djfcars,,,
I hate to say it, but the TH350 was a much stronger transmission in general... It being a 3 speed, and always revving well, had no low fluid pressure problems that plagued it... It was a pretty strong transmission overall... If you kept it clean, and didn't overheat it, it lasted a good while... I had one in a 1978 Monte with a 305 that I ran hard (2nd car in my life) ... That tranny out lived the 305 that went 187,000 miles!
Ever since the advent of the Overdrive transmission, oem's have had fits with adequate fluid pressure in OD to keep critical parts cool ... The best thing I can tell all of you, regardless of what your manual says, follow the following guidelines:
- Don't run in Overdrive until you are over 50 MPH, or better yet, run in Tow/Haul in stop and go driving ...
-Don't pull ANYTHING or haul people around unless you are in Tow/Haul period...
- Tow/Haul always will be better for the transmission's longevity...
I feel I need to explain ... Shifting quick reduces clutch pack abrasion which reduces clutch material getting in the fluid, and reduced abrasion or slippage reduces overall heat production... Running the engine at higher RPM's also runs the transmission's overall fluid pressure higher, and flows it faster, meaning better heat dispersion, and cooling capacity...
*** If you are regularly allowing your transmission to run lower than 1500-1600 RPM in Overdrive, you are causing above normal wear... Sorry...
In a 3500# Camaro this is not as bad, but in a 6,000 # truck that can pull 8,000#'s
It's abuse folks... Get that tach up there, and let that tranny run cooler...
Those of us with the weak kneed 4L60E need to pay particular attention to this ... It makes no sense why GM offers a strengthened version of the 4L60E called the 4L65E (to add) ... Maybe the fact that the 4L60E is rated at a max RPM of 6100, and the 4L65E is only 5600 RPM ... Maybe they figure the 5.3 is going to spool a little faster than the 6.0 ... Who knows ... I really shouldn't say weak kneed, as the 4L60E isn't a bad tranny... Especially since 1998... The only real problem I think GM hasn't addressed fully is the pressure regulator boost valve/sleeve assembly... Now, we could compare the 4L60E to the Ford 4R70W or E40D which is a little better than the 4R70W... Or the even worse the Dodge 518 and 618's ... These trucks are highly "overrated" ... I wouldn't own an automatic Dodge period ...
As far as the other inherent "weaknesses" of the 4L60E (or electronic 700R4) the only thing we can do as owners, is keep the fluid / filter cleaned... MAX 30,000 miles on a pan/filter dump, and 50,000 on a full flush ... Make sure you get the proper filter also, the 4L60E has two pans... A deep sump, and a standard sump... I'm pretty sure all 1500 av's have the deep sump... Just reference your owner's manual before picking one up... I know from about '99 to '01, filter kits were dealer only... This has changed, just be aware, some parts house computers may not be up to date... Best thing is to match your new filter up to the oem version just to make sure...
GM has made a few design changes to keep the fluid flowing and cooling better... A MUCH bigger 300mm torque converter that holds lots-o-fluid, a deeper sump pan, and an indestructable torque converter clutch that allows slippage under throttle, and before full lock-up, again to try and maintain adequate fluid flow...
Finally,,,
The trucks of today must meet CAFE fuel mileage averages... The shift patterns in regular DRIVE or the OVERDRIVE setting are set to acheive maximum fuel mileage results... NOT transmission longevity... Loafing around at 1300 RPM in overdrive in a 6,000 # truck is foolish, and don't let me catch you on a meet ... LOL
11H