before you go worrying 'bout anything else......REPLACE THE 35C WITH A 44!

I was thinking about a 44 or a Ford 8.8? Not sure which way to go with that? I have heard the Ford 8.8 is the cheapest and I would get to upgrade to disc brake in the rear. Anyone ever done this conversion on and 89YJ?

Thanks

Check out:

www.jedi.com/obiwan/jeep/ford88.html

Overdrive tranny? 5 speed? go with 4.56 and look at the facts, a three speed auto vs a 5 speed manual?

3 speed auto: 4.10 with 33" tires.
5 speed manual: 4.56 with 33 or 35" tires.
For the last 6 years...
I install, on average 5 gear sets a week almost all in jeeps or custom axles to be swapped into jeeps, to date I have never had any customer say to me..."those 4.56 gears are too low, I wish I had 4.10s"ROFLOL. However, I have heard from folks who insisted that I install 4.10s say "god I wish I had listened and had you install 4.56 or even 4.88s.
Two or three gear sets a month for the 10 years prior to that.

If you listen to one fellow with one jeep who suggests to run simply what they are running in their own rig is not doing the smart thing.

You are not creating "crawl ratio" by changing from 3.54 (example) TO 4.88, if the tires went from oe to 33 or 35s.
What you are doing is getting the gear to cam and engine rpms all back matched where they are close to stock performance. Tire height is not the only factor in determining ratio, rolling resistance, air drag and weight are factors also. So if the best gear for 33x12.5 tire and oe engine is a 4.10 add the other factors and 4.56 looks much better. One other factor is "the bug" once you wheel with 33s the 35s are not to far away. Another reason to go one step past the "ideal" ratio.

SD

Thanks for the responses,

I'm looking a weighing all my options for the gears that I'm going to install in my Jeep. IÆm asking a lot of fellow four wheelers that have already gone through the trial and error of using many different gear setups. Remember this is still going to be a daily driver and it will see freeway use every day (about 16 miles round trip to work and back).

YouÆre right; the one thing I donÆt want is to get a gear setup that IÆm not completely happy with? If I go with a 4.56 setup is this going to max out my jeep around 65 to 70 MPH? (Personally the freeways that I drive are so grooved from traffic that 60 MPH in my jeep now is scary) and what is it going to do with my gas mileage? If I drop one mile per gallon or so I could live with that, but if we are talking 3-5 miles per gallon then I probably would sacrifice the 4.56 for 4.11?


Anyone no how to figure the miles per-gallon with gearing?

Thanks,

Josephelk

Joe you need to remember lower RPM's don't mean better milage! If you are happy with your milage now.. then you need to keep the rpm's after the gear change to what you have now or MORE! Since the tires will be harder to spin you will need a few more R's to roll em.
The most common problem I see with installing larger tires is the engine lugs and a lower tranny gear is needed to simply get around town. So you run around in 4th and never see 5th again.
When going up to HUGE meats many more R's will be needed to keep the same or equal "feel" to the ride.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

This might be one of those stupid questions but I will ask it anyway? If I put a Ford 8.8 with 4.10 gears in the rear of my 89YJ and keep my DANA 30 front and install 4.11 am I going to have issues? Or are they close enough to matching that I will wonÆt have problems.

Please don't everyone heckle me at once, take your turns.

Good choice...do it!
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Just a personal note, I,ve got an 84 CJ7 that used to have the 258 in it with 4.10,s and a 3 speed TF999 auto running 35 BFG,s. On the highway it would rev at 60mph to 2400rpm. Against a headwind anything faster than 60 was impossible and it was always floored which doesn,t do much for mileage. Off road required low range in sand or rock just to be able to drive around. I have now installed a 304 V8 and expect the extra torque of the 50 cubic inch bigger motor to help a bit. Seriously consider the 4.56,s if you want to run 35,s.

Thanks,

In Vancouver someone is party out a 1996 Explorer with a 302 engine 8.8 rear end and we cannot match any numbers on the housing to find out what gears are in it. The VIN is 1FM0U35T5TUD31890, other numbers on the axle area S619A-R and 73886E03 if this is 4.10 Gearing I would buy it. How do I find out what the gearing is?