96 Suburban 4x4 Transmission Troubles

I have a 96 Chevy Suburban 4WD that has over 200k miles. At about 90K the transmission went out and was fixed under warranty. At about 180k the transmission went out again and was rebuilt. Reverse recently came out of
the vehicle and the transmission again needs work. The vehicle otherwise is in great shape inside and out including the engine. I have been told there were two different transmissions for this vehicle. The one i have apparently has given trouble from the start. If i have the current transmission rebuilt should i expect it to go out again in about 90k miles? Of the two that came in this vehicle is one better, more longer lasting than the other? If so how do I go about getting the right transmission? Any help or advice would be appreciated.
Thanks.
Ed
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One transmission came in 1/2 ton versions (4L60E), the other in 3/4 ton versions (4L80E). It's not like there were two different versions for a K1500 Suburban. The 4L80E is rated for greater power/torque input and towing. I've owned a new 94 K1500 (4L60E) Suburban that the planetaries for 1st and OD went out (apparently a relatively common issue when trouble happens)on at about 120,000miles. Did a rebuild on the original at the GM dealer and it was flawless and still going strong with the second owner who tows with it and is now at 230,000 miles with no issues. Who is doing the rebuilds and what exactly are they doing when they do it? There are rebuilds and there are rebuilds.
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wrote:

The 4L60 is a electronically controlled version of the 700R4 which was kinda based off of the THM 350 design with different gear ratios and the 4L80 is basically a THM 400 (same gear ratios) with OD added to it. One of the weaknesses of a 700R4/4L60 is heat. I have a 89 V1500 4x4 burb that has a factory HD towing package and came with a aux external engine oil cooler and a HD cooler for tranny in radiator but not a aux exteranl one. I installed a small aux exteranl one shortly after I bought it and it has been trouble free to this day after more than 180K miles and over a dozen cross country trips. It has also had tranny fluid and filter changes about every 25K or two years which ever comes first. Typically, these unit tend to fail sooner in big heavy vehicle with big tires of tall gears which places more strain on tranny in the form of most time spent on torque converter stall (which makes a lot of heat) and more frequent down shifts too. Sone burbs can come with a 3.42 (GU6) which causes tranny to labor more, run warmer and down shift a lot. Do install a aux tranny cooler in series with factor tank cooler (route it through tank then aux cooler) as it is cheap insurance. No need to get carried away on the size of it though. ----------------- TheSnoMan.com
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Tranny went out on my 90 Blazer, had a local guy rebuilt it, with a 1 yr guarantee. Tranny goes out like 1 yr and a week later. Tranny guy did a complete rebuild for free! This time he used a different case. He told me that some cases will go "bad". Not sure how or why a case goes bad, but the new rebuild has been going strong for several years, and I tow a boat everywhere I go.
Really, on a working truck, 90K aint that bad for a tranny rebuild. Ive been through several trannies over the years. Im hard on my trucks....and trannies dont last forever. Just get it rebuilt and go. Talk to your trans expert about the case and see what he knows...
Also, if you do any towing on a OD tranny, use D, this will lengthen the life expectancy.

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