DIY 4.3 Re-Gear

[bloc]

Gotta say thanks for the write-up! I just finished the swap to 4.3 diffs and 34s are much easier to turn now. For me a simple third member swap was all I did, no real need for a locker at the moment. The only part I struggled with was reinstalling the front diff, it's a tight area. Well worth the effort and if you are patient, fairly cost effective in my opinion.

No difficulty removing the needle bearing from the tundra front diff housing?

 

[Dixon Santana]

My slide hammer with a jaw attachment made very quick work of that. Three pulls got it out in one piece. The diff was super low miles so I'm guessing that made things come apart a little easier. @bloc

 

[TeCKis300]

Good stuff @Dixon Santana . Glad this thread helped you. Feel like many of us should have done this years earlier with the knowledge now available.

I just put 35s on and the gearing feels perfect. As it should because it's effectively stock gearing.

 

[Atwalz]

@TeCKis300 Got any pics of locker switches you used and where did you mount them?

 

[TeCKis300]

Sure. With so many things added, I bit the bullet and added a SwitchPros to simplify integration and wiring. Something I should have done years ago with it's overall integration that includes low voltage cut-off, short protection, programmable, BT control, etc. I hacked off the switches the Harrop came with and adapted the flying harness that is directly powered by the SwitchPros.

I believe you went with Arb Air Lockers? The SwitchPros does have the ability to be programmed such that it fires up the air compressor when a locker is activated.

 

[supercarrera]

Well I have a 4.30 gears and Tundra clamshell in the garage with a Harrop and other parts in route. After watching the Otramm video multiple times, reading this thread multiple times, and watching other gear setup videos, I'm starting to feel fairly confident I can do my own Harrop install and gear set up. Especially since Valley Hybrids is booked up for the next couple weeks.

It seems like the major potential point of pain during the rear gear setup is getting the pinion shim correct. It could take multiple tries to get it right. And from what I gather, a good starting point for shim thickness is what is being run in the vehicle's current differential setup. Is there a good source for buying the pinion shims before I start? Are there a few standard sizes that I should have on hand?

 

[KLF]

Well I have a 4.30 gears and Tundra clamshell in the garage with a Harrop and other parts in route. After watching the Otramm video multiple times, reading this thread multiple times, and watching other gear setup videos, I'm starting to feel fairly confident I can do my own Harrop install and gear set up. Especially since Valley Hybrids is booked up for the next couple weeks.

It seems like the major potential point of pain during the rear gear setup is getting the pinion shim correct. It could take multiple tries to get it right. And from what I gather, a good starting point for shim thickness is what is being run in the vehicle's current differential setup. Is there a good source for buying the pinion shims before I start? Are there a few standard sizes that I should have on hand?

Did you get an "install kit" with your gears? Usually they will include pinion shims, but maybe not for these diffs.

 

[The Crowbar]

Well I have a 4.30 gears and Tundra clamshell in the garage with a Harrop and other parts in route. After watching the Otramm video multiple times, reading this thread multiple times, and watching other gear setup videos, I'm starting to feel fairly confident I can do my own Harrop install and gear set up. Especially since Valley Hybrids is booked up for the next couple weeks.

It seems like the major potential point of pain during the rear gear setup is getting the pinion shim correct. It could take multiple tries to get it right. And from what I gather, a good starting point for shim thickness is what is being run in the vehicle's current differential setup. Is there a good source for buying the pinion shims before I start? Are there a few standard sizes that I should have on hand?

Not sure how convenient for you, but I used Pro Gear in San Diego to install my 4.88's. Quite happy with the job.

 

[supercarrera]

Did you get an "install kit" with your gears? Usually they will include pinion shims, but maybe not for these diffs.

I don't want to get an install kit because the ring and pinion already came with a crush sleeve, and seal. I can buy the bearings separately and save some money. Looks like a few vendors sell shim kits. There's one on the Nitro site with 3 shims in it.

