb 10, 2009 | 06:10 PM

k_conner

Thread Starter

Senior User

Joined: Jan 2008

Posts: 108

Likes: 0

Gear ratio

Hey everyone, I have a 97 F350 PSD. Everything is stock except the tires. I have never pulled anything before until last fall. It didnt perform as I thought it should. I got under the truck to check the tag to see what my gear ratio was and there was no metal tag. Is there another way to find out what my ratio is? Thanks...

Feb 10, 2009 | 06:40 PM

Cuda_jim

Post Fiend

Joined: Oct 2003

Posts: 5,903

Likes: 1

From: MICHIGAN

Sounds like you have 3.55 gears or very tall tires. You can check the door sticker for the ratio...assuming the gear hasn't been changed. The only way to know for sure is to open it up and count the teeth.
.
.
.

Attached Images

Certification Lable on door.pdf (22.7 KB, 126 views)

Feb 10, 2009 | 07:10 PM

k_conner

Thread Starter

Senior User

Joined: Jan 2008

Posts: 108

Likes: 0

Thanks Cuda

Your right. After checking it said axle 39. from the chart you provided the ratio is 3.55. My tires are oversized at 33 x 12.5 x 16.5. The combination is probably not good. however, I still think it lacks power. I have done the map sensor check of unplugging and it made no difference. I have also cleaned out the fuel filter bowl and screen. Should I check the fuel pressure next?

Feb 10, 2009 | 10:18 PM

c00nhunterjoe

Lead Driver

Joined: May 2007

Posts: 8,608

Likes: 13

From: Belair md

is the truck bone stock? if so check for a clogged cat. they are doggy stock to begin with, and 33's on 355's doesnt help

Feb 10, 2009 | 10:23 PM

jimwilsonmasonry

Elder User

Joined: Jan 2008

Posts: 644

Likes: 0

From: indy

yep my cat was clogged on mine when i bought mine you couldnt hardly see daylight through it -it had 240000 miles on the ticker

Feb 10, 2009 | 10:27 PM

k_conner

Thread Starter

Senior User

Joined: Jan 2008

Posts: 108

Likes: 0

CoonHunter

Quote:

Originally Posted by c00nhunterjoe

is the truck bone stock? if so check for a clogged cat. they are doggy stock to begin with, and 33's on 355's doesnt help

I bought the truck used but, yes, as far as I can tell it is bone stock except for the tires. No Mods that I can see. What do I do to check for the clogged CAT? Also I took the boot off the turbo and checked it out and everything looks good. No scarring or chewed up teeth. Spun very well. I checked the hose from the MAP as well but it wasnt clogged. I do have a small amount of fuel in the valley, which i dont know where its coming from. I replaced the pump last year. Thanks for your help. If you can tell me how to check that CAT i'd be grateful. Also if it is clogged should I replace or what are my options? thanks again...

Feb 10, 2009 | 10:55 PM

c00nhunterjoe

Lead Driver

Joined: May 2007

Posts: 8,608

Likes: 13

From: Belair md

best way to check it is remove it, 99.9% of people dotn run the cat, very restrictive even when its not clogged and contributes to high exhaust gas temps.

check the banjo bolt on the back of the fuel pump to make sure its tight and not seeping past the washer.