Putting together a 4:1 (teralow)

[BrettM]

LP60....I put too many miles on my rig for a TrueHi9, or HP 60 for that matter.

What's the concern? It seems Hi9 has the oiling issues dealt with, and I can't imagine strength being a concern... Keep an eye on Eric's, his Hi9 is in his DD...

 

[CRASH]

What's the concern? It seems Hi9 has the oiling issues dealt with, and I can't imagine strength being a concern... Keep an eye on Eric's, his Hi9 is in his DD...

I haven't talked to the TH9 people personally, but I heard second-hand that it was not recommended for DD duty. If I heard wrong, I'd love to be corrected. Maybe I need to put in a call, since I seem to be the source for diff questions around here.

I thought Eric was running the Currie HP9?

 

[CRASH]

I'm curious now,,,, I've been thinking of going to the 8.8 and hadn't heard much bad about them but now?? What size tire are you running?

35.

The 8.8 is great diff in many respects. If falls short in a couple of areas, though. The carrier bearings are on the small side when compared to a 9" or even a 44 for that matter, and are much smaller than a 60. By far, however, the case and tubes are the weakest link. I think to use an 8.8 hard requires some prep work, including fully welding the tubes to the case, and then trussing the case and tubes together. Also, I would definately run a crush sleeve eliminator kit when you set up the gears, and I would get away from the flanged yoke assembly and get a real yoke that affixes the joint with U-bolts. If you are going to be sending serious power through the 8.8, I would also want to get some larger carrier bearing caps, very common in the Mustang drag scene.

I should note that ARB has addressed the weak link in the old 8.8 ARB by making the case 2 pieces instead of 3, an by adding a 3rd side gear to the assembly to spread torque loads over a larger tooth contact area.

 

[kleake]

35.

The 8.8 is great diff in many respects. If falls short in a couple of areas, though. The carrier bearings are on the small side when compared to a 9" or even a 44 for that matter, and are much smaller than a 60. By far, however, the case and tubes are the weakest link. I think to use an 8.8 hard requires some prep work, including fully welding the tubes to the case, and then trussing the case and tubes together. Also, I would definately run a crush sleeve eliminator kit when you set up the gears, and I would get away from the flanged yoke assembly and get a real yoke that affixes the joint with U-bolts. If you are going to be sending serious power through the 8.8, I would also want to get some larger carrier bearing caps, very common in the Mustang drag scene.

I should note that ARB has addressed the weak link in the old 8.8 ARB by making the case 2 pieces instead of 3, an by adding a 3rd side gear to the assembly to spread torque loads over a larger tooth contact area.

Crash, that is good info to know before I do the swap.... Thank you!!!

 

[BrettM]

I haven't talked to the TH9 people personally, but I heard second-hand that it was not recommended for DD duty. If I heard wrong, I'd love to be corrected. Maybe I need to put in a call, since I seem to be the source for diff questions around here.

I thought Eric was running the Currie HP9?

I've seen the TrueHi9 people say a number of time on Pirate that they're fine for DDs, and Eric is running one in his DD on 37s.

And as far as strength, apparently a number of comp teams were trashing HP60 gears every couple comps, but now are switching to Hi9s and supposedly there has still yet to be a failure. Between the greater pinion offset and the thrust block (2 available for big-block type power) they are very strong. You would certainly save a good amount of weight vs. the 60 (the Hi9 is also available in Al) and tons of driveshaft clearance.

 

[2xtreme]

I am fairly certain the chevy np231c has wide chain. I'll look it up in the books when I go to work tomarrow to verify. It also has the 6 planetary that the np241 has. Both should interchange with the np231j. I'm going to do this set up along with a 32 spline output shaft with a 231 doubler and see how long it holds up. I can get the parts real cheep and when I break the 231 with 7.4:1 gearing I'll spring for a d300.

What did you find out?
I am in the process of deciding to rebuild my 231 or replace with something else. That might be a good option? Anyone else done this?
THanks,
Michael

 

[CRASH]

I've seen the TrueHi9 people say a number of time on Pirate that they're fine for DDs, and Eric is running one in his DD on 37s.

And as far as strength, apparently a number of comp teams were trashing HP60 gears every couple comps, but now are switching to Hi9s and supposedly there has still yet to be a failure. Between the greater pinion offset and the thrust block (2 available for big-block type power) they are very strong. You would certainly save a good amount of weight vs. the 60 (the Hi9 is also available in Al) and tons of driveshaft clearance.

