aaronk

Recently it's snowed quite a bit where a live and I was driving with my hubs locked, but in 2WD with an occasional switch into 4WD. When driving with the hubs locked the truck feels even more underpowered and sluggish then it usually is. I can hear a slight hum from the front wheels when going about 50mph as well, but I'm guessing that's just due to everything on my front end now spinning. Should this "drag" feeling be normal? I've read about people accidentally driving with their hubs locked for many miles, but there's no way you could do that in my truck. If you didn't hear the low hum you'd definitely be able to feel that the truck was trying to push itself along with some resistance.

I have not yet checked the fluid in the front diff. When I went to last I was beginning to strip the fill bolt and so I stopped so that I could buy a new one and put the new one on when I got the old one off. I haven't gotten around to doing that yet. Could it be my CV joints? The boots on my CV's are fine, but I don't know about the rest. I just repacked my wheel bearings within the last month. One final note, with the hubs unlocked everything is fine, no drag feeling, no low pitched hum. Any ideas or is all this just normal?! (this is my first 4WD vehicle)

Flash319

My 89 is like that. That is just what you get when you are driving everything through the wheels. That is why ADD was invented. I am surprised that you 94 does not have ADD. The best is to have a ADD front end with manual locking hubs, then you can unlock completely in the summer and have the manuals locked in the winter so all you have to do is pull the shifter but you are not driving the whole front end all the time like you are now.

thook

Hmmmm.....a low hum can be normal, but I can't say I ever feel any drag under the same scenario. That is to say you really shouldn't, and for you to be losing power....well, that's not normal. Check the oil in the diff when you can, then I'd look at cv axles and driveshaft u-joints. Unlock the hubs, jack the truck up and feel for excessive play and/or abnormal noise. Hopefully you still have grease in the cv's and u-joints.

FredTJ

If you can actually feel a power decrease, a drag, whatever, with the hubs locked and in 2wd, then something is pretty pooched somewhere in the front.




Fred

aaronk

I'll get new drain and fill plugs and change the oil in the front diff. before I go tearing in to too much in the front end.

As for the "drag," well that was the best word I could use to describe what's going on. When I say loss of power I mean that when climbing a hill that I can usually do easily in 4th gear w/o hubs locked I can just barely do in 4th gear with hubs locked. I am running 31's on stock gearing, and the thing is already very sluggish, so maybe turning all that stuff on the front end just drops the power that much more??

When I shift the truck in to 4WD I haven't noticed if the aforementioned "drag" is still present because in 4WD I'm not accelerating very fast and my speeds are pretty low. I regularly grease my u-joints but I don't know what condition my CV joints are in. I'm just basing their condition off the boots, which look prestine.

My99

I don't think this drag you're experiencing is abnormal - I remember a 1st gen I had did this.. I assume they all do. It's only noticeable like you said - highway speeds on hills. It feels like you have a nice headwind, but without the wind-noise.

FredTJ

I can drive with mine locked or unlocked and can't tell/fell a difference.

You shouldn't be able to, there simply isn't that much "drag" in the normally operating front end as evidenced by no increase in gas mileage with manual hubs (unlocked) vs ADD say.




Fred

thook

Yeah....I drive to Fayetteville from Winslow up highway 71 (26miles) frequently with my hubs locked. Sometimes I just don't feel like getting out to unlock them after 4whlng up and out of my drive. Anyway, there are several hills in between and I can never tell a difference in power with the hubs either way. I never have to downshift nor do I lose momentum with them locked. All I ever notice is a slight hum. Oh wait....that's just me and a little Arlo Guthrie.

(Actually, yes....there is a slight hum...which sometimes I don't even notice.)

MMA_Alex

The only time i notice "drag" with em locked in is when stopped uphill, and it is less affected by the hill, but come to think of it I think i've always been in 4x4 when I experienced that...

The drag should be pretty minimal. The add trucks actually spin the halfshafts too, and i doubt they'd be doing it.

