6bt cummins NV4500 1996 LX450 swap

[Major Tom]

Nice work.

Nv4500's never get better with time. They shift the best they ever will right after a quality rebuild.

Did you rebuild it or did you have it done by a shop? What was the main and countershaft clearance set to and what was the method used to check it?

If you could explain in detail what the poor shifting is that you are experiencing I can help troubleshoot. I have extensive experience with these transmissions. Describe if the issue is same in all gears or different and same putting it into gear at a stop vs shifting while moving on the road.

Thank you for the help. I'll drive it tomorrow and make a detailed list and post. The trans had fresh gears and syncos when I purchased it ten years ago. It has set in my shop since then. I had an individual that works alone rebuilding transmissions put the modified mainshaft in for me. He was suppose to have inspected everything while inside it and replaced bearing etc. I'm assuming he set the clearances correctly.

 

[Major Tom]

Nice work.

Nv4500's never get better with time. They shift the best they ever will right after a quality rebuild.

Did you rebuild it or did you have it done by a shop? What was the main and countershaft clearance set to and what was the method used to check it?

If you could explain in detail what the poor shifting is that you are experiencing I can help troubleshoot. I have extensive experience with these transmissions. Describe if the issue is same in all gears or different and same putting it into gear at a stop vs shifting while moving on the road.

I've been putting some miles on the truck and shifting is getting better. I'm wondering if there was still some air in the system that has bled out while in operation. The clutch is even feeling different. I installed the 10% overdrive gear and a part-time 4wd kit. Here's my observations as of today:

Clutch operation:

• Clutch pedal is pushed to the floor.
• Shifter moved to first - slight resistance felt when moving to first.
• Pedal is released maybe two inches (or one-third of the total moment) before it bites and engages.

Shifting: shifting seems fine from gear to gear with some slight resistance. Fifth has been hard to find a few times.

Fifth gear noise: I'm hearing a noise only in fifth gear. Right now, I am cruising at 60 mph in fifth gear and running above 2000 rpm's (I still need to calibrate my dakota box). When I let off the throttle and slow down somewhat to a lower speed, I'm hearing a random, occasional noise that sounds something like a wrench hitting the center dif. It's not a loud noise but can be heard through my transmission tunnel (I haven't sealed it off yet).

 

[PIP]

Shifting sounds normal although 5th should not be hard to find. Sounds like air in clutch hydros worked out.

Noises like that are a little impossible to troubleshoot unless driving in person.

In 5th your drivetrain resist the engine torque the most. The noise could be something on the engine/transmission hitting the body as the engine rotates under torque.

If you lug it in 4th and it doesn't happen try lugging it in 3rd. If it makes the noise in 3rd and 5th then it's in your transmission.

Nv4500s have a long list of things that can be put together wrong or fail related to 5th gear. 5th gear spline failure effects each and every one of them, but I've also seen the countershaft 5th c-clip pop off, spacers and pins forgotten, the 5th shift fork rail housing bore in the case wear out and a common one is people simply not installing mainshaft 5th gear and nut correctly causing it to loosen immediately. This could be an innocent mistake. I've had it happen with a mainshaft that was machined wrong and the nut bottomed out without fully bearing on the gear.

I've seen dodges where a noise was 100% for sure coming from the bellhousing and the problem turned out to be bad bearings in the 241 transfercase.

While your driving try to find things that cause the noise to happen. If you do, post them up.

You are running Castrol Syntorq or Redline MTL or MT85 correct?

If you drain some nv4500 fluid into a clear cup and you see any glitter at all you have a trans problem.

 

[Major Tom]

Shifting sounds normal although 5th should not be hard to find. Sounds like air in clutch hydros worked out.

Noises like that are a little impossible to troubleshoot unless driving in person.

In 5th your drivetrain resist the engine torque the most. The noise could be something on the engine/transmission hitting the body as the engine rotates under torque.

If you lug it in 4th and it doesn't happen try lugging it in 3rd. If it makes the noise in 3rd and 5th then it's in your transmission.

Nv4500s have a long list of things that can be put together wrong or fail related to 5th gear. 5th gear spline failure effects each and every one of them, but I've also seen the countershaft 5th c-clip pop off, spacers and pins forgotten, the 5th shift fork rail housing bore in the case wear out and a common one is people simply not installing mainshaft 5th gear and nut correctly causing it to loosen immediately. This could be an innocent mistake. I've had it happen with a mainshaft that was machined wrong and the nut bottomed out without fully bearing on the gear.

I've seen dodges where a noise was 100% for sure coming from the bellhousing and the problem turned out to be bad bearings in the 241 transfercase.

While your driving try to find things that cause the noise to happen. If you do, post them up.

You are running Castrol Syntorq or Redline MTL or MT85 correct?

If you drain some nv4500 fluid into a clear cup and you see any glitter at all you have a trans problem.

Thank you for the input. I will take your advice and check the oil and keep testing the issue. I'm using Amsoil SAE 75W-90 100% synthetic Manual transmission and gear lube.

 

[mjosoba]

Thank you for the input. I will take your advice and check the oil and keep testing the issue. I'm using Amsoil SAE 75W-90 100% synthetic Manual transmission and gear lube.