And my infants college fund would be out $2,100. LP 60 = >$1,200 w/ ARB and alloy 35 spliners, FF 14 bolt ends.

I'm very willing to be corrected or better informed on TH9's for DD use. As I said, I heard it from someone who claimed to have talked to the owner of TH9 about it. Maybe we can get the TH9 guy to post on about it. I really feel bad about corrupting Ketchup's thread with this stuff. Maybe I should move this junk out of here?

 

[CRASH]

To bring this back on topic, I actually DID call Tera about using the 4-1 behind the NV 4500, and they said that was not a happening deal, contrary to Kleake's assertion that it would actually be EASIER on the parts behind it.

300 ft/lbs x 6.3 = 1890 ft/lbs. That's a big negative on the planetary set.

 

[kleake]

To bring this back on topic, I actually DID call Tera about using the 4-1 behind the NV 4500, and they said that was not a happening deal, contrary to Kleake's assertion that it would actually be EASIER on the parts behind it.

300 ft/lbs x 6.3 = 1890 ft/lbs. That's a big negative on the planetary set.

I will agree with you as well on this if you are at max traction...

The point I was trying to say earlier about it being "Easier" on the parts behind it is that if you are pushing out 1000 ft lbs of torque at the yoke, the engine and transmission are working less with the 4:1 than it would with the 2.72:1...
The planetary "IS" the gear reduction, so it will solely depend on the design and efficiency of the particular planetary to determine it's strength...

 

[BrettM]

I will agree with you as well on this if you are at max traction...

and the point we've been trying to make is that out west max traction is often available.

 

[CRASH]

and the point we've been trying to make is that out west max traction is often available.

And it's audible, as you found out.

"Pop, pop, pop, pop, pop."

 

[BrettM]

And my infants college fund would be out $2,100. LP 60 = >$1,200 w/ ARB and alloy 35 spliners, FF 14 bolt ends.

I'm very willing to be corrected or better informed on TH9's for DD use. As I said, I heard it from someone who claimed to have talked to the owner of TH9 about it. Maybe we can get the TH9 guy to post on about it. I really feel bad about corrupting Ketchup's thread with this stuff. Maybe I should move this junk out of here?

to continue the hijack...

so are you going 8 lug? if you're keeping 6, are you making or buying the conversion?

are you at least going to shave the 60?

 

[CRASH]

to continue the hijack...

so are you going 8 lug? if you're keeping 6, are you making or buying the conversion?

are you at least going to shave the 60?

Yes, including the ring gear. I should actually gain clearance over the 8.8 with this conversion. 8 lug, because:

1. I need an extra inch of width in front (8 lug does that for me).

2. I want stronger front hub bodies (GM 8 luggers are almost twice as thick as the GM 6 lugs).

3. My 6 lug wheels are trashed and I need new ones anyway.

 

[BrettM]

Yes, including the ring gear. I should actually gain clearance over the 8.8 with this conversion. 8 lug, because:

1. I need an extra inch of width in front (8 lug does that for me).

2. I want stronger front hub bodies (GM 8 luggers are almost twice as thick as the GM 6 lugs).

3. My 6 lug wheels are trashed and I need new ones anyway.

now it makes much more sense. cool.

 

[CW]

What did you find out?
I am in the process of deciding to rebuild my 231 or replace with something else. That might be a good option? Anyone else done this?
THanks,
Michael

The cooperate nazis at my store decided to do some house cleaning and got rid of over half of our parts books, so I couldn't find anything definative on the chain. The planetaries from a 231c or 241 are interchangeable with the 231j. I'll tear into a 231c as soon as I can to figure out the chain buisness.

 

[truehi9]

As far as the oiling goes we have lots of them in daily drivers with zero problems. Thanks CRASH for asking though.

We did have 1 comp guy bust an aluminum cased HI9 though. The 10 bolt mounting flange and case was smashed/busted inward from the outside due to losing a battle to a rock. The owners of that unit and us knew the iron case was better but mutually agreed to try the aluminum case for strength testing. We next day aired them an iron replacment at no charge and suggested a rock guard/skid plate.

 

[CRASH]

TH-9, thanks for chiming in.

I obviously was conversing with an asshat who didn't know better, or was talking about another unit.