Very, very hot xfer case?

[griswald]

Hello all,
As you may (or may not) have been following my troubles with a 1971 IIA 88, I wanted to give an update and ask a question.

There seems to be a binding under load and "juddering" going thru 2nd, 3rd and sometimes 4th gear.Typically only under load or going up hill. You can "power" thru it, and at about 3250 or more RPMS it seems to dissapate.

I have replaced: Plugs, wires, coil, points, condensor, dist. cap and adjusted valves.

The shaking seems to start only when the vehicle is warmed up. There seems to be a driveline shudder, but you can power through it. I have also replaced u joints in the rear prop shaft and there seems to be no play in the slip joint.

Front drive train does not seem to have issues at all (all tight, and good)

My diffs front/rear do not whine. The truck has a rover drive and it does not howl... there is good compression in all cyls and I have changed the xfer and rover drive fluids (looked good) main box topped off too.

SO...I just went on about a 6 mile drive going up to 55mph...truck good and warm. Got home, felt diffs (warm) gear box (warm) Xfer box extremely hot, to the point it will burn your fingers if you leave them there more than a second or two. Same with Rover drive, scalding hot...

Is this normal? I mean guys (and girls) this thing is hot like an exhaust manifold

What could be going on? (Binding of some sort?) there are NO noises at all coming from any of this and the e brake drum is also not on or locked up...

Rear wheels will turn easily when truck is jacked up

Your best guesses would be appreciated!

Best,
Griswald

[Mercedesrover]

The Roverdrive runs VERY, VERY hot. Use synthetic oil and run Ray's heat dissipating transfer case cover.

[Tim Smith]

I've got a roverdrive too but I've never seen the transfer case get scalding hot. Of course I haven't been checking either so who knows. This sounds like a lubrication problem to me. Jim suggestion above is probably the same route I'd go too.

[griswald]

Mercedes, Tim,

Thank you both for the suggestions, I will try them! Any ideas about what could lug/shudder/judder only under load (acceleration) or on a hill?

Could a bad driveline do this? If the splines are worn or if it is out of balance? (Leaning to this now as at HIGH speed) when coasting, their is a noticable vibration around 60 when coasting down the road...

Best,
Griswald

[Tim Smith]

I've noticed juddering when the ebrake is sticking but you say that is cool to the touch so I'm not sure about that.

The vibration at speed sounds familiar too. I once had taken my rear drive shaft out for a clean up and inspection. When I put it back together I failed to align the balance marks in the shaft correctly and had a very weird harmonic balance type shudder but only on overrun. Under power it didn't seem to make any noticeable effect.

I'd take a good look at the U-joints and also check and recheck the connection of the drive shafts on both ends. If you have locking hubs, then unlock them for a drive and then lock them for another drive to see if you can't eliminate the front prop shaft. If you don't have locking hubs then pull the front prop shaft and test it. You could also do this with the rear prop (and in 4x4 and locked hubs ;)) to eliminate that.

Be sure to block the wheels while you are pulling shafts so it doesn't end up rolling over you unexpectedly. :eek:

[Sputnicker]

Vibrations at certain speeds are often related to wheel imbalance or a tire starting to separate internally.

[robert wood]

We make the Roverdrives here and I have been taking advantage of the current hot spell in BC to measure Roverdrive and transfer case temperatures. Method is go like hell in 88 for twenty miles on new Sea to Sky highway and take readings with an infra red thermometer. Understandably a brand new overdrive gets hotter than a run in one. The hottest area in the whole assembly is the lower part of the transfer case. Top reading measured is 145F with the finned transfer case cover. I used to see higher temperatures without the cover especially using cheap high sulpher oils which is why we now suggest synthetic.

I also have a rumble at certain speeds and think it may be a unbalanced prop shaft agravated by the higher lift of Parabolic springs. I'm changing it out over the weekend and will advise if it improves the situation.

Ray

You might w

[Tim Smith]

Hi Robert,
Welcome to the forum.

I have to say that the Roverdrive does get hot. Not scalding as above but very hot would be a good identifier. Very hot.

I do not in any way call the Roverdrive into question. It has served me well and the previous owner too. After a hard on the peddle run for a few hundred miles it does get hot. Very hot.

Case in point, my first run with this truck was a 1300 mile jaunt from FL to CT. And yes I pushed the truck hard. In NJ on a really hard try I buried the speedo at over 90 unadjusted for the 33" tires. Probably over 100 actual MPH at that point but there you have it.

The Roverdrive took it. But I must say, the whole after-trans assembly was smoldering the stink off of oil. Your Roverdrive gets hot but not unless it's needed. Still a very very good peice to kit.

To the original poster, there is something wrong. Try identifying the heat by feel to the area. Or try changing oils like Jim said. Not sure...