I have a 2000 5.3 regcab and when i get on it and it downshifts the truck takes off and the tach will hit 6k before it shifts but when it gets to 6k it holds for like a second, sounds awful too(engine continuous rev at 6k). Is part of my tranny already wearing out. Need to know if i need to go ahead and save up for that 4l80. Also, i saw in some thread and was wondering what the heck a 4l65 is. Thanks

 

Do you have to let off the gas before it will shift? If so, the engine is probably hitting the rev limiter so it can't reach your wot shift point.

 

Mine did this exact same thing right before it killed 4th.......then 3rd gear completely.

Those cruising in 4th to 2nd gear WOT downshifts are hard on the trans.

It could be a rev limiter thing if you've messed with your computer but, in my case it wasn't. The trans was slipping and wouldn't engage 3rd gear at WOT. This cause the motor to sit on the rev limiter if you kept your foot in it. It would shift to 3rd if I let my foot up enough off the gas.

I killed the 4L60E in my Camaro also doing the cruising in 4th to 2nd gear WOT downshift with the procharger on. Same thing happened, it wouldn't upshift to 3rd gear at WOT and sit on the limiter.

These transmissions suck.

A 4L65E is a beefed up version of the 4L60E that GM puts in the 1500 series trucks with a 6.0L engine.

 

If you dont have the money to do a 4L80 swap then you might wana invest in a shift kit cause the 3rd gear is the weakest part of the 4L60 and a shift kit improves that by 300%

 

I agree. A TransGo kit and a decent set of 3-4 clutches will really help w/ 3rd gear issues.

 

yea check in to the FLP Red clutches i beleive is what they are

 

Let's get a list of your mods and what we're working with. What truck and how many miles more specifically.

I'm gonna say it's a shift point/rev limiter thing if you have a handheld programmer. When it does shift, does it slide into gear or does it hit the gear with a 'normal' amount of pressure?

 

My truck is a bone stock(save a k&n and flowmaster). Its a 5.3 with limited slip(i believe-cuz it leaves 2 pretty black marks once in a while). the truck has 63k on it and when i notice it it is not running in 4th and kicking down into second, im assuming its in second or third cuz usually im doing about 30-35 when i stomp it and it kicks down. the truck does not make any funny noises when its a 6k. it doesnt even seem like its hitting the rev limiter unless its a soft hit limiter(you know a hard one is where you can actually hear the engine popping or revving up and down). it just seems to stay a steady 6k and then when it feels like it shift. its medium to medium-hard when it finally shifts. If i end up needing a new tranny does anyone know anyone who could help me to switch to a 4l80 and also what is the possibility of me changing it to a floor shifter just for looks or even maybe a 6 spd. thanks for the help guys

 

It's a shame to hear that they suck. So GM hasn't beefed them up over the years? The 7r400(?) sucked too didn't it. The TH350 and TH400 were a lot better,right?

 

Actually, these transmission are pretty good when drove in a sensible manner BUT, how many of us here drive like that.

GM has beefed them up over the years and the newest version 4L65E seems to hold up well in the Silverado SS and other apps.

There is still alot of room for improvement though. I think the 4L80E or a totally redesigned smaller 80E power handling capable trans should be in every vehicle over 4000lbs with a V8.

The TH350 and TH400 have grown into great transmissions over the years unfortunately they don't have overdrives which I don't know if I could live without anymore.