Traction Improvement Devices

[85AmCfreak]

Now that ya mention it I was thinking of using the 8.25 or the D44 as a replacement the only thing I was running into was the gear ratio, I really want to try the XJ's 3.55 ratio in an eagle............. anyone ever try it?

[Sunny]

   If the car isn't staying stock I'd put a D35, Chrysler 8.25 or D44, from a XJ Cherokee, in it. 

If you are pulling it anyways, I'd just go with a D44.
D35's are relatively weak.
I've seen plenty of them break on trails.
Especially running any oversized tires.
It's a pretty well documented fact on most jeep forums.
The axles on them are just way too thin to be any good.

[standup650]

   If the car isn't staying stock I'd put a D35, Chrysler 8.25 or D44, from a XJ Cherokee, in it. 

If you are pulling it anyways, I'd just go with a D44.
D35's are relatively weak.
I've seen plenty of them break on trails.
Especially running any oversized tires.
It's a pretty well documented fact on most jeep forums.
The axles on them are just way too thin to be any good.

I agree 100%! You can build the others but the cost isn't worth it. D44 is a great axle. I had it in a s-10 blazer with a 305 and 35inch swampers on it and i broke all sorts of stuff but i never broke my used junkyard d44 axle. but then again i always run cheap u-joints so they are my weekest link on my drive train.

[doc65]

Now that ya mention it I was thinking of using the 8.25 or the D44 as a replacement the only thing I was running into was the gear ratio, I really want to try the XJ's 3.55 ratio in an eagle............. anyone ever try it?

People have done it and the factory used that ratio, with the 4 cylinder's though their math rounded it to 3.54, you can definitly get the 8.25 in a 3.07 or a 3.55 (as I have both), which pair well with a 4 cylinder 3.54 frontaxle or an optional 3.08 front axle

[carnuck]

I have an 8.25 with 3.07 going into my Eagle wagon soon. The D35 would've been fine because unless you are running big tires or seriously offroading, it handles quite a bit. I still haven't killed mine with 33" tires and rolling up on 200,000 miles in my MJ.

[mach1mustang351]

I think I have decided on doing a D35 swap with 3.55 for the rear but I still need the illusive 4cyl front axle.  I will keep looking.  Any leads appreciated. 

[85AmCfreak]

Anyone ever use the 3.55 with a 6 cylinder?? I know it must scream on the highway.....

[carguy87]

I have the 3.55 axles on my Wagon, with 258, 3spd. auto TF998.  I swapped in a TF998 with lock-up because it scared me soo much down the highway.  With 235/75 R15 tires, the lock-up, and now 4.0 head and EFI, I can hit 70 at around 2500rpm. With the Carter and non-lockup, I was very close to 3000rpm.

[standup650]

I have the 3.55 axles on my Wagon, with 258, 3spd. auto TF998.  I swapped in a TF998 with lock-up because it scared me soo much down the highway.  With 235/75 R15 tires, the lock-up, and now 4.0 head and EFI, I can hit 70 at around 2500rpm. With the Carter and non-lockup, I was very close to 3000rpm.

Witch ones are lock up?

[mach1mustang351]

My rig is a 4.0 with an AX15.  The 355 is factory on the cherokees with the same setup.  Should be right... I hope.

[captspillane]

3.55 is perfect for an AX15 or T5.

Actually the standard XJ gear ratios were 3.07 for manual and 3.55 for automatic. With 3.07 at highway speeds you are stuck in an awkward spot where its a little too high for 4th and a little too low for 5th, and you are constantly upshifting or downshifting. Its annoying. With 3.55 gears you won't have that problem and you can still cruise at 85 or 90 mph if you're so inclined.

The overdrive in the XJ's AW4 makes 3.55 perfect for an automatic too, but without an overdrive its too low of a gear. 3.07 works well with the stock TF998 if you drive aggressively and 2.72 is perfect if you want a mixture of performance and fuel economy. Most "towing" package Eagles had 3.07.

