Novak Conversions Jeep Wrangler TJ engine mounts

Dana 35 Swap

fiirechief467

fiirechief467

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My Wrangler was/is a stripped down X with 27.7” tires on 15” rims, 6 cyl, 5 speed, 307 gear. I raised the suspension 3” and had 33” X 15” tires installed. Most times I cannot get out of 4th gear due to the change in tire size. It runs much faster in 4th (70 mph @ ~2700 rpm). In consideration of re-gearing I’m drawn to the 8.8 Ford swap to replace the rear Dana 35. Doing internet research there are some questions I was hoping some might have input to help me navigate the best solution. I don’t plan to rock crawl or any kind of competitive jeeping. I would like to do confident trail riding and travel to hunting locations, as well as the occasional 80 mile round trip to work and back.

1. Are 8.8 rear ends still available in the junk yards?

2. Trying to decide on the correct gear ratio I’ve seen a You Tube video that uses a formula for determining the needed ration for a tire size change: new tire size / factory tire size X factory gear ratio. My Jeep would be 33”/ 27.7” X 3.07 = ~ 3.66, or most likely 3.73. However, some threads on this site recommend a 4.56 gear for 33” tires. Which will provide the best compromise for my setup? Although only two gears are available between 3.73 and 4.56, it seems like a big jump in the ratio.

3. Regardless of an 8.8 or a Dana 44, I’m looking at lockers, since the gears need to be changed anyway. Again on You Tube John Currie was marketing his JK (or whatever model it was) with an E-Locker in the rear and a Detroit locker in the front. Does to Detroit locker affect normal turning radius when not locked in? Will the front Dana 30 handle the Detroit locker?

4. If I could find an 8.8 with 4.10 gear (which would be a limited slip with 31 spline axles) would I be better off going with the 8.8 and 4.10, instead of #3 above? Certainly the cost would be quite a bit less.

Thanks for taking the time, if you made it to the end of this epistle. Any comment and suggestions are welcome, especially the credible ones.
 
1) YES.

2) Google grim Jeeper and play around with the calculator.

3) No, yes.

4) again, it’s your Jeep, play around with the gearing calculator on GrimJeeper.

You’ll love it geared a little lower than you think it should be. Lot of folks here wish they had gone deeper the first time around.

You’ll be fine keeping the Dana 35 rear if youre planning to using it like you mentioned. No real need for a rear end swap unless the cost is much less going to to the 8.8 compared to building the Dana 35. The 8.8 does have the advantage of the disc brakes as far as ease of maintance is concerned. But a Dana 35 can be disc brake swapped.
 
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Ton of 8.8s around the pick and pulls out of explorers. But if you are going to have to regear the front to match i would just stick to the 35 rear. Weld the tubes to pumpkin and add a truss to the front axle and it be good to go. Beat on same setup with 35s and its not bad. Just gotta be careful not to bend the front or rear up or the lockers will help chew axle shafts up. 4.56 gears with spool in rear and selectable front locker pretty hard to beat for road and trail use.
 
fiirechief467 said:
3. Regardless of an 8.8 or a Dana 44, I’m looking at lockers, since the gears need to be changed anyway. Again on You Tube John Currie was marketing his JK (or whatever model it was) with an E-Locker in the rear and a Detroit locker in the front. Does to Detroit locker affect normal turning radius when not locked in? Will the front Dana 30 handle the Detroit locker?
Click to expand...

A lot of folks here recommend having selectable locked in the rear and the auto locker in the front.

I have TJ Dana 44 rear, with ECTED e-locker.
Dana 30 HP (from Cherokee, if is bolt in swap) with Yukon Grizzly (same thing as Detroit.
In TJ transfer case, when in 2High, the front is simply disconnected, and I simply don’t feel the presence of Grizzly. Never heard a sound from it in 2High.
In 4High or Low, it locks perfectly fine.
I am in Texas and my TJ is daily driver, so 4WD is not used on concrete or asphalt whatsoever. If you are in the area where you plan to 4WD on roads, then Detroit might be a bad idea, go for selectable only.
 