 

[TeCKis300]

Can't say this will always work out but it has in the few times I've built Toyota diffs. I always figured if I needed a different size shim, I'd cross that bridge then. Been lucky so far to not need a different size shim.

The strategy for me has been to re-use the shim that belonged to the gear/pinion that I'm installing. Rather than the one that was in the housing. I was convinced this last time around as I was installing an '02 gearset into an '09 housing, being that many years apart, that there'd be a need for a different size shim. Worked out that everything fell in place and the pattern checked out.

If you're pressed for time once you tear things apart, you may want a shim set on hand. Or could have a local shop identified that would have the parts on hand when needed.

 

[supercarrera]

Can't say this will always work out but it has in the few times I've built Toyota diffs. I always figured if I needed a different size shim, I'd cross that bridge then. Been lucky so far to not need a different size shim.

The strategy for me has been to re-use the shim that belonged to the gear/pinion that I'm installing. Rather than the one that was in the housing. I was convinced this last time around as I was installing an '02 gearset into an '09 housing, being that many years apart, that there'd be a need for a different size shim. Worked out that everything fell in place and the pattern checked out.

If you're pressed for time once you tear things apart, you may want a shim set on hand. Or could have a local shop identified that would have the parts on hand when needed.

That seems as good a strategy as any, however I opted to start with a brand new set of gears though rather than getting them from a hundy. So I only have the current setup in the case to go by. Patsouq sells shims for around $2 each. I'll probably grab an assortment from them.

 

[TeCKis300]

That seems as good a strategy as any, however I opted to start with a brand new set of gears though rather than getting them from a hundy. So I only have the current setup in the case to go by. Patsouq sells shims for around $2 each. I'll probably grab an assortment from them.

Ah yes. Brand new is the way to go as it gives you the benefit of an overall stronger pinion. I'd agree you'll want some shim options on hand.

 

[supercarrera]

My Harrop arrived today and I'm thinking about how I'm going to secure it so it doesn't move when I start torqueing down the ring gear bolts. My current bench vise is woefully inadequate for holding it in position to attach the ring gear. @TeCKis300 did you use any creative tricks or simply use a bench vise?

 

[TeCKis300]

I had it clamped down in a press to torque.

The Harrop case is 110mm in diameter or a bit less than 4.5". Could source a new vice with that jaw size relatively cheap?

Thinking outside the box, you could potentially install it into the diff housing and jam it in various positions. Would be a bit cumbersome but could maybe use axles inserted into the diff housing and locked to hold.

 

[supercarrera]

I had it clamped down in a press to torque.

The Harrop case is 110mm in diameter or a bit less than 4.5". Could source a new vice with that jaw size relatively cheap?

Thinking outside the box, you could potentially install it into the diff housing and jam it in various positions. Would be a bit cumbersome but could maybe use axles inserted into the diff housing and locked to hold.

Actually I have that press and thought about doing it that way but I thought the press wouldn't be sturdy enough. Did you bolt it to the floor?

 

[TeCKis300]

I didn't have it bolted to the floor. It wasn't that bad if I remember. One thing that helps is to span the handle of the torque wrench across the diff, rather than creating more leverage with the handle radially outwards, if that makes sense.

 

[bloc]

I’ve bought a chunk of angle iron and drilled two holes in it to line up with the bolt holes on the diff driveshaft flange. Then toss the carrier into the case, get the mesh close enough, and let the gears plus angle iron hold the carrier still enough to torque things up.

Check out what “Zuk” does with his gear setups for some general ideas.

 

[supercarrera]

The FSM calls for new bolts for the extension tube on the front carrier. Do you guys think this is really necessary? Of course Stevens Creek Toyota doesn't have them in stock and I don't feel like waiting three days for them to come in.

 

[grinchy]

The FSM calls for new bolts for the extension tube on the front carrier. Do you guys think this is really necessary? Of course Stevens Creek Toyota doesn't have them in stock and I don't feel like waiting three days for them to come in.

View attachment 2628659

What’s the specified torque?

 

[supercarrera]

What’s the specified torque?

It says "48 ft-lbs or less"