Axles and gearing - JeepForum.com
 
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post #1 of 8 Old 09-15-2019, 12:50 AM Thread Starter
Marcushall
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Axles and gearing

I have a lifted 95 Grand Cherokee Laredo on 31s, and it doesn’t seem to like 5th gear going down the highway, it’ll shift into fifth while I’m on the gas, but once I let off it drops down to 4th, or at least it feels like it, it has the stock Dana 30 in the front and I can’t find out based on the internet if it has the Dana 35c or the Dana 44, should I change the gearing or what could the problem be..

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post #2 of 8 Old 09-15-2019, 05:53 PM
Some_Anchovies
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The 95 ZJ only came with a 4 speed transmission, 4th being an overdrive gear. The "5th" gear you're feeling is just the torque converter locking up somewhere between 50-55mph, although on 31's this might be higher due to taller tires lowering the engine speed and their extra weight.

In traditional automatic transmissions, the engine spins faster than the transmission due to the torque converter. The engine spins transmission fluid, and this fluid spins the transmission to move the vehicle. There is no mechanical connection between the two, so when you're sitting at a stoplight, the engine can spin while the transmission and wheels are not.

Once you're on the highway at cruising speed and in 4th(overdrive) the torque converter can be locked to physically connect the engine and transmission together, so they spin the same speed.

The torque converter will unlock when you let off the gas, and relock once you're at a steady cruising speed. It won't lock if you're decelerating or accelerating, just when you're cruising at a relatively steady speed and load.

Sounds normal to me but bigger tires mean it might not stay locked as often due to the extra load. You can regear the axles to help. You should have a Dana 30 and 35c. Stock gears are 3.55 and 3.73 w/tow package.

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post #3 of 8 Old 09-16-2019, 08:42 AM Thread Starter
Marcushall
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Originally Posted by Some_Anchovies View Post
The 95 ZJ only came with a 4 speed transmission, 4th being an overdrive gear. The "5th" gear you're feeling is just the torque converter locking up somewhere between 50-55mph, although on 31's this might be higher due to taller tires lowering the engine speed and their extra weight.

In traditional automatic transmissions, the engine spins faster than the transmission due to the torque converter. The engine spins transmission fluid, and this fluid spins the transmission to move the vehicle. There is no mechanical connection between the two, so when you're sitting at a stoplight, the engine can spin while the transmission and wheels are not.

Once you're on the highway at cruising speed and in 4th(overdrive) the torque converter can be locked to physically connect the engine and transmission together, so they spin the same speed.

The torque converter will unlock when you let off the gas, and relock once you're at a steady cruising speed. It won't lock if you're decelerating or accelerating, just when you're cruising at a relatively steady speed and load.

Sounds normal to me but bigger tires mean it might not stay locked as often due to the extra load. You can regear the axles to help. You should have a Dana 30 and 35c. Stock gears are 3.55 and 3.73 w/tow package.

^^^^^ also was wondering someone said u needed to change change my speedometer gear, would that help any before I regear the axles
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post #4 of 8 Old 09-16-2019, 09:12 AM
Timo_90xj
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Quote:
Originally Posted by Marcushall View Post
^^^^^ also was wondering someone said u needed to change change my speedometer gear, would that help any before I regear the axles

Not gonna help at all, speedometer gear is only for the speedometer to show correct speed with taller tires. With the 31s, it's more than likely that your speedometer is actually very accurate right now. You can verify with a GPS- based speedometer - install an app to your mobile phone and check.


31s are ok with the stock gears - not perfect but not horrible either. You will see some gear hunting between 3rd and OD on steeper hills - use OD off- button if that happens - and the torque converter lock-up will kick on and off more often like you are currently experiencing.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


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post #5 of 8 Old 09-16-2019, 08:23 PM
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Is it a 5.2 or a 4.0?

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post #6 of 8 Old 09-17-2019, 11:29 PM
PartyTime
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To ID the rear axle just look at the general shape and bolt pattern and compare to the chart here 🙂 my 95 zj 4.0 has 3.55 gears and I’m on 33s... yeah and it feels sluggish (compared to stock) and with the current wheel size at certain speeds it is in between gears
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post #7 of 8 Old 09-18-2019, 11:19 AM
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Garage
He has a 1995, unless a previous owner swapping something else in he has a D35 regardless of engine.

1994 5.9L ZJ | IRO 5.5" CPLA | NP242 | 33" Cooper Discoverer STT Pro
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post #8 of 8 Old 09-19-2019, 12:45 AM
Kolak
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Is the OP in the USA? Some export 1993-1995 ZJs had an iron Dana 44 in the rear. I think they were all destined for Central or South America. Way back when, Kevin from Kevin's Offroad got hold of some leftover ones so there's still a few floating around here in the USA more than likely. Otherwise all the US models did indeed have the D35 in the rear from 1993-1995.

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