4L80E + np205 == ?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

plumbcut · 01-08-2005, 04:26 AM

getting sick of the problems with my 700r4 and if I cant get em worked out Im going to put some serious thought into running a 4l80e that I have.. its a 2wd model.. do I have to change the output shaft or just remove to tailshaft housing? Would a np205 from a th400 bolt up to it?

I realize I would need a trans controller and have to mod driveshafts and whatnot.. not really concerned about that.. its just getting the tranny to mate with the case that Id like to research.. anyone????

pc

784X4GUY · 01-08-2005, 11:21 AM

Yeah buddy that's what Id do if it was possible. Those 4L80-E's are super tough, ive got one in my HD. Good luck with it...Later Mike

1969 GMC · 01-09-2005, 04:47 AM

just get a factory married 4l80e/NP205...'91 V3500 models were the only trucks that could have this combo, and I believe it was an option over the TH400/205, so needless to say its pretty rare. just throwin that out there for ya...

**special-K** · 01-09-2005, 10:03 AM

Talk to Advanced Adapters about that.Another thing to consider is finding the 4L80E/NP241 set-up.That was common(is)and I have heard that is the best alternative case to a 205.

Russell · 01-09-2005, 01:10 PM

I'm planning on running a 2wd 4l80e (due to how common they are) mated to a divorced 205 transfer case from an older Dodge truck. A lot cheaper than trying to rig up a married 4l80e/205 setup

plumbcut · 01-09-2005, 02:28 PM

well I know about the factory setup but its not really an option for me- as I already have the trans and t-case that Im going to use.... running a 241 is out of the question also....

now what I AM willing to do- is find a t-case adapter that will work.. Ive heard that the th400/np205 adapter can be slightly modified to work.. And I will also swap input shafts on the t-case.

I would really like to stay away from AA stuff because its too damn expensive.. Ive researched this a fair bit and have found at least 2 custom adapters (non-AA) on the net that people have used to mate np205 to 4l80e.

regarding the th400/np205 adapter- as best as I can tell, you just need to machine the adapter to accept an O-ring.. if its that simple, I'll go that route.. What Im having trouble finding out is whether or not there is a difference between stock 4l80e output shafts 2wd vs. 4wd.... or would I just be removing the tailshaft housing.

well my search continues

I do have access to a th400/np205 of a buddy of mines, thats just sitting in his garage.. I know he wont part with it but I could get it just for testing/mock-up.

thanks

pc

Russell · 01-09-2005, 04:14 PM

I do believe the output shafts are different...

**Richard** · 01-10-2005, 05:48 AM

This is what I was told about this swap. I have all the parts except the tranny at this point. You need a TH400 NP205 and adapter. You can swap out the input gear and bearing of your 205 if you have the male TH350 style. The case will have to be machined as the bearing is larger. A local machine shop did mine for $40. The TH400 index ring needs a few thousanths machined off to fit the tranny, the bolt pattern is the same. You need to use a 2WD 4L80E the length of the tailshaft does not matter as it will not be used. The output shaft needs to be changed to a version that came in large motorhomes. The reason is that the shaft is fully splined and needs to be cut to length. I have the GM part number and cut length somewhere. I also have an extra TH400 adapter that is already machined to fit the 4L80E (dont ask how I ended up with two) . Let me know if I can help anymore.

*gn4u2c* · 01-10-2005, 11:54 AM

hmm Just have the 700 built the right way.. I have 50k on my rebuilt one. lugging a 4x4 long bed 3/4 ton truck with 3/8 channel bumpers, winch tool boxes, tow trailers all the time. Oh and a 4' lift + spinning 35s for the heck of it I put it on a dyno as a friends car club rented one for the day and at 1pm they had all run there cars so free time 319 hp and 384lbs at the wheels nothing crazy but it gets the job done.

Bill W · 01-10-2005, 05:11 PM

I agree with the last post. I've got a 91 suburban with 186,000 on it with original tranny (700R4) 4x4. No problems and no reason it won't see 200,000.

Bill

plumbcut · 01-10-2005, 11:06 PM

richard- thanks a ton for this info! I'll PM you soon..

please guys dont get me started on the 700r4. its from bowtie overdrives and I have over $2K into the trans alone. It has been into the shop at least 4 times now and going in again. Every time in for something different... I spent money on it so I wouldnt have these problems. I have driven the truck less than 2000 miles in about 2 years because of this transmission.

pc

**special-K** · 01-11-2005, 07:40 AM

You got a bad build?