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As for gearing, the right gears depend on which gearbox you have. I have 4 speed automatic, and for me the 4.56 is correct gear for 31inch. For your 33s, and 5 speed, you will need 4.56 at least.
In my opinion, the ideal ratio is having 2500RPM or higher in overdrive. 2500RPM is perfect match for 31s, you will need 2600RPM for 33s.
Use grim jeeper, it is the best source.

BTW, my axles with 4.56 gears came from 5 speed TJ with 33s. He sold me the axles and upgraded to JKR axles.
 
fiirechief467 said:
2. Trying to decide on the correct gear ratio I’ve seen a You Tube video that uses a formula for determining the needed ration for a tire size change: new tire size / factory tire size X factory gear ratio. My Jeep would be 33”/ 27.7” X 3.07 = ~ 3.66, or most likely 3.73. However, some threads on this site recommend a 4.56 gear for 33” tires. Which will provide the best compromise for my setup? Although only two gears are available between 3.73 and 4.56, it seems like a big jump in the ratio.
Click to expand...

I have a 4.0 with 5-speed on 33x12.50x15 (32" actual tire height) I'm currently geared 4.10, and it works well in my relatively flat area. I run 5th gear on the highway no problem, but I'd honestly like to be geared down to 4.56 as when I go to the mountains I find it just slightly under geared. So for a street driven Jeep I suggest going with 4.10 or 4.56 with 33" tires, depending on your local terrain.
 
I've not seen a lot of ring gears break with the Dana 35, it's almost always the axle shafts. Like @Fouledplugs said, a Dana 35 will work well with your desired setup, but you'll need to do the Super 35 kit. This will give you 1541 30 spline axles, which you can pair with an Eaton E-Locker or ARB. What most don't think about with the Dana 35 is that it's lighter and provides slightly more clearance at the differential than a stock 44 or 8.8.

As for the front, you're not going to want a Detroit locker, unless you've got a hub kit. You could go with an auto locker, like a Torq Locker, but a selectable is really the way to go. As has been said, gearing would be 4.56 with a 33" tire. If you think you'll go to a 35" tire, 4.88.

https://wranglertjforum.com/threads/ford-8-8-axle-swap-info-faq.66/
https://www.revolutiongear.com/prod..._tj_cherokee_xj_30_spline_upgrade_super35_kit
https://www.torqmasters.com/torq_locker_tl_13027_dana_30
 
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Upgrade/strengthen your Dana 35 with a Super 35 kit from https://www.revolutiongear.com/prod..._tj_cherokee_xj_30_spline_upgrade_super35_kit

That kit removes the Dana 35's weak point by replacing its carbon steel 27 spline axle shafts with 1541H heat treated 30 spline axle shafts that are slightly stronger than a Dana 44's carbon steel 30 spline axle shafts. It's more than up to 35" tires on even very (!) tough trails. To that kit you then add your choice of 30 spline locker like an Eaton E-Locker, ARB Air Locker, or Detroit Locker.

At the same time as the Super 35 installation regear your axles to 4.56. That combination will work VERY well. And the Super 35 would be a hell of a lot easier than replacing the axle. I'm also no fan of the Ford 8.8 axle. It's pumpkin is huge reducing ground clearance and its pinion shaft is offset to the side making the rear driveshaft into a sideways angle in addition to the normal up-down angle.

There are a LOT of Super 35 kits installed and those that own them love them. Only those who don't know WTF they're talking about will say not to install them.
 
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Fouledplugs said:
1) YES.

2) Google grim Jeeper and play around with the calculator.

3) No, yes.

4) again, it’s your Jeep, play around with the gearing calculator on GrimJeeper.

You’ll love it geared a little lower than you think it should be. Lot of folks here wish they had gone deeper the first time around.

