Question for you 4x4 RAM guys

[Dr. Righteous]

OK,
Got a '85 Ramcharger SE 4x4.
When you accelerate from a stop I sometimes get a loud BANG
and sometimes a physical jolt when it happens.
I took it to a driveline shop expecting to be told it was the slip yoke (I have already replaced the U joints) He told me it was most likely the chain in the transfer case was worn out and slipping.
That floored me! Is it true that while you are in 2WD that the CHAIN in the xfer case is DRIVING THE REAR WHEELS????
I thought it was disengaged when you were not in 4x4.

(BTW, he slid under the truck and checked the driveline and slip yoke. He said they were in good shape)

If I do need to get the xfer case rebuilt, what does it usually cost??
OUCH! Didn't count on this!

[ehostler]

Power is always routed through the components of the transfer case. The transfer case is always turning both driveshafts (which is why you lock and unlock the front hubs). So it is very possible that you could be having problems in the transfer case.

[Dr. Righteous]

Well, I expected as much in a full time 4x4 truck. But I have had all four wheels of the ground on jack stands when I was trying to figure out a noise problem before. With 4x4 disengaged the front drive shaft does not turn . This truck has center axle disconnect (CAD) and disengaged the front wheels don't turn the driveshaft either.

The few times I have been off road it performed flawlessly.
Never figured the problem might be the xfer case.

Well, I am new to 4x4 and I am learning the hard way it seems

[goose]

The main shaft inside your case has front and rear outputs and is driven by a chain off the input shaft (from the transmission). The chain is operating all the time, and hence so is the rear output shaft (which is always locked to the main shaft). The selector lever in the cab tells the main shaft whether to mesh with the front output shaft or not. Different transfer cases operate in varying ways but that is the typical setup in a part-time 4wd rig. Full-time 4wd is a different ball of wax, there are lots of variations and I don't know them all. Also I am not completely clear on how the high/low gears are selected inside the case. A trip to the local library/magazine stand should result in lots of magazine articles on transfer cases and hopefully yours will be featured (you know what kind of case you have right?) I think you may have an NP205 but don't quote me on that. The 205 is a good case and will stand up to a fair amount of abuse. The other really good case is the NP203, which is the same basic unit except it is gear-driven instead of chain-driven and is part-time instead of full-time. You can convert your full-time to part-time for about $100 with a Mile Marker kit (in Summit catalog).

[ehostler]

It would appear that I was mistaken of the operation of your transfer case. goose seems to have a much better grasp on this, than I do.

[Brian Mills]

O.K. Doc, you have a 208 T case, and the chain thing is B.S.

The varmints name is AXLE WRAP.

When you stop, the last little bit you move before the stop, the brakes lock and the wheels still roll forward a hair, the diff rotates down, as in pinion looks at the pavement instead of the trans. You hit the gas, the diff rotates up...bang, you hit the gas alot, you feel it.

Those 3" blocks between the spring and diff give the leverage that makes this happen. I put Rancho Kicker shocks on my 91, and it went away for a year, then I changed the crappy 1000 shocks out for 5000 shocks and I haven't felt it or heard it in 3 years.

On my 85 RC I put a Skyjacker 21/2" suspension complete with all 4 new springs. The rears do away with the blocks, and it went away. I can still make it happen if I root on it hard.

That's all I can say from this distance and not driving it. Hope this helps.

[Dr. Righteous]

My understanding of how a xfer case worked didn't jive with what the guy at the driveline shop told me.
Having the chain in motion while you are driving in 2wd is one thing. But the power for the rear wheels being transmitted through the chain is completely another! If that was the case chain failures would be a plague!
I know too many guys that have never had a xfer case problem, so it didn't jive.

Now, a fix for the axle wrap problem. I replaced the rear shock with the factory size gas shocks. Now that I think about it the problem was much worse before I replaced the shocks. It banged on me just about every time I stopped. Now it only does it when I put my foot in it a bit agressively.
Also, tall off road tires would tend to make the problem worse I guess. My RC has 31" ATs.

OK. Sounds good.

[Brian Mills]

That's right, you got the picture.

[Brian Mills]

By the way, you might want to take a look at a Rancho catalog and see the Kicker Shocks, they don't replace the existing shocks, they are a whole new shock system that tie the spring to the frame. You keep the regular shocks as well. Just wanted to be clear on these.

[ROCKHOPPER]

I don't want to counter the advice that Brian gave you but replacing you shock's is not the way to take care of axle wrap, I have a Warn Black Diamond 4" Lift, this kit come's with 4" blocks for the rear, as you know the Ramcharger already has block's in the rear, so I now have 7" of block in the rear, and you can check out my web page to see how I am with my truck I will link it below, what you need to do is work on a combanation of shock's and your spring's, as the springs get old the get weak alowing your axle to turn, they make a shock that goes over the top of your spings to help stop this but fix it the right way and have your springs replaced, this is just a sugestion but I hate to see you through money at a temp fix. later IM OUT>?RH

Rockhoppers Home Page

[stick4406]

Did you pay close attention to the transmission mount biscuits that sandwich the rear crossmember-usually they get very oil soaked and squishy-My old one (84 w/4") did this also.You might just want to take an impact gun and double check u-bolts and rear spring bolts.As for the chain idea,that is b.s..The chain is static when not engaged.The only time you'll hear any thing from it is when 4 is locked in and there is alot of loading and unloading on the driveline(read bouncing around a mud hole in 4wd)-just my 2 cents............. stick