The ongoing saga continues. While I continue the search for the rumble, grumble, vibration up cause the truck had developed a loud squeal that seems to go away when I step on the break ? Any thoughts? 94/80.
Loud squeal from under the truck?
- Thread starter joey.w
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Could it be the brake wear indicators? It seems like they would continue to squeal when the brakes were applied though.
Front axle related?
- Thread starter
- #4
Ok I think I found the cause of the rumble and heavy acceleration vibration :- The universal joint right off the transmission to the front driveshaft is loose movable back-and-forth by hand ! Guess it's time to replace that. I have no clue whether or not that will get rid of the squeal - i'll post something up as soon as I figure it out . thanks for the replies !
Jack up each end of the front axle so the tire is 1/2" or so off the ground. Then grab the wheel and shake it like a gorilla, up-down, left-right. You are looking for any play. Your wheel bearings may be toast.
- Thread starter
- #6
ok next question.... with the front driveshaft off is the truck drivable temporarily ? my guess is no seeing that there is a loud clicking noise when putting it into park and in "park"
the truck still rolls.
the truck still rolls.
Yes it is drivable. IF you have a Center Diff Lock switch. I believe the 94 doesn't come with this so you would have to have done the 7 pin mod and CDL switch. I think there is another way to lock the Center diff without it. Search here on mud and see. If you have the CDL switch just push the button and drive it in rear wheel drive.
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- #8
Thanks -yes. I have the CDL switch and the 7pin mod was done before I bought the truck . I just need to drive around and get parts so I'll give it ago thanks for all your info this was really helpful !!!
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To drive with one shaft and no CDL switch: With the key to run and/or the engine running, shift low range, should get the CDL and ABS lights, remove the Diff fuse from the box by your left knee, then shift high range and drive. When the shaft is reinstalled, simply replace the fuse, the CDL will unlock.
The UJ's often squeal when they are starting to seize. Also, careful when driving with RWD only, When pootling about you will not notice the difference, pushing hard on corners and you will find the car running wide i.e. under steering.
regards
Dave
regards
Dave
And braking seemed to be different as well. Like the front wheels locked up right away while the rear wheels were slower to engage.
- Thread starter
- #12
Yes! The truck drives like a Gokart when only in rear wheel drive! I seriously have to watch my cornering. One more question that LS1fj40 already answered. I have to order new universal joints which will probably take about five days to get here.... As I said above my truck has the CDL 7 pin mod. Is it OK to drive this thing around for a few days like this even on the highway Or do I risk damaging something? The truck seems to drive pretty great when in rear wheel only.
Dare I say my 80 drives BETTER in rear wheel drive. I'm seriously considering going part time because I like how it drives better. I drove mine 2hrs on the highway (cue 3FE jokes about that only be 15 miles...) the day after removing the front drive shaft. Road like a dream.
I just installed my front driveshaft and removed my rear driveshaft in order to replace the U Joints on the rear. Holy cow it rides smooth. I can't wait to get the rears put in to see what it's like.
This is always a difficult subject to debate and is very subjective, because everyone has a different requirement from their vehicles allied to a different driving style. Stating your car 'drives better' tells me (and everyone else) nothing. There would have been the 'perception' it was better as you had less vibes/noises from the shaft you removed but, was the road holding better? Was traction pulling away improved? Was the vehicle more stable during overtaking manoeuvres and so forth.
The very fact that 4WD is proven to aid traction during cornering pretty much says it all but, lets look at it from a layman's point of view.
Remembering that the inertia of a couple of tons wants to go in one direction only, straight on. You want to change that direction by turning the steering wheel, the moment your steering wheels are not pointing in the same direction as the rear (driving) wheels you are generating scrub or resistance to that turn input you have requested, any amount of scrub is the very beginning of the loss of traction. So what if your tyres were being driven in the direction you want to turn them? It can only result in less scrub although there is a caveat at work here. The action of having a differential in the system (whether driven or not) in itself increases drag across the axles, but obviously not as much if the two wheels across an axle were locked but, definitely more than the two wheels freewheeling on the same axle, there is also the drag factor when in 4WD from the CD.
So having the front wheels 'pull' the car around the corner 'scrub' and hence traction loss is reduced, IMO and IME 4WD is the better deal for the 80. Now there is a clue there right...'the 80'. If I wanted to go quicker around the corner and there was space available then rear wheel drive 'drifting' your BMW would certainly be a contender for getting around the corner quicker than the 80, so it is horses for courses, just remember you cannot overturn the laws of gravity.
I noticed the loss of directional 'response' when driving in RWD only, this showed up only as under steer as I was pushing into a bend. Until that point there was no other changes in the vehicles road holding or manners. Now I did not change my (39 years) driving style overnight, the car was simply responding differently to a change in the transmission and sharing of power, I fitted the front shaft and the vehicle returned to it's normal quite neutral (for it's size) cornering behaviour.
regards
Dave
It felt more responsive and smoother. Not just because the clunk of the U Joint wasn't there. It also felt more powerful. This could just be perception but the seat of the pants feel was different. I don't know if splitting the hp between the front and rear makes a difference or not. I'm not an engineer, just going by what I "felt".
I know I've read arguments in favor of part-time because of less wear on the front axle. If this is the case then it would make sense that there is more horsepower going to driving the rear wheels and it isn't being robbed by the front axle. Once again, I don't know, just how it "felt".
There is a 3FE joke in there somewhere.
I'm sure there is. Just don't blow a head gasket thinking about it too hard...