Front wheels lose power under load

[Isan]

Short story: My front tires were not spinning in 4low, and a loud clunk sound happens if I push it too hard. Similar effect in Part Time.

Long story: Took the Jeep out on a decent trail for the first time in a while, hit an obstacle where I couldn't go further. I needed my front wheels to spin, and they werent. I was in 4 low, giving it decent fuel and was unable to move. I had a spotter confirm my front tires were not spinning, and there was a loud clunking if I gave it too much fuel. Shifted in to 4 PartTime, which got me over that obstacle, only to have a different one have a similar effect. I had someone look under my car and they said that the front driveshaft was also not spinning, however when that loud "clunk" was heard again, they said the driveshaft spun for a second before stopping again. However, as long as im not stuck, that is, if im just going up a sandy hill, all 4 tires will spin, they only have issue under heavy load. I have a 2006 with a selec trac transfer case.

TL;DR: Front driveshaft doesnt spin in 4wd while under heavy load. Loud clunk sound. Selec Trac. Please help

 

[24turbo]

my guess would be the chain in your transfer case is loose and when you load it heavily, it "skips" on the gears.

Not easy to confirm without taking the transfer case apart, but all the symptoms line up well.

 

[Isan]

my guess would be the chain in your transfer case is loose and when you load it heavily, it "skips" on the gears.

Not easy to confirm without taking the transfer case apart, but all the symptoms line up well.

yea i was thinking that too, probably just going to replace the transfer case with one at a salvage yard. Its $90, which is way cheaper than any rebuild or new one, and worst case i pull a dud and Im out $90

 

[mercdudecbr600]

Not a real hard job but easier with 2 folks and still takes a few hours. Having just done this job, I’d punt and get a bulldog rebuilt unit with 18mo warranty. IMO it’s not worth the effort to install a used unit when a new one is a few bucks more.

 

[Isan]

Not a real hard job but easier with 2 folks and still takes a few hours. Having just done this job, I’d punt and get a bulldog rebuilt unit with 18mo warranty. IMO it’s not worth the effort to install a used unit when a new one is a few bucks more.

Where are you finding a rebuilt unit for "a few bucks more"?

 

[mercdudecbr600]

check ebay

 

[mercdudecbr600]

Pardon Our Interruption...

 

[Isan]

Pardon Our Interruption...

yea so that is not a "few bucks more" lmao

 

[Shankster]

yea so that is not a "few bucks more" lmao

I guess a mid cost alternative would be to buy the salvage yard transfer case and rebuild it. I think you have the NP242 transfer case? - Rock Auto has a rebuild kit for $148.

More Information for USA STANDARD GEAR ZTBK242C

I've never rebuilt one but I think they're fairly simple so it could be a fun little project.

The slipping chain theory sounds very plausible and most likely is your issue, but I wonder if it could be something simpler like it's not fully engaging 4LO? Might be worth checking the bushing on the transfer case lever - if it's broken or missing you might only be going part way into 4LO. I'm just spitballing but I think it's at least worth crawling under your vehicle to verify the bushing is good and the lever is moving through its full range.

 

[mercdudecbr600]

yea so that is not a "few bucks more" lmao

All relative

 

[Isan]

I guess a mid cost alternative would be to buy the salvage yard transfer case and rebuild it. I think you have the NP242 transfer case? - Rock Auto has a rebuild kit for $148.

More Information for USA STANDARD GEAR ZTBK242C

I've never rebuilt one but I think they're fairly simple so it could be a fun little project.

The slipping chain theory sounds very plausible and most likely is your issue, but I wonder if it could be something simpler like it's not fully engaging 4LO? Might be worth checking the bushing on the transfer case lever - if it's broken or missing you might only be going part way into 4LO. I'm just spitballing but I think it's at least worth crawling under your vehicle to verify the bushing is good and the lever is moving through its full range.

Ended up replacing it with a junkyard one, took a few hours, haven't gotten the chance to test it yet. I did end up opening my old one, saw no indication that the chain had slipped, but the output shaft for the front seemed to have some warped and rough teeth on it.

The output shaft is weird. Its got a gear on it for the chain, but the gear and output shaft arent one solid piece. The output shaft has teeth on it, and the inside of the gear also has teeth, and they slide over each other to turn the gear and the output shaft into a "solid piece". Those are the teeth that were messed up, everything else in the case looked fine.

 

[24turbo]

interesting that the spline failed, and not the chain. Guess the weak link is that point.