high pinion diff probs

[soenke]

has anyone experienced problems or brakes of the high pinion front axel diff?

especially when tire sizes >35" is used?

In Germany I haven´t heard of any problems (just one guy with 35" in the sand managed to brake the diff) but most people just use tire size up to 285/75 and don´t go in the rocks....

thanks for sharing your XP....

 

[MikePL]

For tires larger than 33" (285/75/16) you will probably need to regear (put different gears in the differential).

 

[Darwood]

To my knowledge, no, I can't think of any typical failures due to 35" or 37" tires.

 

[Cruiserdrew]

They hold up to 35s just fine. The diffs I have heard of being broken (2) were being abused/jumped at the time.

 

[soenke]

For tires larger than 33" (285/75/16) you will probably need to regear (put different gears in the differential).

we did, it is 4.5:1 from a PZJ 75 inside ;p
it´s shorter then the stock set up now

-> so you haven´t heard of many breaks???

 

[montezuma]

I have seen/ heard of several guys here in Southern California breaking the stock gears in those diffs running 37-39" tireas in light weight buggy's. It seems to depend on how they're being abused, and how old the gears are. I've heard that the diffs are stronger going forward, but seem to break more easily when backing up due to reverse being the lowest gear. I don't know the validity of this, but alot of the guys who were running high pinions have switched over to low pinion V6 diffs for the front.

 

[Tapage]

Are you plan run lockers .. ? read about ARB offering great results improving the front HP 8" strengh

 

[soenke]

Tapage, we have stock e-lockers.
I just don´t know if customising the axel is worth the hassel.
We use the car for travelling, so I would prefer to use Toyota parts. If we rebuild the axel with the stronger rear Diff it has to run "the wrong way" permananty...?..

Montezuma, what is the V6 Diff?
"....switched over to low pinion V6 diffs for the front. ...."

 

[montezuma]

Montezuma, what is the V6 Diff?
"....switched over to low pinion V6 diffs for the front. ...."

It's a diff found in the back ends of v6 and turbo trucks. It's an 8" like the highpinion stuff, but low pinion. It's the same bolt pattern as the FJ80 cruiser front ends. It works well with the minitruck crowd, because the steering is on the front of the axle, but I don't know if it would fit the stock cruisers with steering on the backside of the axle. The tierod might get in the way of the pinion or flange.

 

[KliersLC]

The front diff is particularly vulnerable to breakage if you work it too hard in reverse. Attempting a snatch in reverse or hitting the throttle too hard while trying to back up a ledge could break the front pretty easily....

 

[soenke]

thanks so far.


Mini truck turbo ist the HiLux?? So they take the whole axel, dont just cut the diff out of the tube and swatch it?

Why is 8" low pinon so much stroger then high pinion ? would think once I work on the axel I go for the 9" ?

Best would be of course if you guy´s tell me not to worry. I drive quite soft and cautious.......
and would never pull something in reverse...

 

[WarDamnEagle]

OK. Don't worry.

The front hi-pinion differential has reverse cut gears to make it as strong as the rear differential going forward. Both your rear differential and your front differential, in the case of a hi-pinion, isn't as strong going in reverse because you are pulling on the "coast" side of the gears. I haven't done the math but it is generally claimed that ring and pinion gears are 30% on the coast side.

In a mini truck, Hillux, surf, etc., which run a low pinion front differential, the ring and pinion gears are running on the coast side going forward. That means that they are 30% weaker than the rear differential going forward but stronger than the rear when going in reverse.

A low pinion differential will not work on your 80 unless you change the steering. Bottom line, there is nothing to worry about!

Haben Sie dass verstanden?

 

[Aussie cruiser]

The front diff is particularly vulnerable to breakage if you work it too hard in reverse. Attempting a snatch in reverse or hitting the throttle too hard while trying to back up a ledge could break the front pretty easily....

x2
Only ones I've heard of are from snatching in reverse

 

[soenke]

OK. Don't worry.
......
Haben Sie dass verstanden?

ja habe ich ...... and I do hope you are right !

In a mini truck, Hillux, surf, etc., which run a low pinion front differential, the ring and pinion gears are running on the coast side going forward. That means that they are 30% weaker than the rear differential going forward but stronger than the rear when going in reverse.

yes, but a 9" from a 60 or old 70 will be probably stronger even working on the "coast side"...

but I am glad to hear the quintessence

 

[WarDamnEagle]

ja habe ich ...... and I do hope you are right !



yes, but a 9" from a 60 or old 70 will be probably stronger even working on the "coast side"...

but I am glad to hear the quintessence

A 9" diff won't go in the front of an 80...only in the rear.

 

[montezuma]

Plus, arent the bearings for the early 9" diffs the same size as the Hilux/ surf/ mini 4cyl. diffs.? I believe the v6 and the high pinions have larger bearings.

 

[soenke]

A 9" diff won't go in the front of an 80...only in the rear.

I know, it would be a lot of hassel, cutting the axeltubes and welding the bigger diff-housing in the 80 axel...

 

[Tapage]

which it's the opinion about the old 9.5" out from 40/60/ and few 70 series .. that it's true 9.5 and low pinion ..