Topic: drivetrain problem

[Eucalypta]

Hello guys,

Last weekend we went wheeling in the Bulge in Belgium.
On the way back home to The Netherlands, something in my drivetrain broke down:

I was driving aprox 45-50 mph on the highway and suddenly loud bangs under the car what sounded as the exhaust manifold broke of or very loud backfires.
I immediately unclutched and pulled over to the side of the road.
When I unclutch, the jeep rolls freely, however when I put it in first gear and try to pull up: it seems like something is blocking the car. If I'd still pull up, something in the drivetrain gives a loud bang and the car can roll a bit further.

Because it is only when put in gear (any gear), I suspect the transfer case or differentials.
Both are originals and never been overhault since my YJ saw daylight (only got serviced).

Tomorrow the towingcompany will drop of my car and I can open the diff and go on searching from there.

Some (maybe premature) questions for you:
-anyone have any idea what this might be - It might help me start the search and then I know what to look for
-If it is the ring/pinion - I now have 4:10 - I might like to regear. I heard 4:88 is the highest you can go in a standard D35 axle?
-If it is the transmission case: would it be wise to upgrade to a higher turndown ratio ??

Well, a lot of "if's": hope I can fix it fast without hurting my bankaccount to much.

[sharpxmen]

 - same thing happened to me and it was the ring and pinion in the rear axle but it could alos be gears in your transmission
 - yes 4.88 is lowest gearing you can find for D35.
 - I'm not sure what you mean in the 3rd question.

[grumpygy]

Transmission or transfer if it was a differential it would not roll freely in neutral.   Try putting transfer in neutral and trans in gear see what happens.

[sharpxmen]

Transmission or transfer if it was a differential it would not roll freely in neutral.   Try putting transfer in neutral and trans in gear see what happens.

good idea with the t-case in neutral

mine was rolling freely in neutral or clutch pushed but it was the D35 R&P that broke couple of teeth. Gears in the transmission are always meshed so that's the same as the diff regardless if it's in gear or not, same for the t-case (the planetary gears are always engaged even in neutral).

[aw12345]

Take the driveshafts out stick it in gear and see what happens. Everything turns happily look at the rear axle from what you describe the D35 imploded. Most likely culprits the spider gears in the diff. Or ring and pinion.

[Jeffy]

I'm gonna go with R&P.  Sounds like you sheered some teeth off the ring gear.  It's a lot more common then say the transmission and transfer case.  Spider gears or side gears are also fairly common as well.

Once you get it back, put the rear on jack stands and roll it around.  Grab a tire and spin it.  If you're open then you'll need a second hand.  Test it forward and reverse.  Disconnect the driveshaft and spin the axle.

[Eucalypta]

Thnx guys!
I got the car back and put it on stands, disconnected the drive shaft and turned wheels.
Seems like my LS is worn out but that is not the cause of the problem.
Opened the diff anyway, just to see if there is any damage:
Oil slightly metalic but only the "last" "thick" oil that drips out last.
One of the retainers of the LS clutches seems to be somewhat loose but that cannot be the cause of the problem. As I said the LS is worn out so I will replace it when I get the chance.


With driveshaft removed I started the engine.
Uncoupled the clutch and in neutral: no sounds, all seems fine
Coupled in neutral, rattling noice from the transmission
Coupled in 1,2,3,4,5: rattling noise, incleasing in volume at higher gear (5th and reverse loudest)
Transfer in Neutral: same as above.

I guess it it the transmission, maybe inputshaft.

Got a replacement transmission with transfercase and will swap it with my problem drivetrain.
When I have time I can split the transmission and overhaul it so I have a spare.

What are your thoughts?

With upgradint the transfercase and higher turndown ratio I mean to upgrade to a extra low range, for example with Terraflex kit: http://www.teraflex.biz/low-231-hd-transfer-case-21-spline.html

[sharpxmen]

for $2,010 you can get a brand new Atlas with 4.3:1 ratio or 3.8 for $1,940

[aw12345]

I am with Sharp Atlas or Rubicon transfercase. For the Netherlands a Terralo would be a very poor choice. For mud you need wheel speed, a 4:1 doesn't really give you that on top of that you are not supposed to run a Terralo in low range in the top gears, it kills the planetaries. For you proper axle gears might just give you the power needed. For general wheeling the 2.73 transfercase ratio seems to work very well

[N8whitie]

 That same exact thing happened to me last year and I couldn't figure it out. After some investigation I learned that my drivers side motor mount had given out and the engine, tranny and transfer case had all shifted over and my rear drive shaft was beating the hell out of my exhaust. Just a thought for you. Check your motor mounts before cracking your rear diff open like I did.... motor mounts are an easier fix than gears.

[Eucalypta]

That same exact thing happened to me last year and I couldn't figure it out. After some investigation I learned that my drivers side motor mount had given out and the engine, tranny and transfer case had all shifted over and my rear drive shaft was beating the hell out of my exhaust. Just a thought for you. Check your motor mounts before cracking your rear diff open like I did.... motor mounts are an easier fix than gears.

Left motormount was replaced just 2 weeks ago, the right one seems fine, also nothing to see on my driveshaft.
Also, there is a bad rattle in my transmission (see below)

Tonight my buddy and I will swap the transmission and transfer with another one, then we can investigate the transmission.
The diff seems fine.

As for the transfercase upgrade: I'll forget about it for the time being. It was just a though I toyed with. Next time I am going to think about such a thing...I will consider an Atlas.

Thnx guys!

[Eucalypta]

So, swapped the transmission for a AX5 from a XJ.
Just in time for a weekend wheeling at Fursten Forest in Germany. My Wrangler performed great!

The problem is inside my old transmission; you can turn the inputshaft by hand easy, sometimes 10-20 times without any problem but now and then it locks.
Will open it later when I can find the time and see if it is something I can repair so I have a spare AX5.

Because the transfer case is turned about 5 deg down (transmission from XJ) I still have 2 issues:
-It seems the front drive shaft has less travel inwards than with the YJ transmission. Could this cause any problems? Until now it is ok but I can imagine that when it hits the end of the travel the yokes on axle and on transfer case will get hammered severely.
-It is less easy to get the transfer case out of 4Low (shifter gets almost horizontal lined up with the switch on the case). Is there any easy solution for this?

I am happy to be able to wheel again!