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4l80 transmission

Fon johnson

Fon johnson

04 2500 hd
Messages
2
Reaction score
2
Location
Gallipolis ohio
Does any body know what it will take to put a 4l80 transmission and tcase out of a 98 gmc in to a 2005 chevy 2500hd im a little concerned with the tow houl button the 98 dosint have 1 and the 05 does any suggestions b4 i jump into this
 
The trans will bolt in with the exception of the 12 o clock mounting bolt. Tow/haul mode is just a separate shift table that is switchable. As to the transfer case, that is probably a different story.
 
So will the transfercase out of the 05 work with the transmission out of the 98 i have both and both are push button i bought the 98 it has 15000 original miles but no title the guy passed away and its ashame bc this truck dont have a bubbel in the paint no where i was going to swap moter in all it's the 454 but im more of a 6.0 guy myself so im just going use the transmission i just need to figer out what all is going to couse me problems b4 i start im trying to keep this a 1 day job
 
The 05 transfer case will bolt right up. The 4l80e will also bolt up, but you'll only have 5 bolts instead of 6. You'll have to de-burr the shift shaft's and swap the NSBU's, check the trans cooler fittings, but I believe both have the same threads into the case. Just keep in mind if you need parts you have a 98 as the harness and EPC solenoid changed in 04. The big hurdle will be the torque converter. The 454 converter is WAY to low a stall for the 6.0l, and if your other trans has many miles you do not want to re-use that converter. Also keep in mind to NOT use dex 6 fluid as the seals in the 98 are incompatible with it. If it was mine I would stick with your 05's trans and have it rebuilt. A trans that has sat for a long time most likely has hardened seals in it. Not to mention the 98 will not have the better high energy clutches in it.
 
Fon johnson said:
So will the transfercase out of the 05 work with the transmission out of the 98 i have both and both are push button i bought the 98 it has 15000 original miles but no title the guy passed away and its ashame bc this truck dont have a bubbel in the paint no where i was going to swap moter in all it's the 454 but im more of a 6.0 guy myself so im just going use the transmission i just need to figer out what all is going to couse me problems b4 i start im trying to keep this a 1 day job
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It should bolt right up there where no changes in the 98 and the 05
 
udidwht said:
4L80E trans even from 98 is compatible with DEX VI fluid (backwards compatible with DEX III).
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According to GM it is, but others have done testing showing the older seals are not compatible, and will break down and leak. And I for one do not like the idea of running a thinner fluid. Stick to dex/merc fluid for anything that doesn't have viton seals in it.
 
You been lucky.
The 2 big tranny shops out here said they are doing a lot of older trans from it.
Same in the fleet my buddy runs that has just over 250 older pickups that are low mileage trucks all from the 90’s. He said they started swapping to dex6 and about 6-7 months later the problems stated.

Best to stick with proven fluid- especially on any higher mileage trans.

this is reminiscent of “ethonal/ methanol fuel will be fine in older rigs”....
Now only get sae30r9 has become the standard even though you can talk to GM, Ford, etc and they all say The new fuel is ok.
 
Please say which shops so I don’t use ‘em. Haha
The 2 chev and 1 gmc dealership ls that I worked at, all will notify the person before doing that and give them the option.
After GM started denying re-repair costs from the issues, the dealerships now stock outside supply of dex3 just for this issue.
 
Yeah. They (GM) don’t make money from if anymore because the license to it can only be held for so long.
Same reason they went through the mess of dexcool. What was that, 4 or 5 versions before they settled on one that doesn’t screw things up- haha. And all because they were late to the game and all the other companies got the patents on the different versions of antifreeze before them. Good friend of mine was an engineer at GM when all that mess went down w/dexcool. He said he knew one of the chemical engineers and they basically wouldn’t take no for an answer. They wanted proprietary stuff for the profit, regardless of whats actually best.
 
udidwht said:
I know of several shops in California that won't warranty the trans if anything other than DEX VI is used. GM doesn't even recommend or license DEX III anymore.
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They're patent ran out, thats why. But GM DOES still make Dex 3 fluid. There manual trans/transfer case fluid is dexron 3 to a T. GM will not warranty a manual trans or transfer case if dex vi gets put into one that called for dex 3. And dex 6 is far from a "proven" fluid. Tell that to all the allison owners who lost there seals after 6 months if use, or the owners in cold climates that learned the hard way the dex 6 gels below around -20f. It did make for some nice low milage used parts on the market for awhile until they reformulated it. And I know of several big name trans builders who said it was such a bad fluid they wouldn't even use it to flush a toilet with.
 
