Transmission options for 1998 K1500 suburban, need expedition level reliable

[evilfij]

After a cooler line rotted out and dumped the fluid, the trans in my suburban is now slipping, what is the best option to replace? As much as I would like a manual, I already have a new jasper autotrac t-case and I understand I would have to change that so I am probably leaning toward a stock replacement auto but who makes the best? Jasper? GM? How much am I looking at for a replacement installed? Only relevant mods are 265 75R16.

 

[Martinjmpr]

Are you upgrading to a 4L80E? If I was popping for a new trans that's what I'd do. Don't have any recommendations on suppliers since I haven't had to do that yet (crosses fingers and knocks wood!)

 

[lt1fire]

That should be a 460LE in there right?

Find a shop around you that knows transmissions, a race or 4wheel drive oriented shop would be great. Tell them your plans for the truck, if you plan on adding huge tires and lots of power through the engine and get them to build it the way you want it. Even if you are staying stockish upgrading the trans is a good thing.

 

[evilfij]

Is the 4L80E a bolt in replacement?

It is a 4L60E now. When my father bought it in 1999 there was the GM strike and there were no K2500 available so he got the K1500.

I don't know any local transmission shops I trust. I just need the thing to be bullet proof as I plan to take it on a very long trip some day (Alaska). No extra power and only +1in on the tires.

 

[Martinjmpr]

Is the 4L80E a bolt in replacement?

It is a 4L60E now. When my father bought it in 1999 there was the GM strike and there were no K2500 available so he got the K1500.

I don't know any local transmission shops I trust. I just need the thing to be bullet proof as I plan to take it on a very long trip some day (Alaska). No extra power and only +1in on the tires.

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On the GMT-800 trucks the 4L60 to 4L80 swap is not a "bolt in" but it can be done and a lot of people do it. My understanding (I'm getting this 2nd hand so take it for what it's worth) is that if the 4L60 goes out and needs to be replaced, the cost to upgrade to a 4L80 is not that much higher for a much more rugged and reliable transmission. I do believe the T-case has to be moved back and the driveshafts either lengthened/shortened or just replaced with equivalent driveshafts from a 2500 model (since the 4L80 is standard on the 2500.) Again, this is 2nd hand so keep that in mind.
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Pretty sure the GMT-400 2500 series trucks had the 4L80 as well so the parts to do the swap should be out there.
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EDITED TO ADD: I have also heard of people upgrading their 4L60E to 4l65E specs. I think there are a couple of GMT-800 folks here on ExPo who have done that.

 

[evilfij]

I don't think I need to be moving t-cases and driveshafts, but I am very interested in the 4l65E spec upgrade.

 

[rayra]

http://www.hotrod.com/articles/ccrp-0711-4l60e-to-4l65e-gm-transmission-conversion/


There are a few vendors bandied about that sell rebuilt and warrantied 4L65E transmissions for $1500-1900. And brand new 4L65E direct from Chevy is $2500.
The 4L60E seems to be plenty strong and durable, as long as you don't put a race / high horsepower motor in front of it or tow max loads (or heavier). They seem to go far if not regularly abused.


I was gonna say the same thing Martin did, given your circumstances. The 4L60 is dead, long live the 4L80. Junkyards are full of the parts to inexpensively support the swap.

 

[evilfij]

Given my other projects which means time is not plentiful and the unknown of a junkyard 4l80e I took the suggestion of a local shop for a rebuild into consideration. I found a local guy who builds drag racing automatics and am going to try him I think. His price is good and he seemed to know his stuff plus I get to keep the original trans with the truck (319k on it).

This way I can keep the taco and rovers out of the snow this winter.

 

[rayra]

oh certainly the rebuild, I wasn't suggesting a junkyard trans. I'm talking about the driveshafts and any different brackets / mounts. And seals and u-joints are inexpensive, good time to replace those.
Just a suggestion. You entered asking for 'expedition level reliable'. The 4L80 is certainly preferable to the 4L60 and would be a relatively easy and straightforward swap since it's a factory option and common and widely available in your vehicle type.
But really, I expect a purist will come along and suggest a manual transmission, anyway. I wouldn't want an automatic on an 'expedition' myself. Too much **** to go wrong with them, vs a manual. And you can readily pack along a spare clutch plate and the basic tools it takes to change one. 'Expedition'-wise.

 

[evilfij]

I would love an NV4500, but this guy has me convinced that the auto will be strong enough for my uses and will last as long as I keep fluid in it. I mean the stock one was fine at 319k until the line rusted out so here is hoping.

I looked hard at the manual swap (if I am going 4l80e the manual swap is not much harder) but it is time and parts and money and finding someone willing to do it mostly.

My only question now is do I spend the $400 extra to do 4l65e spec parts or not. Trans guy thinks I am nuts for a stock motor truck. I am not doing the Darien gap, I just don't want something that is known suspect (like a cheap reman). Where I would be going Amex will solve all problems.

 

[kojackJKU]

I dropped the trans in my suburban while plowing 2 years ago. Had the transmission rebuilt with a performance shift kit installed. Its been awesome since. I am very careful with the transmission now, and hopfully it will live. I moved he rig the other day with no brakes, I was expecting my emergency brake to work, it never so I had to slam in park, I hope I never did any damage to the trans. I was only going a couple of MPH. I would rebuild and install a B&M shift kit like I did....It is a great upgrade.

 

[cyclic]

Give Monster Transmission a call, 1-800-708-0087 they have what you need/want at a good price. And they will make sure you get the correct version for your truck. They are out of Florida and ship everywhere.

 

[justcuz]

I'm surprised the drag strip trans builder did not at least suggest a shift kit, better sun gear shell and Corvette servo bare minimum.
But, like you say the original lasted 319,00 miles.
Sounds like a reasonably knowledgable, honest guy.

 

[RedF]

If the original lasted that long, a mildly upgraded unit with a nice big cooler should last longer than the rest of the vehicle.

 

[Tiki]

I've read enough 4L60E rebuild stories that I would choose 1) GM remanufactured or 2) 4L80e swap