evo462

iTrader: (27)

I was told the older style were more desirable for rebuilds due to the hard parts being a little stronger, but maybe a builder can chime in.

I actually just got my 4L80e back from the builder this week, looking forward to giving it a good thrashing!

I got a 4L80e wiring harness adapter for an A4 engine harness off the classified boards cheap, so I decided to just go ahead and swap out my engine harness as well.

slow67

iTrader: (2)

It depends on who's FMVB. It will likely be needed if you want to use lockup.


The biggest hard part difference, is the early style overdrive roller clutch is stronger. Also late model there are some minor differences, but IMO they don't change the strength. They did change lube flow, and in Jake's opinion, its for the worse (he's seen many more planetary failures in the late model style).

chris718

Converter pressure and lube flow are nearly identical in both units.The major issues are flow paths the oil takes when returning from the cooler to lube circuit.The early units necessary components are all fed off of branches from the mainshaft,that is fed a straight steady supply of oil from the lube pipe into a dam that feeds the orifice in the rotating output shaft.A higher volume of unrestricted oil is available to feed the branches in the circuit ,including the overdrive planet.The late unit forces lube thru the center support where it is subjected to reduced flow and then the oil must travel in 3 directions ,and out between a rotating component or several that disrupts oil flow because of oil taking path of least resistance.As well intermediate clutch oiling is poor because it is fed off of intermediate sprag lube which is severely restricted at the center support casting.The od planet is the part that really takes a beating during heavy loads in overdrive the sun gear is robbed of oil because its feed is not from oil exiting the converter.If the oil to the converter was momenatrily shut off under load ,which it is,the lube circuit wont run dry because the oil supply is still a full converter and the reg valve will soon recover and refill.The sun gear doesnt have that luxury on the late center lube units.

1slow01Z71

iTrader: (36)

For those uneasy about running less bolts, remember there is teh dowel pin on each side coming out of the block. There isnt going to be any torsional load on the bolts, all the bolts are doing is simply holding the bellhousing to the block so the pins stay in. Ive put in a bunch of transmissions with just the bolt on either sides of the pin for total 4 bolts. The 80e cover is a good idea too since it protects the torque converter and will keep from blowing oil over the each should you do blow the rear main seal like many FI guys do from time to time.

evo462

iTrader: (27)

Probably a dumb question...but I didn't get a dust cover when I bought my trans...is this something that can be picked up from a salvage yard or something?

Thanks for the input on "early" vs "later" potential longevity differences.

Vetal

iTrader: (3)

1slow01Z71, what cover do you mean when you talk about protection from blown rear crank seal?
P.S. I also didn't get lower bellhousing cover with my 4L80... Big deal IMO as we have lots of dust here in summer

BlwnLs1GTO

iTrader: (12)

Wow,

I've read Many many claims on here that the early units were much weaker than the newer 99+ units. I've passed up many of these units believing this too! And ultimately went with a TH400 instead.
I'm glad I stumbled across this thread. Thanks for the info.

chris718

Ijust started a major project of new gear ratios and aluminum drum for the 4l80e.Take a peek,still in its infancy but something for me to look forward to when its done.http://www.turbobuick.com/forums/tra...80e-parts.html

JAX04

iTrader: (17)

I hear ya, Their are a couple units floating around here, im gonna scoop one up if these people ever return a phone call! lol

MillsMotorvation

Glad i got the older unit! Great info.