Rear End Ratio

Reply Subscribe

Thread Tools

Search this Thread

Dec 18, 2004 | 07:30 AM

eldomike

Thread Starter

Junior User

Joined: Jun 2003

Posts: 53

Likes: 0

From: Tenn

Rear End Ratio

I have a 1991 E350 High Top Van with the 7.3 and E40D tranny....it has 3.55 rear gears....I bet this thing will run the Ton but since I pull a trailer and would rather run 60-65 I'm thinking I should look at getting a 4.10 or something rear end...I'd like to be able to pull the hills better...watcha think?

EldoMike

Dec 18, 2004 | 08:47 AM

ditch witch

Senior User

Joined: Apr 2003

Posts: 198

Likes: 1

From: Kansas

"....I bet this thing will run the Ton but since I pull a trailer and would rather run 60-65 to pull the hills better...watcha think?"

I'm missing something here. Rephrase your question and you'll probably get an answer that will help ya.

Dec 18, 2004 | 08:51 AM

eldomike

Thread Starter

Junior User

Joined: Jun 2003

Posts: 53

Likes: 0

From: Tenn

hmmm....sorry.
My van will run high speeds but with little power....would like to have more pulling power for hills..should I get a 3.77(?) or 4.11?

Dec 18, 2004 | 09:05 AM

ditch witch

Senior User

Joined: Apr 2003

Posts: 198

Likes: 1

From: Kansas

I've got a PU, not a van, however same problems when it comes to gearing. My truck had 4.10's and it would pull anything. BUT- I only use it to pull a trailer maybe 5-10% of the time. AND, I never used 1st gear to start out. (I do have a 4 speed T-19, as opposed to your auto). A month or so ago I switched out the rear for 3.54 L/S. It still has plenty of torque, and I still don't need 1st if I'm empty. Engine runs much slower, cab is quieter, fuel ecomony is up--everything I was wanting. And, Oh, I don't get stuck in a heavy dew!!

If you want a happier medium go for 3.73.

Dec 18, 2004 | 12:28 PM

Dave Sponaugle

Post Fiend

Joined: Nov 2003

Posts: 21,285

Likes: 15

From: Nutter Fort, WV

eldomike, with 3.55 rear end gears and 31" tires you should be running 117 MPH at 3200 in OD.
If you drop it to 4.10 gears you will still be able to see 101 at 3200.

At 2000 RPM you should be running about 73 MPH with what you have.
4.10 gears will put you at about 63 MPH at 2000 RPM.

Dec 18, 2004 | 02:45 PM

eldomike

Thread Starter

Junior User

Joined: Jun 2003

Posts: 53

Likes: 0

From: Tenn

I have 31" tires...yep, that sounds about right...believe I'll go with at least some 3.78's...

EldoMike

Dec 18, 2004 | 03:14 PM

patriottow

Freshman User

Joined: Nov 2004

Posts: 41

Likes: 0

From: omaha ne

I have 90 F350 7.3 with 4/10 rear 16 inch tires .2000 rpm=63 mph =13 mpg.I tow cars all dat and found the 4/10 to be great!Milage sucks but i can pull any thing.Fuel prices in Omaha Ne is 2.06 now and have been 2.38 a gal and i have thought about changing gears if prices go up.