hj61 gearbox rebuild

goldchaser · 12-17-06, 11:03 PM

Hi guys goldchaser from oz here,havent posted alot but ive been reading posts and got alot of handy info off this site,anyway im doing up a hj61sahara,I havent done much yet but the next 9 months or so it has to be done to head over to west oz in early 08,it was meant to be early next year but im in the middle of a large house reno so we have put it off till next year,ive got hold of a 61 sahara with no rust in the roof,400,000 klms,its been running around the city all its life,I havent done a compression test on the motor yet but it goes great but blows a bit of blue smoke and slight tap until oil pressure comes up on the motor,seems to have alot of compression braking,I planned on rebuilding the motor so this doesnt worry me too much.If im lucky it might just need turbo,injector pump and head doing,if bootom end is good I could put it off for a couple of years,the tap when its cold is something in the top end,could be an injector.
One question I would like to ask you guys is about the gearbox rebuild,I can spin a few wrenches,more on motorbikes really!Im gonna do everything exept the motor and box etc.But if this thing has been running around the city all its life and rarely been in 4x4 do I do just the gearbox or box and transfer? So what im also asking is when in 2wd is the transfer case working or is it completly disengaged,this is something ive never really known about 4wds,because if it is just sitting idle when in 2wd and this car has rarely been in 4wd I dont see any reason to rebuild the transfer case also.
One other thing before I go,just in case any of you blokes might be interested theres a 12ht for sale on outerlimits 4x4 forum here in oz,he says 286,000 klm perfect condition,$5500,its in sydney too so sea freight might not be so difficult,just thought i'd let ya's know.

cheers goldchaser

roscoFJ73 · 12-17-06, 11:13 PM

Hi GC. The standard wisdom is to do both the gearbox and the t;case when rebuiling .
The t/case has to come apart anyway when you separate it from the gearbox.
The t/case is always in use in either high or low ratio except when you knock the t/case into neutral to use the PTO.

Generlly you know when they need a rebuild,city driving does not guarrantee an easy life.
Usually the synchros wear and make it hard to shift even when warm,5th sometimes jumps out and they whine and scream their ass off.

If you going to do the engine up ,do the whole lot. Increasing the compression by rebuilding the head on an old engine usually means an early death for the bottom and vice versa.
They take a long time to die so go easy on it and it may go for years.

brownbear · 12-18-06, 12:43 AM

I wouldn't touch the cases unless they need it. Feel the output shafts for movement etc..how does it drive?

The engine should just get a servicing, like injectors re-done. No point doing the IP pump if it is working fine. They should go life of the engine.

The engine should get a compression test and oil pressure check.

Maybe the oil relief needs looking at.

When your ready do the entire rebuild, engine, tcase and tranny. Have a vehicle ready to do another 500K ................... long bloody time.. How many KM's do you average a year?

70sguy · 12-18-06, 12:47 AM

You will want to take a close look at the spline wear on the transmission output shaft and Tcase input gear interface. 12H-T is a torquey motor and in city driving it can really trash those splines. There is an aftermarket 1 piece input gear/spacer and PTO gear available that you can use if the splines are bad, you get about a 3.5" purchase on the splines rather than the 1" on the stock separate input gear/spacer/PTO gear set up.

goldchaser · 12-22-06, 12:33 AM

Yeah thanks guys welli'll definetly be doing box and transfer then.
yesterday I done the valve adjustments on the motor and there was a pool of oil in the turbo so I know where most of the blue smoke is coming from now,but I still have this tap for about 1-2 minutes when its cold,I was hoping it was a valve adjustment,hopefully it will be an injector.
I used a trick I read about on here to find tdc,jacked one wheel up and 5th gear then turn the wheel,real easy,marked the pully and had the missus watch for when it was lined up.

