BJ70 transmission noise?

webbz47 · 10-31-09, 09:31 PM

I'm hearing a noise from the transmission area of my 87' JDM BJ70. It sounds loudest during acceleration and is present in all gears. I thought it may be the clutch but possibly it is the main bearing in the transmission? Any ideas?

roscoFJ73 · 10-31-09, 11:20 PM

You need to give us a description of the noise. Whine ,rattle,scraping??
Is it there when idling?

prado t · 11-01-09, 11:56 AM

Ok put your Tranfer case in Neutral and shift gears and use the throttle (Be Gentle). These H55F groan a bit if you are lugging it a bit.

Radd Cruisers · 11-01-09, 04:28 PM

Present in all gears? Then I would suggest transfer case or rear end as the first place I'd look.

~John

webbz47 · 11-01-09, 09:36 PM

This problem is harder to pinpoint than I first suspected. The truck was running offroad today in 4WD high. Before driving home I turned the hubs and drove in 2WD. I started hearing a grinding rumbling noise along with a high pitched noise a bad throwout bearing would make, these noises continued till I arrived home. Once home I asked my son to come for a drive with me to listen to what I had heard but the truck sounded perfectly fine. With the transfer case in neutral running through all gears things sounded normal, no noises in neutral.

So I'm not sure what to think now? I know I need a clutch booster but surely this is not the cause ...and why would the noises dissapear? I need to do some more testing tomorrow in 2WD & 4WD to get it to reproduce these noises

.

boogie74 · 11-02-09, 05:09 AM

Did you check your uni joints???
Just a thought. I'm doing mine tomorrow cause there is a bit play in the uni
joints on the rear shaft. I'm hoping that will get rid of my rattles and wobbles.

webbz47 · 11-02-09, 09:41 PM

Uni-joints seem alright. I tried various combinations today but was unable to re-create any noise. Only thing I can think of is that the 4WD switch or solenoid may be intermittent causing it not to disengage properly. I will continue to monitor.

roscoFJ73 · 11-02-09, 11:32 PM

Quote:

Originally Posted by webbz47

Uni-joints seem alright. I tried various combinations today but was unable to re-create any noise. Only thing I can think of is that the 4WD switch or solenoid may be intermittent causing it not to disengage properly. I will continue to monitor.

Next time it happens try swapping the hoses at the solenoids.
Usually its a leaky or loose hose,but it normally doesnt make any weird noises if the shift mechanism isnt getting enough vacuum.
Maybe the clutch gizmo in the vac shift mechanism is worn

jake2far · 11-12-09, 07:16 AM

Quote:

Originally Posted by webbz47

I'm hearing a noise from the transmission area of my 87' JDM BJ70. It sounds loudest during acceleration and is present in all gears. I thought it may be the clutch but possibly it is the main bearing in the transmission? Any ideas?

My 1985 BJ70 started making a rumble/whining/ noise in all gears it sounded almost like tire tread road noise from aggressive tread, not related to engine speed but did follow road speed. I tried to locate it, it sounded like it was coming from the transmission area. The way I found it, put it up on stands start the engine put it in second gear and turn the throttle up till it is spinning the rear tires at a good speed, very carefully get under the rig, use a mechanics stethoscope and listen to the bearing areas in the transmission, transfer case, and rearend. I found the noise coming from the rearend input bearing, when I checked the gear oil from the rearend it had very fine metal in it, when I tore it down the input bearing was flaking on the surface of the race, rebuilt the differential and the noise went away. Picture is of a mechanics stethoscope. They are not expensive.

Hope this helps, oh yea when under the rig avoid the spinning tires.
Jim

Radd Cruisers · 11-12-09, 09:37 AM

Quote:

Originally Posted by webbz47

Uni-joints seem alright. I tried various combinations today but was unable to re-create any noise. Only thing I can think of is that the 4WD switch or solenoid may be intermittent causing it not to disengage properly. I will continue to monitor.

That should be easy to assess... next time it's making the noise, have the hubs unlocked and the 4wd disengaged and see if the front shaft turns. If it turns freely, then it's not your driveshaft making the noise.

The most common source of noise in the trans/transfer case is the output bearings in the transfer case. The other really common place to look is the pinion bearings in the rear end.

I would suggest that if you're having trouble figuring it out, then you should take it to a competent shop and have them check it out for you.

~John