FAQs
What fitting on the transmission is return and what is pressure?
Cooler fitting sizes and locations:
| 4R70W |
Top fitting is return, lower fitting is pressure. Stock fitting size 9/16-18 or 5/16 hard tube.
|
| 4L60/65/70E |
Top fitting is the return, lower fitting is the pressure.
|
| 4L80/85E |
Front fitting is the pressure, rear fitting is the return. Stock fitting size is 9/16-18 5/16 hard tube.
|
What transmission fluid is needed?
Transmission Fluid Type and Capacity using a standard depth pan:
|
Transmission Type |
Fluid Type |
Fluid amount with standard pan |
|
Powerglide |
Full Synthetic Dexron VI |
6-8 QTS |
|
TH350 |
Full Synthetic Dexron VI |
9-10 QTS |
|
TH400 |
Full Synthetic Dexron VI |
9-10 QTS |
|
2004R |
Full Synthetic Dexron VI |
10-11 QTS |
|
700R-4 |
Full Synthetic Dexron VI |
10-11 QTS |
|
4L60E/65E/70E |
Full Synthetic Dexron VI |
10-11 QTS |
|
4L80E/85E |
Full Synthetic Dexron VI |
14 QTS |
|
6L80/90 |
Full Synthetic Dexron VI |
12-13 QTS |
|
8L90 |
Mobil1 Synthetic LV ATF HP |
11 QTS |
|
C4 |
Full Synthetic Dexron VI |
8 QTS |
|
C6 |
Full Synthetic Dexron VI |
10 QTS |
|
AOD |
Full Synthetic Dexron VI |
11 QTS |
|
4R70W |
Full Synthetic Dexron VI |
12 QTS |
|
E4OD |
Full Synthetic Dexron VI |
14-16 QTS |
|
6R80 |
Mercon LV |
13 QTS |
|
727 |
Full Synthetic Dexron VI |
10 QTS |
|
NAG-1 |
ATF+4 |
8-9 QTS |
Will this fit my application?
Very broad question. Depending on the application and the transmission you are trying to swap in, there may be modifications required. For Chevrolet examples, generally speaking if your car originally came with a TH400 then a 4L80E would fit. The bellhousing to body is very similar. However, the 4L80E is longer being an overdrive and it may require modification to the tunnel at the rear of the case due to the location where the main harness comes in on the 4L80E.
What stall converter do I need for my application?
Converter stall speed depends on several factors:
- Engine horsepower/torque
- Tire Size
- Ring Gear
- Vehicle weight
- Cam specs
- What you are doing with the car
Gearstar uses this info to determine if you need a single disk or multi disk lockup converter, and to make sure you have enough converter without adding excessive heat.
My 700R4 is shuttering when it goes into lockup
Gearstar 700R4's and 2004R's use a vacuum lockup switch adjustable from 6" to 22" of vacuum. Turning the screw clockwise makes the trigger point happen sooner as vacuum drops (roughly 6" at max turns in). Turning counterclockwise pushes the trigger point back until a lower vacuum is achieved (roughly 1" at max turns out). If your vehicle surges in and out of lock-up, turn the vacuum switch adjustment screw 2 turns counterclockwise.
How much power can a stock AOD transmission take?
The AOD in stock form can really only handle stock power levels. Before planning any engine mods to an AOD equipped vehicle, you should install our AOD Valve Body Kit. Installation of the Valve Body kit will allow this transmission to perform reliably in a 325 to 350 horsepower application. If your power goals are higher, you should consider an AOD Performance Transmission from our product catalog.
I just installed my new transmission (or converter) and it doesn’t move. What could be wrong?
The most common reason for this is that the converter was not fully seated in the pump, which should have shown itself when there was difficulty turning the converter. Providing you have enough fluid in it, remove one line from the transmission cooler. Start the vehicle and fluid should come spraying out. If this does not happen, you may have broken the pump and will need to remove the transmission and repair. Hopefully, you have not destroyed the converter.
