Popping on acceleration

[ahkistler]

Hey all,

I'm in the process of resurrecting a 1997 AWD Explorer. It's been a tricky endeavor thus far. I'm now stuck on trying to figure out a popping on acceleration.

The work I've done so far includes:
1. replaced CV axle (driver's side I think, it's been a while)
2. replaced viscous coupler/rebuilt transfer case (used to have an ungodly loud popping noise on turns - fixed!)
3. Swapped Front drive shaft with one from a they-pull-it car yard (Are there different lengths of drive shafts within a cm of each other? because the original removed very easily the replacement I had to loosen the front differential mounts to get the driveshaft to fit)
4. Opened and inspected front differential, everything looked fine so resealed it.
5. New radiator (There was transmission fluid in the radiator, and water in the transmission, transmission was flushed/new filter put in as well as drain nut; trying to flush all the water out)


Summary: Used to pop on turns, no popping on acceleration. After rebuilding transfer case and reinstalling, all popping was gone. Replaced radiator and dropped the pan (may have removed front driveshaft) and once everything was back together, it started popping on acceleration. If I very gently accelerate, it doesn't pop, if I give it more than ~20% throttle, it kind of clunk/pops until over 25mph.

I'm wondering if removing and reinstalling the differential mounts might have something to do with it?

 

[DUNE RCR]

Have you checked your ball joints? I had a similar issue with my 99 X and found the popping/clunking to be the lower ball joints. This was after replacing both cv's, upper control arms on both sides, new wheel bearings both sides, and rebuilding the diff.

Hope you can figure it out cause I know how annoying it is for random noises that dont belong.

 

[ahkistler]

Forgot, I also replaced the driver's side lower ball joint. Glanced at them both anyway, looked ok, I'll look again in the morning.

Edit: Would a ball joint only pop on acceleration?

 

[Turdle]

yes, early 97v8 has it's own front drive shaft-for late 97-98 and up there are 2 possibilities. You need to measure between the welds on your original one.

 

[ahkistler]

yes, early 97v8 has it's own front drive shaft-for late 97-98 and up there are 2 possibilities. You need to measure between the welds on your original one.

Well, balls (pardon my french). I gave the original driveshaft to the place for core charge, and this was prob 6 months ago.

 

[Turdle]

ok, measure the one you have--please
Measure between the welds, from the center of the bead to center of bead


I think you have one which is 23 3/4" but you need 22 7/8 "

 

[ahkistler]

It's out at my house, which doesn't have internet. I'll measure it and post tomorrow. Also, I'd think it's the other way around, the replacement shaft seems too long, not too short.

Completely unrelated question, I was just talking to my brother, spit-balling what it might be. He says that the transmission filter has a bolt or nut holding it in place (He's got a 97 4wd v6 this one's a 97 v8 awd) there wasn't a a nut holding it in when I pulled it out. Puttin the new one in, it felt like it was going to fall out but I thought that was just the way it was. Could the filter be banging around and screwing with the transmission?

 

[Turdle]

v6 or v8? if v6 disregard my posts. v6 are 4wd, v8 are awd

is there a 4wd selector switch on the radio bezel?

 

[ahkistler]

V8, mistyped it, corrected previous post.

 

[ahkistler]

Measured the shaft at 23 3/4.

You're right, I think the replacement shaft is too long, I misread your post. [as 23 3/4 vs 23 7/8].

Gonna swap out the filter again, and look for a new shaft.

 

[ahkistler]

Put the filter back in, pulled the front drive shaft out of my brother's '01 awd, which was the correct length, no change in popping.

Two thoughts:
First, the cv cup of the drive shaft seemed extremely loose, and sounded like it was allowing air to come in and out. Is it supposed to do this or is there a rip? (I couldn't see one, and this is not a known good part, there's a ton of noise with the '01, which I think is the diff, but maybe was partially the shaft)

Second, I've tried flushing the radiator and the transmission a couple times, but the fluid seems to stay the same milky red color. Could this be the transmission stuttering under load?

The radiator is new, but I reused all the lines, maybe the input output lines from the tranny on the radiator aren't making a good seal? Are there any methods to do a complete fluid flush in the coolant system?

 

[ahkistler]

Any thoughts?

 

[ahkistler]

Coolant system has been flushed.

Popping goes away when the front driveshaft is out, anybody have any common culprits?

 

[ahkistler]

Rebuilt the transfer case again. The popping is completely gone on turns, but it sounds like there are gears slipping on hard acceleration. Just replaced the wheel hub, thinking of replacing the driver cv axle again.

Thoughts?