I don't know what the problem is!

[drbrady]

I have a 1978 FJ40 with a SBC 350 that I just finished rebuilding (yeah I know "where are the pictures ?", they are coming). Anyways on its first road trip, 1st, 2nd gears seem to be fine. 3rd revs pretty high and 4th gear I dont dare push any harder. When I got into 4th gear and accelerated up to 35ish the engine seems to be running at an extremely high RPM and I dont dare push it any harder. I am certain it is not a carb issue since I just went and bought a new one and the problem is still there. Does anyone ahve any suggestions? My only other thought would be that the clutch could be slipping or I have a gearing problem.

 

[Martian]

In 4th gear at 35 mph your engine is running at a high RPM??? Is the tcase in low?

 

[JohnnyC]

x2 tcase in low?

or


clutch slipping...are you getting a burt smell?

 

[weez440]

i would say it almost sounds like clutch slippage.

 

[drbrady]

So with clutch slippage, is there any adjustments to try or does it need a new disc?

Checked the T-case it is in H2.

 

[Isaacjohnstar]

Does it slip when you dump the clutch? Or does it give you whip lash still?
If it does slip I would say new disk and pressure plate. You might need to get the flywheel turned as well. Downy has a stout clutch package for a good price if that's what it is.

 

[Texx]

You can check to see if the clutch is slipping by slowly engaging the clutch in 4th gear from a stop. If the engine revs climb, bad clutch. If the vehicle stalls without revs increasing, not so much. Otherwise, check your transfer linkage, are you able to easily shift between hi and lo?

 

[CruzinGuam]

Your problem sounds like clutch slippage cuz my FJ40 (SBC as well) was doing the exact same thing. Well anyways found that oil leaked from the tranny front seal onto the disc. So I ordered myself a Centerforce Dual friction clutch from summit for $269 and it pretty much solved my problem. Don't forget to get the flywheel size if you do order and also get the fly wheel resurfaced.

 

[drbrady]

Not sure if this is contributing to the problem, but a couple of you mentioned T-case stuck in low. Well turns out I can't even get the t-case to shift to low. From H2 to H4 no problem smooth as can be, but it will not go into 4L. So lets add this to the now growing list of problems and if any one has a fix I'm all ears.

 

[Martian]

Try what Texx suggested and let us know. So we can confirm whether or not your clutch is slipping.

T-case problem may be unrelated... perhaps a problem with the linkage.

 

[albee]

Not sure if this is contributing to the problem, but a couple of you mentioned T-case stuck in low. Well turns out I can't even get the t-case to shift to low. From H2 to H4 no problem smooth as can be, but it will not go into 4L. So lets add this to the now growing list of problems and if any one has a fix I'm all ears.

unhook the linkage to the tcase and try shifting it directly.
Good luck Albee

 

[drbrady]

Okay, dead stop, 4th gear, engine does not rev in fact acts just like it would if you let the clutch out in 1st without using the gas pedal. Small stutter, with a little gas takes right off and drives fine.

drove around, only smell I can tell is a little smoke from the engine

 

[drbrady]

Guys I can't thank you enough!! Looks like the 4WD shifter was all out of wack and locked in 4L. A little elbow grease, adjusting, and some forced submission with a hammer and BAM, everything functions as it should, I can even go fast than 35 now.

I will be posting again first with some pics and I'm sure some future problems.

Again thanks guys have a great weekend!