: Transmission Durability?



samm
04-18-06, 09:35 AM
hey if mike is out there somewhere it would be great to hear from him too but do you guys think the stock tranny would hold up to a turbo/super charger? or do you think an aftermarket one would be the way to go?
any thoughts are welcome.
oh, and mike, what tranny are you using and how well is it holding up? thanks guys,
SAM

danbuc
04-18-06, 04:49 PM
The 4T80E is a strong tranny when used in conjunction with an engine that does not exceed it's specififed maximum torque input. Throwing a Turbocharger or Supercharger on the engine will stress the tranny, and could cause severe damage. The clutch packs that are used were not designed to handle excessive load for very long. For example, the N* puts out either 295 or 300lb/ft of torque depending on engine model. Increasing this output to say 400lb/ft mean that th clutch packs are now trying to work against 100lb/ft of torque over what they were designed to handle safely. Shifting an engine with this much power at WOT is likely to cause the clutch packs to slip and burn, simply because they do not have the required clamping force to overcome the added torque.

You can get a performance rebuild done using heavy duty friction and steel plates which are better suited for the higher loads. The heavy duty friction and steel plates used in a performance rebuild apply more clamping force, which in turn can hodl the gearsets better than the stock clutchpacks, keeping them from slipping under heavy loads.

Even this isn't bulletproof. It's not just the clutch packs you have to be worried about. They're also the pinion gears in the diff, the axle shafts,..ect which are all susceptible to breaking when overstressed by excessive power levels.

The real question is, How much power are you looking to produce. Depending on what you want to do, you can modify the drivetrain accordingly to suit your particlular needs. One apllication may only require stronger clutch packs, while another might benefit form an LSD.

samm
04-18-06, 11:40 PM
thanks for the help!
Whats an LSD though?

cart69
04-19-06, 12:12 AM
Limited Slip Differential, a posi unit, also you can buy different torque converters and all for the 4t80 i have heard so you should be able to beef it up any way you please Mark99sts is running a turbo on his with a beefed up trans do a search for his posts to see more

samm
04-19-06, 12:35 AM
lol, i meant mark in my first post, not mike.
thanks

danbuc
04-19-06, 01:51 PM
Limited Slip Differential, a posi unit, also you can buy different torque converters and all for the 4t80 i have heard so you should be able to beef it up any way you please Mark99sts is running a turbo on his with a beefed up trans do a search for his posts to see more

Mark's tranny is completely stock except for the converter and LSD. That's why he's hesitant to let the tranny shift at WOT for fear of grenading it. When his goes, he's going to build a heavy duty one that can handle the power he's producing. Right now, if he let's it shift at WOT, there's a good chance it'll break, and most likely in a loud, and messy way.

MARK99STS
04-21-06, 07:09 PM
I'm still running. Just been very busy lately. One thing Danbuc forgot to mention is that I am running an external trans cooler. I think that will add to the life of the tranny more than anything else. Heat is its worst enemy.

danbuc
04-22-06, 03:38 PM
Damn, forgot about that. Good to see she's still holding up alright.

samm
04-25-06, 12:20 AM
thanks for the input guys. but damn this could get spendy. there wouldn't be a market for 4.6L N* supercharger kits would there?