GMC W4500 Forward Transmission Problems & Cost | 4L80E

The GMC W4500 Forward was equipped with the 4L80E transmission. But they aren’t without their problems though, so let’s look at some of the most common GMC W4500 Forward transmission problems, look at cost estimates and figure out what you can do about them.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

GMC W4500 Forward Transmission Models

GMC W4500 Forward: 4L80E Transmission

GMC W4500 Forward Transmission Replacement Cost Estimate

Pricing varies by model. To be 100% sure on pricing, have your VIN# handy and use our Get An Estimate feature to look up your transmission by VIN#.

Replacement GMC W4500 Forward Transmission Prices:

What are the DTC codes related to GMC W4500 Forward transmission problems?

GMC W4500 Forward Transmission Recalls

None Found

GMC W4500 Forward Technical Service Bulletins (TSB)

TSB 08-07-30-001 – 4L80E Transmission
Problem – Harsh or delayed shifts, slipping, no forward/reverse gears. Possible DTCs: P0741, P0742, P0751, P0752, P0756, P0757, P0894.
Solution – Rebuild or replace the valve body.

TSB 08-07-30-015 – 4L80E Transmission
Problem – Harsh shifts, delayed 2-3 shifts, 2-3 shift flare, no 3rd gear, slips in 3rd gear or reverse. Possible DTC 0757.
Solution – If none of the issues described in Bulletin 08-07-30-001 are present (debris in #11 checkball, leak in oil circuit, damage to the direct clutch), then replace the 2-3 shift solenoid due to a possible sticking pintle.

TSB 08-07-30-016 – Slipping, refusal to shift, overheating – 4L80E Transmission
Problem – Slipping between the gears, overheating, refusal to shift out of a gear, and/or DTC P0894 or P0218, may be because by friction material debonding from the torque convertor clutch (TCC).
Solution – If the friction material has circulated throughout the transmission, the entire transmission may need to be replaced. It is possible to remove the material from the internal components (like transmission cooler lines and the valve body), but it depends on the extent of the damage.

Common Problems with the GMC W4500 Forward Transmission

Lack of Response
Leaking Fluid
Low Fluid
Burning Smell
Grinding or Shaking
Whining, Clunking or Humming
Refuses to Go Into Gear
Torque Converter Issues
Valve Body Issues
Transmission Noisy in Neutral
Gears Slipping
No 3rd or 4th Gear
No 1st or 2nd Gear
No Reverse
Dragging Clutch
Trouble Codes / Check Engine Light

Can I drive with a transmission problem?

If your GMC W4500 Forward can still make it up and down the road, you might say “It’s fine, I’ll just drive it until I can get it fixed”. But that is not always a good idea, depending on the symptoms. You see, there are a lot of (very expensive) moving parts inside of a transmission, and if something isn’t right, continuing to drive with a transmission problem could damage something else.

How often does a GMC W4500 Forward transmission need to be replaced?

The overall lifespan of a GMC W4500 Forward transmission largely depends on how well it was maintained. Factory design flaws also factor into this equation, along with how/how hard you drive. But on average, we’ve seen the GMC W4500 Forward transmission last for between 130,000-180,000 miles. A high quality replacement transmission however, can last considerably longer if all of the factory design flaws have been addressed and the vehicle has been maintained.

How are GMC W4500 Forward transmission issues diagnosed?

It is fairly easy to guesstimate what the root cause of your GMC W4500 Forward transmission problems might be, but you won’t truly know unless you have the right tools and experience. A good mechanic or transmission repair center will be able to connect your truck to a computer and find out which diagnostic trouble codes (DTC’s) have been stored. Once they know what to look for, they can perform a visual inspection to verify the problem.

How is a GMC W4500 Forward transmission replaced?

In order to replace your GMC W4500 Forward transmission, the truck has to be lifted from the ground in order to gain access to all of the parts that will need to be unbolted. Then the transmission can be lowered to the ground (typically with a transmission jack), so the new transmission can be installed. Once it is in place, for the 6L80, the vehicle PCM will have to be reprogrammed / reflashed to accept the new transmission using the latest GM subscription.

Recommendations for GMC W4500 Forward transmission issues?

To save time and get back on the road faster, have your 17-digit truck VIN# handy and you can get an online quote for a reman GMC W4500 Forward transmission here, then find a local shop using our Find a Shop guide to install it for you.

How to Solve GMC W4500 Forward Transmission Problems

Solution A: Buy a Used GMC W4500 Forward Transmission

The quickest way to fix your transmission problems is to simply buy a used transmission or used transmission. These can be found at most junk yards, and they often come with a 30-90 day warranty. However, there’s no way to determine the actual condition of the internal components, so you could be spending a bunch of money to have the exact same problems. Plus, that warranty only covers the transmission if it’s defective, not the labor costs that you’ll have to pay.

Solution B: Buy a Rebuilt GMC W4500 Forward Transmission

Another option would be a rebuilt transmission or rebuilt transmission. A local repair shop will remove your transmission, then install a bunch of new parts during the rebuild. The problem here is, the skills and experience of each transmission rebuilder will vary widely from shop to shop, so you could have problems from something that wasn’t adjusted properly. And the 1-2 year warranty might only cover you at certain transmission repair shops, in a specific geographical area.

Solution C: Buy a Remanufactured GMC W4500 Forward Transmission

Many owners depend on their vehicle to commute and get things done. Their gasoline engines are designed to go 100’s of thousands of miles, so it makes sense to invest in a remanufactured transmission.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

What Problem Does Your GMC W4500 Forward Have?

Let us know the year, mileage and problem you’re having as well as any trouble (OBD) codes you’ve found. If you’ve been given a quote or paid for a repair, we’d like to hear about that too!