Is it specifically for the NV4500? There are only a handful of fluids that work for them, unless the syncros have been switched to brass.

The ones @PIP mentioned, and MAYBE one or two more are the only ones that are ok. I doubt this would be causing any issues yet, but long term it will.

 

[Major Tom]

Is it specifically for the NV4500? There are only a handful of fluids that work for them, unless the syncros have been switched to brass.

The ones @PIP mentioned, and MAYBE one or two more are the only ones that are ok. I doubt this would be causing any issues yet, but long term it will.

@mjosoba since you and @PIP have mentioned the fluid type, I’m going to look closer into the amsoil. I was aware that the fluid type in the nv4500 was important. It seemed like using this product would simplify my maintenance because it could be used in the axles, center diff and nv4500. Here’s a photo of the back of the amsoil product. The label and info on their website specifically talks about nv4500 application.

 

[Major Tom]

My son is showing me how to write a business plan with Chat gpt.


Me…..

Hey Chat gpt, explain the process of installing a Cummins 6bt in an 80
Series Landcruiser…….

10 seconds later, Chat gpt’s response……

Installing a Cummins 6BT motor into an 80 series Land Cruiser involves several steps and requires a certain level of mechanical expertise. Here's a general overview of the process:

1. Engine Selection: Start by acquiring a Cummins 6BT engine that is suitable for your Land Cruiser. Ensure that the engine is in good condition and matches the specifications required for your vehicle.

2. Gather Required Parts: Along with the engine, you'll need various components to complete the installation. This typically includes an adapter plate, custom engine mounts, wiring harness, fuel system components, cooling system modifications, and exhaust modifications.

3. Prepare the Land Cruiser: Remove the existing engine and associated components from the Land Cruiser. This may involve disconnecting the battery, draining fluids, removing the radiator, and disconnecting the drivetrain components.

4. Fit the Adapter Plate and Engine Mounts: Install the adapter plate onto the back of the Cummins engine. This plate allows you to connect the engine to the Land Cruiser's transmission. Ensure it is aligned correctly and securely bolted. Fabricate or purchase custom engine mounts that will properly position the engine within the Land Cruiser's engine bay.

5. Modify the Cooling System: Adapt the cooling system to accommodate the Cummins engine. This may involve fabricating custom brackets, modifying the radiator or acquiring an aftermarket radiator, and connecting the necessary hoses and fittings.

6. Modify the Fuel System: Adapt the fuel system to work with the Cummins engine. This usually includes installing a lift pump, fuel filter, fuel lines, and modifying the fuel tank or acquiring an aftermarket fuel tank.

7. Install the Wiring Harness: Connect the Cummins engine's wiring harness to the Land Cruiser's electrical system. Ensure that all connections are secure and properly routed. This step may require some custom wiring and integration with the Land Cruiser's existing electrical components.

8. Modify the Exhaust System: Modify or replace the Land Cruiser's exhaust system to accommodate the Cummins engine. This typically involves fabricating or purchasing a custom exhaust manifold, downpipe, and connecting it to the existing exhaust system.

9. Connect Drivetrain Components: Connect the Cummins engine to the Land Cruiser's transmission using the adapter plate. Ensure that the connection is properly aligned and the bolts are tightened to the manufacturer's specifications.

10. Test and Finalize: Double-check all connections, fluids, and components before starting the engine. Once everything is in order, start the engine and listen for any unusual noises or vibrations. Verify that all systems, including the cooling system, fuel system, and electrical system, are functioning properly.

It's important to note that this is a high-level overview, and the specifics of the installation may vary depending on your Land Cruiser's model year and the specific Cummins 6BT engine you're installing. It's recommended to consult the engine and vehicle manufacturer's documentation, as well as seek guidance from experienced mechanics or professionals who have performed similar installations

 

[Dubbinchris]

My son is showing me how to write a business plan with Chat gpt.


Me…..

Hey Chat gpt, explain the process of installing a Cummins 6bt in an 80
Series Landcruiser…….

10 seconds later, Chat gpt’s response……

Installing a Cummins 6BT motor into an 80 series Land Cruiser involves several steps and requires a certain level of mechanical expertise. Here's a general overview of the process:

1. Engine Selection: Start by acquiring a Cummins 6BT engine that is suitable for your Land Cruiser. Ensure that the engine is in good condition and matches the specifications required for your vehicle.

2. Gather Required Parts: Along with the engine, you'll need various components to complete the installation. This typically includes an adapter plate, custom engine mounts, wiring harness, fuel system components, cooling system modifications, and exhaust modifications.

3. Prepare the Land Cruiser: Remove the existing engine and associated components from the Land Cruiser. This may involve disconnecting the battery, draining fluids, removing the radiator, and disconnecting the drivetrain components.

4. Fit the Adapter Plate and Engine Mounts: Install the adapter plate onto the back of the Cummins engine. This plate allows you to connect the engine to the Land Cruiser's transmission. Ensure it is aligned correctly and securely bolted. Fabricate or purchase custom engine mounts that will properly position the engine within the Land Cruiser's engine bay.