*gn4u2c* · 01-11-2005, 04:10 PM

yeah they are screwing you over thats the bottom line.

I can find you a local core build it to last and ship it to you for 1,200

no idea why they would want 2K?? you can't buy enuff parts for it to get close to that total.

plumbcut · 01-11-2005, 09:14 PM

okay the bare trans is about 1200 or so if i remember correctly.. throw in a 2200 heavy duty converter, their tv-made-ez kit, braided AN cooler lines, an advance adapters 700r4->np205 output shaft, shift linkage kit, etc etc it adds up quick.

I dont necessarily blame bowtie overdrives. but at the same time, i sort of do. Ill let you know how my next visit w/ them goes. I may be able to straighten this all out yet.

pc

**special-K** · 01-11-2005, 09:56 PM

Don`t get me wrong,I have a 4L80E in my`91 3/4t 4wd Sub(35"rubber)and I love it.It seems bullet-proof.I`m interested in using one in one of my`72s.Do you know the vintage of your 700R4?I know these transmissions went through many upgrades/improvements through it`s years of use.Mostly in the valving,adding more circuits,which helped it alot.I`m just curious.

plumbcut · 01-11-2005, 10:17 PM

its either a '90 or '91.. im pretty sure its a '91

pc

**Richard** · 01-12-2005, 02:15 AM

My brother got a 700R4 from Bowtie OD for his FI small block jeep. If I remember right it was over 2K for the core, build, adapters and install. It shifted way to hard, dont know about longevity as he sold the jeep. Was not to impressed with the outfit and their work on the jeep. On the test drive the speedo did not work because it was not hooked up. The exhaust that they modified fell off in a week of highway driving. They notched the transfercase crossmember/skidplate and did not reinforce it. There are many benefeits to the 4L80E as opposed to the 700R4 swap in a 4x4 IMHO.
Overall strength, it is just a beefier transmission. The tranny output shaft goes directly into the transfer case eliminating the coupler sleeve. I have personally stripped out a 10 spline when I had the SM465 and also mangled the 32 spline coupler with the TH350 setup I swapped it out to.
The step between 2nd and 3rd is more evenly spaced. Granted the 700R has a lower 1st, this is easily overcome with lower diff gears. With large tires and the increased weight and rolling resistance I believe the 2nd 3rd jump is just to much.
The abilty to change shift points and firmness in the fly. With aftermarket shift controllers and or custom software you can change line pressure and shift rpm. I have a controller for my 4L60E in my other Chev and they work great.
The transfer case will move back about 5". This will improve front driveline angles in lifted trucks. The rear is not a problem.
On the downside the swap is more expensive but most things that are better usually are.
IMO the 700r is ok but in my situation the 4L suits me better.

4x4Bowhunter · 01-13-2005, 11:00 PM

more information re: this topic on this thread as well:
http://67-72chevytrucks.com/vboard/s....php3?t=128495

01-08-2005, 04:26 AM	#1
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	4L80E + np205 == ?? getting sick of the problems with my 700r4 and if I cant get em worked out Im going to put some serious thought into running a 4l80e that I have.. its a 2wd model.. do I have to change the output shaft or just remove to tailshaft housing? Would a np205 from a th400 bolt up to it? I realize I would need a trans controller and have to mod driveshafts and whatnot.. not really concerned about that.. its just getting the tranny to mate with the case that Id like to research.. anyone???? pc

01-08-2005, 11:21 AM	#2
784X4GUY Did someone say MUD? Join Date: Aug 2003 Location: Pullman,WA Posts: 1,089	Yeah buddy that's what Id do if it was possible. Those 4L80-E's are super tough, ive got one in my HD. Good luck with it...Later Mike __________________ Im in the market guys...so keep ya eyes peeled -------------------- Mini trucks are for guys who cant get it up!

01-09-2005, 04:47 AM	#3
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	just get a factory married 4l80e/NP205...'91 V3500 models were the only trucks that could have this combo, and I believe it was an option over the TH400/205, so needless to say its pretty rare. just throwin that out there for ya... __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

01-09-2005, 10:03 AM	#4
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Talk to Advanced Adapters about that.Another thing to consider is finding the 4L80E/NP241 set-up.That was common(is)and I have heard that is the best alternative case to a 205. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

01-09-2005, 01:10 PM	#5
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	I'm planning on running a 2wd 4l80e (due to how common they are) mated to a divorced 205 transfer case from an older Dodge truck. A lot cheaper than trying to rig up a married 4l80e/205 setup __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