Chuckracer

I'm in the same situation here in upstate NY - I often have to drive in nasty snowy conditions that require four wheel drive, but also highway running in the same trip that doesn't. I leave the hubs locked in when I think I'll need four wheel drive, and my half-shafts are brand new re-mans, both sides. The rest of my front end and drive line is in great shape.

Indeed, I feel the additional drag when locked in. It's subtle, but definitely there. The "hum", too.

I'd say it's normal.

Jay351

I would start lookin at things, I dont notice hardly if any difference when driving with the hubs locked/unlocked. How often do you put it in 4wd?


ADD + manual hubs = the ultimate combo. Fuel savings, shift on the fly 4wd and stronger cv joints.

aaronk

Bought the truck in August, this last week was the first time I put it in 4WD for any amount of time other than when I bought it to make sure that everything was working okay.

I drove with the hubs locked 70 miles and in actual 4WD for another 15 miles.

grayguy

I know my 89' does this same thing. When I'm in 2wd with the hubs locked, it drags, vibrates, and take more power to get around. There are several hills I can take in 4th with the hubs unlocked, but have to drop to 3rd when they are...i guess I should be concerned?

Jay351

things might be all gummed up. Start pulling things off and cleaning.

Diesel_Freak

You have a problem...

Something to ask yourself is : do I fell drag when coasting? If you do you have an issue. If you're in 2wd with the hubs locked you're not turning the front D-shaft with the engine (under acceleration/load) so there's no mechanical connection. Sure the Diff is being turned by the wheels rotating so in theory there's more resistance because of the added rotationaol mass but not enough IMO to really feel as a "drag" if everything is working well.

On a related note, something to watch is the bushing/locating bolt that holds the diffup on either side of the front diff cradle. Basicly I replaced a CV joint thinking that it was hosed because I lost one of these bolts. It caused all of the issues you're having, and it was letting the front D-shaft rub on the sway bar. Now, fixed with a new Toyota part (read: NOT a bolt and washer I band-aided it with) I have NO drag in 2wd hubs locked or unlocked.

Cheers

Dave

fierohink

You mention that there is a theory to rotational mass being added, but what you are forgetting is that you are going from basically nothing spinning up front other then the wheels at the wheel bearings, to now you're turn the cvs, the diff, and the front drive shaft. If you turn the axle the driveshaft will spin too, as well as the gears in the transfer case. All these added weight and some parts sitting in a very viscous fluid will cause the truck to have added drag.

A stock 22re doens't have a whole lot of power to start with. I can notice the difference driving whether I have a passenger or not.

grayguy

Well, I was pretty sure that it wasn't normal, but i have so many front end issues, I didn't really care. I need rotors, calipers, I think a CV is starting to go, and I have a bent wheel (bought from the junk yard that way after one of mine rusted out last week). I have every intention of fixing all these issues, But right now I can't afford the down time, cause my other vehicle wont start in the cold (after market standalone ECU + untuned fuel map + cold weather= ftl)

I'll be sure to check into the diff mount bushings too.

Flash319

I don't understand how you guys can say that there is no drag between locked and unlocked and also a loss of power. Do you know how much power loss there is in a drive line? A lot! that is why "my engine has 300 horse power" don't mean sh$t unless it is measured at the wheels! 4X4 means two drive lines and you are also not putting power through the "gear reduction" when your hubs are locked and not driving in 4 wheel drive.

Bold statement ahead.............


I would say if your hubs are locked you would be saving gas having it in 4 wheel drive instead of 2. I will have to talk to Myth Busters about this one...........

FredTJ

Of course, with you statement above, obvious written without too much thought put into it, you're completely ignoring the fact that with only the front hubs locked and in 2wd you're not turning anything in comparison to the rear driveline, from the engine to the rear wheels.




Fred

Flash319

You are turning all the same thing you are turning as if you were in 4 wheel drive just backwards (on non ADD) Fred. Yes the trans accounts for a lot of total loss but the driveshaft, diff gears, CV joints (4 of them) have great loss as well, and will account for a loss in power.