When do you replace the rear driveshaft?

[ericw.]

In case it's relevant, my question is in the context of a 2023 JT Rubicon Diesel.

I have a long list of mods to be installed which includes a 3.5" MetalCloak lift and 38"x13.5R17 tires.

One of the shops that I've been talking to is recommending that I go ahead and do the rear driveshaft (already doing front)... but I'm wondering when that is actually necessary? Is this a weak point that I should be worried about with 38's and a 3.5" lift?

I never see anyone really talk about replacing the rear driveshaft, or what stage of a build is that recommended/required.

Thanks in advance! And hopefully this thread is in the right forum section.

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[fourfa]

Your shop wants to bill some extra work, I’d guess. What was their reasoning for replacing working parts?

 

[Coltron_Actual]

It's a metal tube. It doesn't just go bad lol. But things might wear out sooner.
At best, maybe some fresh U-joints. I'd ask them for reasons why, and see if smoke is being blown up your back end.

 

[ericw.]

Your shop wants to bill some extra work, I’d guess. What was their reasoning for replacing working parts?

It's a metal tube. It doesn't just go bad lol. But things might wear out sooner.
At best, maybe some fresh U-joints. I'd ask them for reasons why, and see if smoke is being blown up your back end.

We're not repairing anything.

The reason behind the suggestion is just because we're installing a ton of upgrades to outfit the vehicle to be capable off road. I wouldn't assume any malice in the suggestion.

I'm just curious, at what point in a build does the rear driveshaft become a weak point? Because I haven't heard of people replacing them in the JT very often.

 

[Camaroboi13]

For reference, I’m at 4.5” of lift with both front and rear stock driveshafts. I have a carrier bearing spacer, and I do not disconnect. When it breaks, I’ll put another stock one on it.

 

[fourfa]

Agreed it’s not a common weak point on the JT, and seems to handle large articulation without problems

I blew one up on a Tacoma, dented it on rocks and then it torqued in half like a pretzel. Current stock JT shaft has taken much worse. The ribbing on the torque tube adds a lot of strength.

 

[Janster]

We're not repairing anything.

The reason behind the suggestion is just because we're installing a ton of upgrades to outfit the vehicle to be capable off road. I wouldn't assume any malice in the suggestion.

I'm just curious, at what point in a build does the rear driveshaft become a weak point? Because I haven't heard of people replacing them in the JT very often.

For what this is worth…. Because I have no JT driveshaft experience…. We had a built YJ that we upgraded to a Tom Woods drive shaft. The stock YJ driveshaft is as short as your forearm and you need a longer shaft when you lift 4.5”
We had to upgrade…..and upgraded the ujoints.

Again… 2 cents worth here….. As long as you can keep the driveshaft off the rocks …. The U-joints tend to be the weak point. If the driveshaft is hollow and you tap it on the rocks too hard, they can/will curl like a pretzel. If you break a U-joint - hopefully you catch it soon enough before it destroys the ears. Once you destroy the ears…well, now you’re talking a new driveshaft.

My 2 cents … Run with the JT OEM driveshaft. Carry some spare u-joints. If you manage to destroy the OEM driveshaft….. then, it’ll be time to upgrade.

 

[davesparky6]

Unless there’s an excess angle or excess torque / power issue, I’d go with the hindsight precaution as follows:
If you see the drive shaft behind you in the rear view mirror, it’s probably time to replace it.

 

[Rusty PW]

I have a 4" lift with the stock rear driveshaft and a 3/4" Rock Jock spacer. Have about 20,000 miles with no issues. I've wheeled at Rausch Creek and Moab with the set up.

 

[ericw.]

Yeah sounds like it's probably unnecessary unless I just wanted to reinforce for the sake of being over built for 98% of what I do.

Their suggestion likely comes from their perspective, and they regularly rock crawl a lot harder stuff than I usually do.

 

[Stan H]

For what this is worth…. Because I have no JT driveshaft experience…. We had a built YJ that we upgraded to a Tom Woods drive shaft. The stock YJ driveshaft is as short as your forearm and you need a longer shaft when you lift 4.5”
We had to upgrade…..and upgraded the ujoints.

Again… 2 cents worth here….. As long as you can keep the driveshaft off the rocks …. The U-joints tend to be the weak point. If the driveshaft is hollow and you tap it on the rocks too hard, they can/will curl like a pretzel. If you break a U-joint - hopefully you catch it soon enough before it destroys the ears. Once you destroy the ears…well, now you’re talking a new driveshaft.

My 2 cents … Run with the JT OEM driveshaft. Carry some spare u-joints. If you manage to destroy the OEM driveshaft….. then, it’ll be time to upgrade.

I ruined the ears on a Ford Driveshaft . Took it to a local driveshaft shop and they re-tubed it and put a bigger yoke in it and used a u-joint that was bigger on one side then smaller to the yoke and man was it strong . Driveshaft shops can do lots of stuff.

 

[3VOLVE]

Like @Rusty PW, I’ve had a 36k on stock rear driveshaft, with a Teraflex spacer, and wheeled heavily on 37’s with no problems. The axle was replaced only after ripping the rubber/plastic off the stock unit.

 

[ericw.]

Is it normal to need a spacer with just a 3.5" lift and the 2 piece driveshaft? I'd probably just invest in a 1350 driveshaft before spacers.

 

[3VOLVE]

Is it normal to need a spacer with just a 3.5" lift and the 2 piece driveshaft? I'd probably just invest in a 1350 driveshaft before spacers.

Carrier bearing spacers drop the driveshaft to bring it into proper alignment and is a cheap alternative to the 1350.

I didn’t upgrade my rear driveshaft on my current JTRD on 40s for 18k until I re-geared. I have had no problems with the OEM rear driveshaft to date.

 

[Splenda]

Is it normal to need a spacer with just a 3.5" lift and the 2 piece driveshaft? I'd probably just invest in a 1350 driveshaft before spacers.

I installed a carrier bearing spacer with a 3.5" lift.

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