Gears or What?

[Carl D.]

Do I Need Gears or What.

I have a 92 Ford Exp. 4.0 with 33" tires and 4:10 Gears. The truck runs great in the city, but runs like a 3 lagged Dog at hitghway speeds. The truck tops out at 65 and 2900 rpms on the highway . The truck runs great Off Road in the mountains of Colorado, but din't have much pedal left on several of the steep climbs like, Radical Hill, SOB Hill, Glacier Pass. Top speed in the mountains highway passes was 35-40.

Shoulds I install 4:56/4:88 Gears or try something else.

HELP!!!!!!!!

 

[mrboyle]

The lower gears will help a lot.

 

[Robb]

Is it normal for an X with 33s and 4.10s to top out at 65?

Robb

 

[Jason_25]

Heh I tend to think you may have some engine problems if you can't go faster than 65. Maybe time for a tune-up?

 

[Gary Steeber]

Sounds like your not getting full throttle. Check the carpet under the gas pedal it could be restricting the padal. Or Possibly your throttle cable is hanging up and not opening the throttle body all the way.
With my 33's and 4.10 gears I have no problem getting up to 80mph with my rpm exceeding 3000.

 

[Carl D.]

I agree, this is insane. I just had a Jasper 4.0 and the 4:10 gears installed before taking this trip to Colorado and had nothing to compare with. What had me confused was that the X ran fine when off roading in the mountains and seems to run ok for city driving, just no top end speed. May sound crazy, that why I'm confused.

 

[X24]

How hard is it to change the gears? I want to go up to a 4.10.

 

[Carl D.]

It's not hard to change Gears if you have the correct tools (i Don't). I sent mine to a 4 Wheel Drive Sop locally. I paid about $1200.00 for the gears and the install, unfortunatly I didn't get go low enough with my gears. Make sure you get the correct sixe or you'll be doing it twice like me.

 

[Robb]

Carl,
What I was trying to shoot at in my previous post is that problem with not going over 65 is not a gear problem. IMO, you have the proper gear ratio in your pumpkin for 33s (that point is debatable between 4.10s and 4.56s). Your setup is the setup I am looking to do in the next few months. There are bunches of members of this site that run 33s with 4.10s, and I have never heard of the problem of topping out at 65mph @ 2900 rpm.

Like Jason_25 mentioned earlier, it may be time for a tune up. I think your problem may lie in an engine power problem rather than in a power tranfer problem.

Robb:smoke:

 

[Carl D.]

Robb

I think I will try a complete tune up as well as a K&N Filter System, Throttle Body Spacer and maybe a Granelli (?) Air Sensor.

This shoud do something.

Thanks

 

[Carl D.]

PS:

The Superlift Suspension really works great. I received numerous compliments from other Off Roaders in Colorado who were very impressed with it.

Also remember to Air down wehn rock crawling, it cost me a tire, side wall blown out by rock. Oh well, live and learn.

 

[coolchris]

if you get lower gears (4.56, 4.88 etc.) it will make your low end better and hi end speed even worse. if you get higher gears (3.73, 3.55, etc.) it will make yoru low end week but it will be able to have a higher top end speed. BUT, i dont think this problem is related to gearing because 4.10 with 33's is a normal setup thats pretty close to stock. so if i were you i wouldnt change the gears, they are good.

 

[Jason_25]

Originally posted by Carl D.
Robb

I think I will try a complete tune up as well as a K&N Filter System, Throttle Body Spacer and maybe a Granelli (?) Air Sensor.

This shoud do something.

Thanks

Don't spend your money on all that crap just yet. You need to fix what's wrong before upgrading. Mine doesn't have any of that stuff on it and will easily reach 90-95 mph and I have 3.73 gears. Here are my recommendations for a full 4.0 tuneup.
1.Change oil and filter (Motorcraft Fl1A filter and possibly synthetic oil)
2.Run a whole bottle of seafoam through the engine
3.Run a whole bottle of seafoam through the gas tank
4.Replace plugs and wires (motorcraft double plat plugs and your choice of wires)
5.Clean IAC.
6.Check for vacuum leaks
7.Check for adequate fuel pressure
8.Clean/Replace MAF
9.Replace tranny fluid and filter
10.Clean throttle body, upper intake, throttle plate, and intake pipe/air filter housing with carb spray
11.Replace TPS
12.Replace Oxygen sensors (you have only one)
13.Replace Air filter
14.Replace fuel filter
15.Replace PCV valve
16.Throttle Cable fix

Do all that and I guarantee your performance will improve drastically.