H151F Rebuild (1 Viewer)

[ArmyFJ]

Rebuilding my HF1A transfer case and H151F transmission due to some issues with shifting into 2nd and some leaks. I used this link from Landcruiserclub.net as well as a 100 series FSM to guide me through this. It's not too complicated...just lots of layers. Transmission jack is a must and I also pulled the fan just to keep my radiator safe. The transmission tunnel is incredibly tight and took a good bit of wiggling around to get the transmission out.

Bell-housing with lots of love from either the engine or the input shaft...probably both.

Back side showing the reverse fork and gear. There is a good amount of burnt oil covering all the internals.

Shifter seat; pin on the top gets punched through and then the shaft can be slid out:

Oil pump with a bad o-ring and some gray RTV that was used to re-seal and then went into the feed line.

 

[ArmyFJ]

Transmission housing removed and set in vise. Some good looking burnt ends...

Marking out the shafts, detent balls & springs, and forks:

Hard to tell from this picture but the rear counter-shaft bearing is toast. The plastic cage was burnt and broken.

 

[ArmyFJ]

4th and 3rd gear:

5th gear (center):

2nd and 1st gear. Note that each one has a bevel on the front for orientation.

Reverse gear:

Both 5th and 2nd gear clutch hubs had some good burn in going on.

 

[OGBeno]

Love all the COVID projects people are taking on.

 

[ArmyFJ]

@Onur , indeed! Must seize an opportunity. Just hoping my parts aren't too delayed from shipping outside the United States.

Oil strainer treasures...RTV, bits of the shifter seat and bushing, and hub clutch teeth from 3rd gear.

Rear counter shaft bearing close-up. It is a split bearing...but not this split normally.

3rd gear clutch sleeve teeth on the trailing edge are broken on all three synchronizer cutaways. Interestingly, on later versions of the H151F these broken teeth don't exist for this gear...maybe an initial design flaw.

 

[tacocat]

Cool thread.

P.S. I hate you for being an H151F owner.

 

[dogfishlake]

Very cool. Thanks for sharing.

 

[ArmyFJ]

2nd gear bearing was smoked.

5th gear with a good bit of scoring on the needles.

Both 2nd and 5th gear hub clutches were stuck on the output shaft - burned in with oil I am guessing. Took some freezing, PB blaster and a little heat to get the press to break them free.


A majority of the parts laid out here. Getting ready to clean these and taking the case parts for hot tanking.

 

[Feistl]

How’s the input shaft?

For what it’s worth I’ve rebuilt 4 H151fs for my various cruisers and rather than trying to rebuild the original 80 series boxes, I have purchased H150Fs from VDJ79s. You can swap the input shaft and bellhousing and it bolts straight in. Gives you triple syncros on the gears and a few other improvements. I’ve paid $500au for each VDJ79 gearbox (they’ve have between 33,000-78,000kms).

Much cheaper than rebuilding the 80 series boxes and a better box overall. Also gives a slightly shorter first and second ratio which works better for off-roading.

 

[ArmyFJ]

Thanks, @Feistl. Good to know and that would be cool but shipping might be a bit much on that even if I can get it at $500. When you say triple synchro do you mean this:

 

[Feistl]

Yeah, I think so.... it’s been a few months since I last built one. All I remember is there was definitely differences in the syncros between the 80 series and VDJ79 gearboxes. The 80 series was single, the VDJ79 was triple...

The 80 series boxes I pulled down were a 92, 2x94 and a 95... so maybe the later models were different?

Either way, something to keep in mind. I remember the cost of syncros being more than $600au and didn’t include new bearings.

Also, for anyone else in the USA a VDJ79 gearbox at $500AU is less than $300usd. You can get the 80 series input shaft new for like $200usd, not a bad upgrade path. Might see what shipping is...

 

[ArmyFJ]

Could be that later years were different...

There is probably a market for those transmission here if the shipping is right or you do it in bulk.

 

[ArmyFJ]

Pulled the clutch and flywheel...I'll be replacing the rear main seal and doing the oil pan.

 

[ArmyFJ]

Rear oil seal retainer and oil pan No. 1 ready for cleaning and seal replacement.

Oil pan all cleaned up with a new gasket for the oil strainer. Oil level sensor gasket and o-ring for the dip stick broke apart as soon as I tried to remove them.

New rear main seal and oil pan No. 1 and No. 2 back in with new seals and FIPG.

 

[ArmyFJ]

Got the flywheel resurfaced. There is something very satisfying about a freshly machined piece of steel.

 

[Omsok]

Great detailed post, thanks I will be coming back to this for sure. How can you tell which version of Manual transmission is which? Are there tags, or stamps anywhere?

 

[ArmyFJ]

Since the transmission and transfer were a swap into my 80 prior to me owning it, I didn’t have a VIN to base my searches on. I had to pull apart the transmission pull some part numbers off the clutch and then cross reference pictures of parts with bearing numbers and parts diagrams. If yours is original to the vehicle - the best way is going to be to use your data plate and VIN to find out what you have.

 

[kw90surf]

Awesome, subscribed.

How would you describe the way it drove with the insides looking like that? I have an H150F with unknown km on its way from Aus so I am watching this rebuild with interest!

 

[ArmyFJ]

How would you describe the way it drove with the insides looking like that?

It wasn’t bad - just slow to go into 2nd. No issues with the other gears - despite the damage to the bearings and the substantial amount of burnt oil. While it wasn’t effecting operation noticeably - the seals where done and gear oil was leaking into the bellhousing and out the back output shaft at the oil pump housing.

About a year ago I replaced the shifter bushing and seat - they were both destroyed and that impacted shifting significantly. Cheap and very easy to fix.

I have read that Red Line MT90 is the best gear oil to use in these for smooth shifting. I bought some and will try it out after completing the rebuild. In the past, I have tried conventional 80w90, AC Delco Synchromesh, and LiquiMoly GL4 75w90 - all felt about the same in the transmission.

 

[ArmyFJ]

Reverse hub sleeve was pretty worn so I got a new one:

Parts laid out for reassembly; just waiting on the new bearings to show up.