5. Modify the Cooling System: Adapt the cooling system to accommodate the Cummins engine. This may involve fabricating custom brackets, modifying the radiator or acquiring an aftermarket radiator, and connecting the necessary hoses and fittings.

6. Modify the Fuel System: Adapt the fuel system to work with the Cummins engine. This usually includes installing a lift pump, fuel filter, fuel lines, and modifying the fuel tank or acquiring an aftermarket fuel tank.

7. Install the Wiring Harness: Connect the Cummins engine's wiring harness to the Land Cruiser's electrical system. Ensure that all connections are secure and properly routed. This step may require some custom wiring and integration with the Land Cruiser's existing electrical components.

8. Modify the Exhaust System: Modify or replace the Land Cruiser's exhaust system to accommodate the Cummins engine. This typically involves fabricating or purchasing a custom exhaust manifold, downpipe, and connecting it to the existing exhaust system.

9. Connect Drivetrain Components: Connect the Cummins engine to the Land Cruiser's transmission using the adapter plate. Ensure that the connection is properly aligned and the bolts are tightened to the manufacturer's specifications.

10. Test and Finalize: Double-check all connections, fluids, and components before starting the engine. Once everything is in order, start the engine and listen for any unusual noises or vibrations. Verify that all systems, including the cooling system, fuel system, and electrical system, are functioning properly.

It's important to note that this is a high-level overview, and the specifics of the installation may vary depending on your Land Cruiser's model year and the specific Cummins 6BT engine you're installing. It's recommended to consult the engine and vehicle manufacturer's documentation, as well as seek guidance from experienced mechanics or professionals who have performed similar installations

That told us basically nothing. Lol

 

[William839]

When you have to write an essay on a book you didn’t read

 

[Major Tom]

I’ve been running the cruiser around town and on the highway, testing it. My rpm’s have been too high for my comfort on the highway. At 65-70 mph, my rpm’s have been at 2200-2300 and that’s with stock 4.10’s, 10% overdrive sumo gear and 35” tires.

I started looking around for new diff gears and kept hitting roadblocks. A few people on the LandCruiser 6bt Cummins Facebook page told me that PDI in Australia sold them.

3.55 Diff Ratio Crown Wheel & Pinion Sets - Pre Order

Boost your Landcruiser with PDI gears. Proven in installations, including a 10.98 sec ¼ mile time. Ideal for manual transmission and performance upgrades.

www.performancedieselintercoolers.com.au

I found their page and ordered the set along with their front/rear bearing set.

 

[Major Tom]

Tye McNatt (Business name - The Mechanic Shop) did the install. The front diff was a direct fit and straight forward. On the rear diff, Tye had a few adjustments to make. PDI recommended using a 100 series rear carrier assembly and swapping in the 80 series side gears as the spline count is different between the 80 and 100 series. In Australia, this is a direct fit, straight forward process as the Aussie trucks had limited slip diff as opposed to the USA open diff’s. We swapped in the whole carrier assembly and found some slack around the 80 side gears. Tye tested a few larger gear oilers he had laying around and determined that the GM 8.5 - 28 spline open side gear oilers fit perfectly.

Tye also had to clearance several areas on the axle housing for the new gear to fit.

I’ve been testing the truck now that the 3.55 swap is complete. I have more range in each gear and at 70 mph I’m running 1800-1900 rpms. The clutch also seems easier to operate as well.


Tye commented that he was impressed with the quality of the gears. All below photos taken by Tye…..

Update: Email from PDI regarding axle oil break-in period.
Hi David

We would change the oil at 500km and prob again at 1000km. I would still give it another few 1000km before pushing it hard, as this is the time when the hard facing is formed. If pushing it hard before then, you most likely will find slivers of metal produced, but the gears will otherwise be fine.


Comparison: 80 series side gear with the toyota and GM gear oilers.

Comparison: size difference between the GM and Toyota gear oilers.

 

[Major Tom]

100 Series rear carrier being setup.

 

[Major Tom]

80 series rear housing clearance for the new gear.

 

[Major Tom]

 

[Major Tom]

Oh yes, PDI also sent me a super cool Aussie beer kozzie.

 

[Will Van]

Looking good! How’s it drive now?!

 

[Major Tom]

Looking good! How’s it drive now?!

This truck will be my daily driver once I have the idle shutter in the motor fixed. I routinely work 3-5 hours away from home so highway usage is important to me. The 3.55 gears made 70 mph very comfortable by dropping the rpm’s down to around 1800-1900. It’s also making first gear easier to start from with more range between shifts. The clutch also seems easier to operate as well.

 

[Redbird]

Very nice! I have a 4bt nv4500 setup and have been in the same boat with the high rpms. Guess i need to start looking for a 100 series carrier. As far as the clearancing was that just done with a grinder im assuming?

 

[Major Tom]

Very nice! I have a 4bt nv4500 setup and have been in the same boat with the high rpms. Guess i need to start looking for a 100 series carrier. As far as the clearancing was that just done with a grinder im assuming?

It was done with some small pneumatic grinders.

 

[Redbird]

Did you have to use the 100 series rear housing also or just the carrier. I'm assuming they go together. I'm already on the hunt for one.