Diff Drop; is there a better way?

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Diff Drop; is there a better way?

Postby kperras » Sun Nov 17, 2019 9:53 am

Something struck me today: instead of modifying the front diff plate (cutting and lowering) why not install 1 or 1.5" spacers and longer hardware on the diff plate mounts to lower them? This way you don't have to disassemble anything, just unbolt the plates from the frame, install spacers, replace hardware, and re-install.

Am I missing something?

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Re: Diff Drop; is there a better way?

Postby mudoilngears » Sun Nov 17, 2019 11:03 am

kperras wrote:Something struck me today: instead of modifying the front diff plate (cutting and lowering) why not install 1 or 1.5" spacers and longer hardware on the diff plate mounts to lower them? This way you don't have to disassemble anything, just unbolt the plates from the frame, install spacers, replace hardware, and re-install.

Am I missing something?

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If you use spacers, the bracket contacts the steering components. So unfortunately the modification is pretty much the only way.
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Re: Diff Drop; is there a better way?

Postby robb5 » Sun Nov 17, 2019 12:11 pm

I was looking at cutting the center hole straight down to allow the diff assy to drop out but leave the brackets in place.
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Re: Diff Drop; is there a better way?

Postby kperras » Sun Nov 17, 2019 10:03 pm

mudoilngears wrote:If you use spacers, the bracket contacts the steering components. So unfortunately the modification is pretty much the only way.


I figured it was something simple like this. Thanks for sharing.

I just ordered the last pair of Dobinson's HD Torsion bars on ebay so I'm starring down the barrel of a front end overhaul on my trooper. Steering, suspension, etc. Diff drop makes sense while I'm in there.
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Re: Diff Drop; is there a better way?

Postby robb5 » Mon Nov 18, 2019 9:38 pm

Please share how you tackle the lower control arm bushings.
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Re: Diff Drop; is there a better way?

Postby kperras » Tue Nov 19, 2019 1:22 am

I avoided that job on my last Trooper; might do the same again this time around. I still have the moog bushings BNIB on my parts shelf...
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Re: Diff Drop; is there a better way?

Postby kperras » Tue Apr 06, 2021 1:41 pm

Just following up on this thread.

I managed to make some 15mm / 2/3" spacers for the front diff brackets. This is the maximum you can drop the diff plates, while leaving 5mm clearance to the centerlink and various other parts on the frame. The diff drop bolts are M14x1.5, and I replaced the originals with 90mm length hardware. The stock bolts are 70mm, and slightly long so you could get away with 80mm length.

The install was very easy:
- Support the diff with a jack and jack stands on either side.
- Remove hardware
- Install spacers between the large washers and frame mounts
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- Jack diff back up, not too snug. Leave some wiggle room.
- Get all 4 bolts installed. Torque to spec: 152 N-m / 112lb-ft

There you go..small CV angle reduction without pulling the diff apart. When you have the spacers, this takes 30mins maximum provided your diff plate bolts play nicely.
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Re: Diff Drop; is there a better way?

Postby robb5 » Tue Apr 06, 2021 3:20 pm

Did you do the lower control arm bushings? If so, any tips on the best/easier way to remove them?
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Re: Diff Drop; is there a better way?

Postby Enemigo » Tue Apr 06, 2021 4:41 pm

Could you do this in addition to a diff drop? That'd give you just over 2" of diff drop. Not sure it'd be any more useful at that point though.

Glad you thought outside the box and figured out if this could be done, and exactly how much.
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Re: Diff Drop; is there a better way?

Postby mudoilngears » Tue Apr 06, 2021 4:49 pm

You can’t go too low because the shafts become too “long” and start binding up.
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Re: Diff Drop; is there a better way?

Postby Enemigo » Tue Apr 06, 2021 5:15 pm

You mean on the uptravel? It seems like with the front suspension, all we're really able to do with bolt on solutions is move the center point of the axle anyway.
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Re: Diff Drop; is there a better way?

Postby kperras » Tue Apr 06, 2021 7:03 pm

robb5 wrote:Did you do the lower control arm bushings? If so, any tips on the best/easier way to remove them?


Yep.

I used a hole saw to drill out the center sleeve and rubber, a sawzall to notch the bushing outer sleeve, and a hammer + punch (correct term?) to tap the bushings right out. With the sawzall notch, it's literally light action taps and the bushings fall out.

To press the new bushing back in, I lightly sanded the frame mounts clean and applied a thin coat of grease. The bushings I froze for several days and also applied a light coat of grease. I started each bushing with a couple hits of the hammer, making sure they were reasonably straight, then finished the job with a homemade press made from threaded rod and thick washers.

Nothing too complicated, just lots of elbow grease and time. The holesaw bit and sawzall are both key as they make quick work of each bushing. 5-10minutes per bushing if you go at it slowly, checking to make sure the sawzall doesn't cut past the outer sleeve too far.

Did the entire front end. Took a couple of weeks but that's mostly because I kept ordering more parts from Rock Auto the deeper I went into the Trooper.
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