cheers dave

12-17-06, 11:03 PM	#1
goldchaser IH8MUD Regular Join Date: Oct 2005 Location: land of oz Posts: 211	hj61 gearbox rebuild Hi guys goldchaser from oz here,havent posted alot but ive been reading posts and got alot of handy info off this site,anyway im doing up a hj61sahara,I havent done much yet but the next 9 months or so it has to be done to head over to west oz in early 08,it was meant to be early next year but im in the middle of a large house reno so we have put it off till next year,ive got hold of a 61 sahara with no rust in the roof,400,000 klms,its been running around the city all its life,I havent done a compression test on the motor yet but it goes great but blows a bit of blue smoke and slight tap until oil pressure comes up on the motor,seems to have alot of compression braking,I planned on rebuilding the motor so this doesnt worry me too much.If im lucky it might just need turbo,injector pump and head doing,if bootom end is good I could put it off for a couple of years,the tap when its cold is something in the top end,could be an injector. One question I would like to ask you guys is about the gearbox rebuild,I can spin a few wrenches,more on motorbikes really!Im gonna do everything exept the motor and box etc.But if this thing has been running around the city all its life and rarely been in 4x4 do I do just the gearbox or box and transfer? So what im also asking is when in 2wd is the transfer case working or is it completly disengaged,this is something ive never really known about 4wds,because if it is just sitting idle when in 2wd and this car has rarely been in 4wd I dont see any reason to rebuild the transfer case also. One other thing before I go,just in case any of you blokes might be interested theres a 12ht for sale on outerlimits 4x4 forum here in oz,he says 286,000 klm perfect condition,$5500,its in sydney too so sea freight might not be so difficult,just thought i'd let ya's know. cheers goldchaser

12-17-06, 11:13 PM	#2
roscoFJ73 Diesel for blood Join Date: Jul 2003 Location: west australia Posts: 6,523	Hi GC. The standard wisdom is to do both the gearbox and the t;case when rebuiling . The t/case has to come apart anyway when you separate it from the gearbox. The t/case is always in use in either high or low ratio except when you knock the t/case into neutral to use the PTO. Generlly you know when they need a rebuild,city driving does not guarrantee an easy life. Usually the synchros wear and make it hard to shift even when warm,5th sometimes jumps out and they whine and scream their ass off. If you going to do the engine up ,do the whole lot. Increasing the compression by rebuilding the head on an old engine usually means an early death for the bottom and vice versa. They take a long time to die so go easy on it and it may go for years. __________________ HZJ75 cab chassis 95 model ,stocker FJ73+1HZ Diesel NEW GEARBOX 1HZ =same power as 3F with 30% better fuel economy 2in Dobinsons lift.Powerdown adj shocks 33 in BFG A/T HJ61 with slidin windas regrettfully SOLD:( Volvo 740 GL

12-18-06, 12:43 AM	#3
brownbear Mod in Hibernation Join Date: Sep 2004 Location: Where diesels purr and turbos whine TLCA# 15584 Posts: 6,183	I wouldn't touch the cases unless they need it. Feel the output shafts for movement etc..how does it drive? The engine should just get a servicing, like injectors re-done. No point doing the IP pump if it is working fine. They should go life of the engine. The engine should get a compression test and oil pressure check. Maybe the oil relief needs looking at. When your ready do the entire rebuild, engine, tcase and tranny. Have a vehicle ready to do another 500K ................... long bloody time.. How many KM's do you average a year? __________________ -84 BJ60, Finally on the FN road! -91 FJ80, wife's ride Iron Butt award winner of the Cruise Moab 08 !

12-18-06, 12:47 AM	#4
70sguy IH8MUD Addict Join Date: Nov 2003 Location: Greendale B.C Canada Posts: 563	You will want to take a close look at the spline wear on the transmission output shaft and Tcase input gear interface. 12H-T is a torquey motor and in city driving it can really trash those splines. There is an aftermarket 1 piece input gear/spacer and PTO gear available that you can use if the splines are bad, you get about a 3.5" purchase on the splines rather than the 1" on the stock separate input gear/spacer/PTO gear set up. __________________ 93 1HD-T powered FZJ80-Extreme valve body-Walbro-ARB- Snork-OME- SOLD! 97 FZJ80 Antique Sage 40th, bone stock. 1HD-FT 5spd conversion starting soon VW A4 Jetta TDI My other diesel is a Locomotive www.gscruiserparts.com

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12-22-06, 12:33 AM	#5
goldchaser IH8MUD Regular Join Date: Oct 2005 Location: land of oz Posts: 211	Yeah thanks guys welli'll definetly be doing box and transfer then. yesterday I done the valve adjustments on the motor and there was a pool of oil in the turbo so I know where most of the blue smoke is coming from now,but I still have this tap for about 1-2 minutes when its cold,I was hoping it was a valve adjustment,hopefully it will be an injector. I used a trick I read about on here to find tdc,jacked one wheel up and 5th gear then turn the wheel,real easy,marked the pully and had the missus watch for when it was lined up. cheers dave