tokelyn

88 xj 4.0 BA10/5 NP231 HP D30 D35
RC 3" lift 33" tires
When I put it in 4wheel high and push on the gas it makes a "popping" noise When I just cost there's no noise When I put it in 4wheel low there's no noise again What could be going on please help???? I'm new to this....

rompnXJ

your transfer case chain has probably stretched and is slipping on the sprockets. Happened to me, and happens to others pretty often.

remove the rear cover of the tcase and have a look, post a pic if unsure.

** before you do that, take a sharpie or a crayon and make a line down your front driveshaft (across the yoke), then hop in your jeep and duplicate the sound again, then recheck your marks. this will tell you if your front d/s slipyoke is slipping. And while you're under there, give your front pinion a wiggle to see how much play is there; if the pinion bearings develop too much play, the pinion gear will slip on the ring gear.

tokelyn

Ok how hard is it to put a new chain in
I've been a mechanic for 3 years now so I can do this just want an idea how hard

rompnXJ

Easy & straightforward, a little time consuming. the chain can be replaced without pulling the case off the jeep.. However I deff recommend pulling the case off and doing a full rebuild along with the chain. The bearing for the front d/s output shaft (one of the sprockets are attached to that shaft) develops a lot of play with frequent 4wd use, excessive play in that bearing can cause the chain to slip on the sprockets.

rebuild kits are tyically 100-150 for all the seals & bearings, replacement chains are like 60-70 bucks.

If you got the coin, you can upgrade your 1" chain to a 1.25" by swapping in a widechain kit from JB conversions (or other people, idk who all makes em). the kit includes the wide chain and wider sprockets.. also you could pull the wider chain and sprockets from a 231 from a chevy s10/blazer from a junkyard or something.

Check all the basics before tearing into your transfer case.

tokelyn

So around 210 to rebuild and 125 with a 35 dollar core from the local junk yard
Last time I went out there were so any xj I'm sure at least one has a 231 tcase
I'm going to look Tuesday and then save some money to swap a tcase I think
How am I sure that it's the tcase tho
What about u joints and I have a cv axle on my driver side could that be it?
Just want to make sure I buy the right part to fix it you know what I mean

kgm

I would replace the u joints in the front drive shaft before rebuilding the transfer case, unless you know when they were replaced. May still be the t-case but u joints are cheap and easy.

hankthetank

CAD shift fork worn not engaging shift collar in front axles properly?

Turbo X_J

Could be the mounts, is anything hitting the exhaust?

tokelyn

no idea when replaced so I'll try that first

tokelyn

My fork was broke I replaced that and it's still doing it

tokelyn

My exhaust was hitting the axle so I cut it Down it hits my rear sway bar bt the popping jerks the hole jeep so I know it's not that

hankthetank

the fork may not be pushing the collar over all the way. the diaphragm in the CAD could be ripped or torn not letting the vacuum hold the fork over all the way. this happened to me. I broke two forks before I decided to permanently move it over in the housing. now it doesn't pop out.

tokelyn

I plan on converting to a one piece axle I have a HP D30 up front with the cad so I want to go to junk yard and I got the block off plate form a guy on here just need money

tokelyn

40 buck for all u joints up front just wantin to see my pay check tomarrow
If I fix all u joints and it's still pops what would it be the tcase Chain??

Turbo X_J

I don't see the axle shaft u-joints as being your problem unless you get a lot of "feedback" through the steering wheel when making turns. Easy enough to check the chain with the T/C shift it into 4 disconnect the driveshafts, rotate the shafts one CW one CCW then the opposite direction by hand. If there is a ton of slop you'll feel it.
ETA:
The fact it only does it in 4h and not 4L probably points to an internal issue in the T/C.