[DaemonForce]

With 3.07 at highway speeds you are stuck in an awkward spot where its a little too high for 4th and a little too low for 5th, and you are constantly upshifting or downshifting. Its annoying.

This got my attention. My Eagle has 2.73 gears with an automatic and I'm thinking of doing a T-5 swap after I rebuild the engine to fit my specs. I've thought about dropping the gearing to 3.xx but would I even be able to use 5th gear if I leave the differentials alone? All I ever do is freeway driving on flat pavement.

[BenM]

With 3.07 at highway speeds you are stuck in an awkward spot where its a little too high for 4th and a little too low for 5th, and you are constantly upshifting or downshifting. Its annoying.

This got my attention. My Eagle has 2.73 gears with an automatic and I'm thinking of doing a T-5 swap after I rebuild the engine to fit my specs. I've thought about dropping the gearing to 3.xx but would I even be able to use 5th gear if I leave the differentials alone? All I ever do is freeway driving on flat pavement.

Maaaaaybe, depending on the overdrive gear. It's a 1.96 final ratio at .72 OD and 2.34 at .86 OD 5th gear. If you have the .86 overdrive it's doable.

[captspillane]

My Eagle has 2.73 gears with an automatic and I'm thinking of doing a T-5 swap. Would I even be able to use 5th gear if I leave the differentials alone?

I consider 2500 RPM's to be the minimum RPM needed when the engine is under full load going up a hill or trying to maintain a speed higher than 70 MPH. Sometimes it’s more efficient to coast at a higher gear at idle, but then you would have to downshift to get efficient power from the engine under load. 2500 RPM is then considered the minimum RPM necessary to stay in that gear under load. Likewise it is approximately the RPM you'll have the engine at in the new gear after you've upshifted while accelerating up a hill. Keep in mind that most of us memorize shift points in mph because we don’t have working tachometers.

This table shows shift speeds corresponding to each gear of a T5. A four speed is nearly identical except that it missing the fifth. The table shows that you need to be going at least 64 mph to stay in fifth with 3.54 gears. It says you need to be going at least 74 mph to consistently stay in fifth with 3.07 gears. That works pretty well but it plagues the trip with many more annoying downshifts to fourth along the highway. It says that you need to be going at least 97 mph to shift into fifth with 2.35 gears. Good f rickin lord. That's outrageous. It also says that first gear with 2.35 gears is almost exactly like starting in second with 3.54 gears.

You can drive the car just fine with 2.72 gears but its harder to drive because its more likely to stall. The last person who drove my 2.35 T5 SX4 was left in tears because they couldn't stop stalling. That same person drove my other vehicles without a problem. The shifts have to be much longer and put more wear on the clutch. You will not use 5th gear except to coast downhill. If you  look at the chart it says you'll be at 83 mph at 2500 RPM in 5th. That is not a high enough RPM to produce enough power to keep an Eagle rolling on level ground at that speed.



The minimum speed per gear in mph while at 2500 RPM with a CJ T5 (4.03 first/ 0.86 fifth) and 205/75R15 tires:

Gear- 3.54- 3.07- 2.72- 2.35
1- 13.66- 15.80- 17.83- 20.64
2- 23.23- 26.86- 30.32- 35.09
3- 36.70- 42.44- 47.90- 55.44
4- 55.05- 63.66- 71.85- 83.17
5- 64.02- 74.02- 83.55- 96.70

[carguy87]

When you are saying that 2500 rpm is minimum to produce enough power to maintain gear. Are you assuming stock 4.2L?  I assume with upgrades that the rpm could be reduced, take my setup for instance; 4.2L block .030" over, 4.0L head milled ported and polished, MPI, and 60KV ignition coil running on 30lb/hr. injectors.  I believe I could drop that number safely to 1800rpm.  I pulled a 9ft. U-haul trailer loaded up with my most precious 6ft. long tool box fully loaded(probably tipping the payload capacity) but I was still able to cruise at a comfortable 2200 rpm up and down hill on the expressway.  Just a curiosity, would the weight difference in a SX/4 and Wagon be enough to change that number as well?