10/'79 FJ40 (1 Viewer)

[OhioFJ]

Greetings all -

I'm looking for a bit of guidance. Something bad is up with my truck - I'm not sure how to diagnose the problem. Stock 10/'79 FJ40.

I noted a recent abrupt loss of power across all gears. I can barely make it up a hill in 2nd. As I give it more power the engine will rev appropriately but the power doesn't appear to be making it to the drivetrain. When I first noted the problem I also noticed a burning odor. I had the bell housing cover off and the area around the clutch had the same smell, but nothing looked amiss. Not that I know what I'm looking for.

I can shift smoothly through all gears and all transfer case positions. Engine runs well with good compression and vacuum. relatively new clutch master and slave.

I'm thinking it must be something with the transfer case, but I'm not sure what steps to take to confirm this.

As an aside I noticed that I had been driving with one of the front wheel hubs locked, but it was in H2 so I don't think that's the end of the world..

Any help really appreciated.

 

[snaggletto]

Any time the engine increases revs, but there is no increase in speed, then the clutch is bad. The burning smell is even more evidence.

 

[Pighead]

relatively new clutch master and slave.

Wondering if your clutch needs to adjusted to fully engage?

 

[OhioFJ]

Any time the engine increases revs, but there is no increase in speed, then the clutch is bad. The burning smell is even more evidence.

That’s what I was suspicious of. Difficult job?

 

[OhioFJ]

Wondering if your clutch needs to adjusted to fully engage?

I had replaced it months ago and had no issues - it shifts without a problem. I’ll run through the fsm again and check specs.

 

[73FJ40]

Oil on the clutch surfaces?

 

[OhioFJ]

Oil on the clutch surfaces?

will inspect - would this be visible with just the bell housing removed?

 

[erics]

you gotta remove the tranny to remove the clutch components, and then the flywheel to remove the bellhousing (which you shuldnt need to do.

since most recent change was the new clutch master and slave, I'd look at the slave for misadjustment keeping clutch slightly disengaged-enough for pressure plate to slip, like slave piston being bound up and not fully returning to starting position?

 

[73FJ40]

you gotta remove the tranny to remove the clutch components, and then the flywheel to remove the bellhousing (which you shuldnt need to do.

since most recent change was the new clutch master and slave, I'd look at the slave for misadjustment keeping clutch slightly disengaged-enough for pressure plate to slip, like slave piston being bound up and not fully returning to starting position?

I suspect @OhioFJ meant the inspection cover bolted to the bell housing..

 

[77mustard40]

I think something is up with that clutch install based on ‘sudden loss of power’. I think a poor adjustment would have shown up earlier and wouldn’t lead to sudden loss of power. Maybe bad components, not torquing the clutch assembly to the flywheel? Was the flywheel resurfaced and was its thickness still in spec? Possibly some of the other components were shot and reused like the fork or not replacing the throw out bearing. Was the ream main seal done with the clutch work? Who did the clutch work, reputable shop?

I did my 77’s clutch a couple winters ago and it took this old man about a month to knock it out, but there was some other while you are there work added in. It was the first clutch replacement since mine was purchased in ‘85 so possibly yet original clutch. The clutch fork was toast, the wire retainers were MIA and and it was badly worn from all the extra movement.

 

[OhioFJ]

I think something is up with that clutch install based on ‘sudden loss of power’. I think a poor adjustment would have shown up earlier and wouldn’t lead to sudden loss of power. Maybe bad components, not torquing the clutch assembly to the flywheel? Was the flywheel resurfaced and was its thickness still in spec? Possibly some of the other components were shot and reused like the fork or not replacing the throw out bearing. Was the ream main seal done with the clutch work? Who did the clutch work, reputable shop?

I did my 77’s clutch a couple winters ago and it took this old man about a month to knock it out, but there was some other while you are there work added in. It was the first clutch replacement since mine was purchased in ‘85 so possibly yet original clutch. The clutch fork was toast, the wire retainers were MIA and and it was badly worn from all the extra movemen

I think but can not confirm that the clutch is original to the vehicle. The only clutch related work that I have done is replace the slave and master cylinder - this was last fall. I replaced it because the engagement was at a very high point when pressing the pedal. The problem was fixed after replacing the master and slave.

Based on what you guys are saying I'm suspicious that the clutch itself has gone bad, but I will check the slave as @erics has suggested.

Going to start wrapping my head around whats involved in replacing a clutch.

 

[OhioFJ]

I suspect @OhioFJ meant the inspection cover bolted to the bell housing..

Yes the inspection cover, thank you for clarifying.

 

[pb4ugo]

I suspect your cutch is shot. Replacing the master and slave was just a bandaid and bought you some time.

 

[77mustard40]

I think mine was original as well. Im not familiar with a 79 but I gutted the interior on mine to get the Trans Tunnel cover removed and used a tranny jack to get the tranny/transfer case out. Did rear main seal, pulled my gas tank and cleaned and repainted that area and the floorboards before reinstalling with new fuel lines. First timer for me but I’m happy I did it myself. I even found an original key that had slipped down below the gas tank, great place to hide a key if never need to look for it.

 

[snaggletto]

As mentioned. Check and double check all adjustments. Look up through inspection while someone actuates the clutch. Maybe post some pics of the clutch fork and throw out bearing and more experienced eyes may detect an issue. You have to remove trans and transfer to replace the clutch, so it’s not a small job.

Clutch wear should happen over time, not just overnight.

 

[OhioFJ]

As mentioned. Check and double check all adjustments. Look up through inspection while someone actuates the clutch. Maybe post some pics of the clutch fork and throw out bearing and more experienced eyes may detect an issue. You have to remove trans and transfer to replace the clutch, so it’s not a small job.

Clutch wear should happen over time, not just overnight.

Thank you - will check. I have a feeling that it has been failing for a bit as I had something similar happen a few weeks ago. I think it must have finally given up the ghost.

 

[OhioFJ]

Any idea why a clutch kit from cityracer is $185 and the same apparent kit from cruiser outfitters is $228?

Seems like both are Aisin and include the clutch pressure plate, disc, throwout bearing, pilot bearing and alignment tool.

Am I missing something?

 

[Pighead]

Could be the difference in bearing manufacturer...

 

[Pighead]

I still wonder if your clutch master and/or slave was, and is, not adjusted out all the way. So that the clutch was still resting on the throw out bearing some and not engaging the flywheel fully.
New cups in the cylinders will change the engage and release points of the disc, and they will change more as they break in.
The clutch may have been slipping some for a while and you just started noticing it a few weeks ago.

 

[OhioFJ]

I still wonder if your clutch master and/or slave was, and is, not adjusted out all the way. So that the clutch was still resting on the throw out bearing some and not engaging the flywheel fully.
New cups in the cylinders will change the engage and release points of the disc, and they will change more as they break in.
The clutch may have been slipping some for a while and you just started noticing it a few weeks ago.

Could be - I'll take some photos today. If I recall the only specs in the FSM had to do with the pedal height in the cabin which is what I went by.

Thank you again.