You’ll be fine keeping the Dana 35 rear if youre planning to using it like you mentioned. No real need for a rear end swap unless the cost is much less going to to the 8.8 compared to building the Dana 35. The 8.8 does have the advantage of the disc brakes as far as ease of maintance is concerned. But a Dana 35 can be disc brake swapped.
Click to expand...

Here’s what 4.56 gears will do for you. I love mine!

10B331D5-88E7-413C-A530-BF79E767E57D.png
 
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TexasTJ2004 said:
A lot of folks here recommend having selectable locked in the rear and the auto locker in the front.
Click to expand...

More like a lot of folks are looking for a cheaper alternative to lockers, and as a result they always bring up lunch box lockers for the front.
One is all around a good option, and the other requires a weighting in some very important pros and cons. This are two different things.
 
eastbloc said:
More like a lot of folks are looking for a cheaper alternative to lockers, and as a result they always bring up lunch box lockers for the front.
One is all around a good option, and the other requires a weighting in some very important pros and cons. This are two different things.
Click to expand...

When I mention autolocker, I mean a full size locker like Detroit or Grizzly. It is not really a cheap option, because installing a Detroit or Selectable is almost the same cost from labor perspective. Form the part perspective, Detroit is cheaper than selectable, but not like dirt cheap.
I would not install lunchbox stuff, as I suspect that it is not good enough for large tires to work reliably.
 
Last edited:
eastbloc said:
More like a lot of folks are looking for a cheaper alternative to lockers, and as a result they always bring up lunch box lockers for the front.
One is all around a good option, and the other requires a weighting in some very important pros and cons. This are two different things.
Click to expand...
I constantly suggest lunchbox lockers for the front axle, it's a good lower-cost true locker upgrade that is very good for most wheeling situations. Especially when their rear axle is a Dana 35 and they aren't financially up to buying a Super 35 upgrade. I'd never recommend one for the rear or for areas that have icy conditions however. I really liked the front No-Slip lunchbox locker in my previous TJ.
 
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fiirechief467 said:
My Wrangler was/is a stripped down X with 27.7” tires on 15” rims, 6 cyl, 5 speed, 307 gear. I raised the suspension 3” and had 33” X 15” tires installed. Most times I cannot get out of 4th gear due to the change in tire size. It runs much faster in 4th (70 mph @ ~2700 rpm). In consideration of re-gearing I’m drawn to the 8.8 Ford swap to replace the rear Dana 35. Doing internet research there are some questions I was hoping some might have input to help me navigate the best solution. I don’t plan to rock crawl or any kind of competitive jeeping. I would like to do confident trail riding and travel to hunting locations, as well as the occasional 80 mile round trip to work and back.

1. Are 8.8 rear ends still available in the junk yards?

2. Trying to decide on the correct gear ratio I’ve seen a You Tube video that uses a formula for determining the needed ration for a tire size change: new tire size / factory tire size X factory gear ratio. My Jeep would be 33”/ 27.7” X 3.07 = ~ 3.66, or most likely 3.73. However, some threads on this site recommend a 4.56 gear for 33” tires. Which will provide the best compromise for my setup? Although only two gears are available between 3.73 and 4.56, it seems like a big jump in the ratio.

3. Regardless of an 8.8 or a Dana 44, I’m looking at lockers, since the gears need to be changed anyway. Again on You Tube John Currie was marketing his JK (or whatever model it was) with an E-Locker in the rear and a Detroit locker in the front. Does to Detroit locker affect normal turning radius when not locked in? Will the front Dana 30 handle the Detroit locker?

4. If I could find an 8.8 with 4.10 gear (which would be a limited slip with 31 spline axles) would I be better off going with the 8.8 and 4.10, instead of #3 above? Certainly the cost would be quite a bit less.

Thanks for taking the time, if you made it to the end of this epistle. Any comment and suggestions are welcome, especially the credible ones.
Click to expand...

Do not pay attention to that video. It is based on very flawed logic. You want no less than 4.56. 4.88 would be even better.
 

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