Yes and no. Allison Service Tip #1099J states Dexron-VI is restricted to use only in transmissions beginning with serial number 6310670488. This is the only official source I could find. However,

...the S/N breaks for new seals that are DEX6 compatible. They are 6310670488 for Indianapolis and 6320784373 for Baltimore (most Pickups). This is generally aligned with the start of 2007 truck builds. These serial numbers and higher have the new seals.

The main concern surrounding the use with DEX VI in Allison applications is that DEX VI has compatibility issues with some of the seal materials formerly used by Allison. Allison has established serial number cut off’s for use of DEX VI (S/N 6310670488 and up for Indianapolis built transmissions, AND... S/N 6320784373 and up for Baltimore built transmissions used in GM pickups.)

Moot given we're talking specifically the 4L80E trans not an Allison. DEX VI today is not the same as DEX VI from 2005.
 
udidwht said:
Yes and no. Allison Service Tip #1099J states Dexron-VI is restricted to use only in transmissions beginning with serial number 6310670488. This is the only official source I could find. However,

...the S/N breaks for new seals that are DEX6 compatible. They are 6310670488 for Indianapolis and 6320784373 for Baltimore (most Pickups). This is generally aligned with the start of 2007 truck builds. These serial numbers and higher have the new seals.

The main concern surrounding the use with DEX VI in Allison applications is that DEX VI has compatibility issues with some of the seal materials formerly used by Allison. Allison has established serial number cut off’s for use of DEX VI (S/N 6310670488 and up for Indianapolis built transmissions, AND... S/N 6320784373 and up for Baltimore built transmissions used in GM pickups.)

Moot given we're talking specifically the 4L80E trans not an Allison. DEX VI today is not the same as DEX VI from 2005.
Click to expand...
Not when Allison used the same neoprene seals up until 06 that GM used. The S/N breakpoint was when Allison switched over to viton seals so GM's dex vi wouldn't eat the seals.
 
No evidence to suggest DEX VI is harmful to seals. It's been widely used for years with many having no issues.

I think I can help you with this. DEXRON-VI was designed to be fully backward compatible with earlier transmissions including the various materials used. This is the difficult part since transmissions built way back when often used materials that really would not or should not be considered as suitable for use in a modern transmission. Some of those seal materials actually relied on the fact that Group I or even Group II fluids would cause them to swell and therefore remain viable. The other problem with those fluids though was oxidative stability which was not good by today's standards. Hence the arrival of Group IV in the automotive arena followed by an increased use of Group III due to cost issues with PAO. The problem with Group III and Group IV is that they do not swell seals much, if at all, and therefore require more and different seal swell agents than previously used. These days those agents are normally, although not always, Esters (Group V). The use of Esters is ,in part, to allow seal swell to simulate that of earlier fluids without the downside of oxidation instability. That is one of the reasons how fluids such as DEXRON-VI can be made backward compatible. The problem with these newer fluids is that when are about to be introduced the materials engineers test them! That's when they find out that they made bad choices in terms of seal material suitability for use in newer transmissions. Now ask yourself is it better to admit that you screwed up or is it a better option to blame any problem on the new fluid? That's how the story of the newer DEXRON and MERCON type fluids being bad on seal performance has come about. Sorry about the rather long explanation but I thought that a bit of background might help (you might be relieved to know that I actually cut it short). In summary if I were you I would not hesitate to use the DEXRON-VI product that you refer to as long as it is a real one. I would also suggest that you do a drain, fill and then do that again after a few miles, say a couple of thousand.
 
I worked many years helping GM, Honda and Ford engineers correct many problems.

Worked with so many chemical engineers it’s sick.

The engineers test almost nothing- they have schmucks like me do the testing.
 
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