Does the AOD have a removable bell housing?
No, the bell housing for the AOD is integral to the case.
How often should I service my transmission?
The recommendation for the fluid service can vary for different vehicle manufacturers. On average, it is recommended to do it every 15,000 miles or once a year. Bring your vehicle in and let us check for leaks and other issues that may arise.
How can I make my transmission last longer?
To make the transmission last longer, don’t ignore it. Check the transmission fluid level and condition periodically and repair any leaks or problems right away. That way, there won’t be any future damage. The most important thing is to service the transmission on a regular basis. If the vehicle is used for towing, hauling, commercial usage, or in high ambient temperatures, use an auxiliary cooler to help it last longer.
My transmission is leaking, can I drive it?
Another good question that we are asked frequently. It shows the owner of the vehicle doesn't want to risk doing more damage and raising the repair cost. A lot depends on the rate of fluid loss. If it's a small leak, and you are very diligent about keeping the fluid level at the proper level, it's okay to drive it in to get it looked at. It the fluid is pouring out, don't drive it. If you have one of many vehicles not equipped with a dipstick, you can't check it. If the unit exhibits any abnormal operation, then the internal damage is occurring, and a minor leak can result in a major bill if not corrected promptly.
What are the typical causes of oil leaking out of a transmission?
- Too much oil
- Pump halves not flush, causing a cross leak into vent or into drain, causing foaming.
- VB cross leak blowing out into oil, therefore foaming the oil.
- Pump gaskets blown on pressure or suction side.
- Broken torque converter, or too much torque converter clearance.
- Over heated oil, which raises the overall oil level.
4L60E FAQ’s
Does this have a Lock up converter? Yes
Cooler fittings: Top is Return Bottom is Pressure
The 4L60E uses a 13pin main harness for the computer.
Does this fit my LS? Yes and no. This transmission only has 6 bolt holes for the Bell housing and the LS uses 7 also the pilot on the torque converter is a different length. Yes, it can be used but there is a better option for those customers. This transmission is designed for the Small block Chevrolet, Big block Chevrolet customers.
Do you need a computer to run this? If you have a 4L60E in a stock application, then no. If you are upgrading to an Overdrive transmission, then you will need a standalone computer.
Will this fit in my XYZ? We all know how complex this is question can be. If they have a TH350 (3 speed auto) or a TH400 (3 speed auto), or a 700R4 (4 speed auto) then yes.
4L65E FAQ’s
Does this have a Lock up converter? Yes
Cooler fittings: Top return Bottom pressure.
4L65E will come with a 13pin main harness connector.
Why does GM Performance have a 4L70? The GM Performance 4L70E is rated lower on Horsepower and torque then our Level IV 4L65’s. They will use the same wiring harness.
4L65E Perfect for LS SWAP applications making under 650hp.
4L80E FAQ’s
Cooler fittings: Front is pressure Rear is return
Is this a lock up converter? Yes
What is the strongest transmission? The 4L80E is the strongest overdrive transmission that we offer. If a customer has a TH400 (3 speed auto) This has the same gear ratio but offers a 4th gear that is overdrive.
Will this fit my XYZ? This is a very difficult question. Often a customer will have to do some tunnel modifications to get the 4L80E to fit. It may be something simple like opening the tunnel at the firewall but could be more complex like having to notch out a section for the wiring harness to connect. Remember these transmissions were designed for full size truck applications from the factory.
4R70W FAQ’s
Options for both Mechanical and Electronic speedometer.
Cooler fittings: Return top, Pressure bottom
Is this a Lock up converter? Yes, any electronically controlled transmission will have a lockup style torque converter.
I have an early Bronco 4x4 will this work? Yes, this will work, and we will install a Dana 20 transfer case adapter kit when we are building the transmission, so it is ready to bolt on.
What plug type do you use? We build 1998+ wiring and it is a Black Plug for the main harness.