01-09-2005, 02:28 PM	#6
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	well I know about the factory setup but its not really an option for me- as I already have the trans and t-case that Im going to use.... running a 241 is out of the question also.... now what I AM willing to do- is find a t-case adapter that will work.. Ive heard that the th400/np205 adapter can be slightly modified to work.. And I will also swap input shafts on the t-case. I would really like to stay away from AA stuff because its too damn expensive.. Ive researched this a fair bit and have found at least 2 custom adapters (non-AA) on the net that people have used to mate np205 to 4l80e. regarding the th400/np205 adapter- as best as I can tell, you just need to machine the adapter to accept an O-ring.. if its that simple, I'll go that route.. What Im having trouble finding out is whether or not there is a difference between stock 4l80e output shafts 2wd vs. 4wd.... or would I just be removing the tailshaft housing. well my search continues I do have access to a th400/np205 of a buddy of mines, thats just sitting in his garage.. I know he wont part with it but I could get it just for testing/mock-up. thanks pc

01-09-2005, 04:14 PM	#7
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	I do believe the output shafts are different... __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

01-10-2005, 05:48 AM	#8
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,716	This is what I was told about this swap. I have all the parts except the tranny at this point. You need a TH400 NP205 and adapter. You can swap out the input gear and bearing of your 205 if you have the male TH350 style. The case will have to be machined as the bearing is larger. A local machine shop did mine for $40. The TH400 index ring needs a few thousanths machined off to fit the tranny, the bolt pattern is the same. You need to use a 2WD 4L80E the length of the tailshaft does not matter as it will not be used. The output shaft needs to be changed to a version that came in large motorhomes. The reason is that the shaft is fully splined and needs to be cut to length. I have the GM part number and cut length somewhere. I also have an extra TH400 adapter that is already machined to fit the 4L80E (dont ask how I ended up with two) . Let me know if I can help anymore. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

01-10-2005, 11:54 AM	#9
gn4u2c Account Suspended Join Date: Mar 2003 Location: southern pa Posts: 698	hmm Just have the 700 built the right way.. I have 50k on my rebuilt one. lugging a 4x4 long bed 3/4 ton truck with 3/8 channel bumpers, winch tool boxes, tow trailers all the time. Oh and a 4' lift + spinning 35s for the heck of it I put it on a dyno as a friends car club rented one for the day and at 1pm they had all run there cars so free time 319 hp and 384lbs at the wheels nothing crazy but it gets the job done.

01-10-2005, 05:11 PM	#10
Bill W Registered User Join Date: Mar 2003 Location: Oregon Posts: 229	I agree with the last post. I've got a 91 suburban with 186,000 on it with original tranny (700R4) 4x4. No problems and no reason it won't see 200,000. Bill

01-10-2005, 11:06 PM	#11
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	richard- thanks a ton for this info! I'll PM you soon.. please guys dont get me started on the 700r4. its from bowtie overdrives and I have over $2K into the trans alone. It has been into the shop at least 4 times now and going in again. Every time in for something different... I spent money on it so I wouldnt have these problems. I have driven the truck less than 2000 miles in about 2 years because of this transmission. pc

01-11-2005, 07:40 AM	#12
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	You got a bad build? __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

01-11-2005, 04:10 PM	#13
gn4u2c Account Suspended Join Date: Mar 2003 Location: southern pa Posts: 698	yeah they are screwing you over thats the bottom line. I can find you a local core build it to last and ship it to you for 1,200 no idea why they would want 2K?? you can't buy enuff parts for it to get close to that total.

01-11-2005, 09:14 PM	#14
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	okay the bare trans is about 1200 or so if i remember correctly.. throw in a 2200 heavy duty converter, their tv-made-ez kit, braided AN cooler lines, an advance adapters 700r4->np205 output shaft, shift linkage kit, etc etc it adds up quick. I dont necessarily blame bowtie overdrives. but at the same time, i sort of do. Ill let you know how my next visit w/ them goes. I may be able to straighten this all out yet. pc

01-11-2005, 09:56 PM	#15
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Don`t get me wrong,I have a 4L80E in my`91 3/4t 4wd Sub(35"rubber)and I love it.It seems bullet-proof.I`m interested in using one in one of my`72s.Do you know the vintage of your 700R4?I know these transmissions went through many upgrades/improvements through it`s years of use.Mostly in the valving,adding more circuits,which helped it alot.I`m just curious. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~



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01-11-2005, 10:17 PM	#16
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	its either a '90 or '91.. im pretty sure its a '91 pc

01-12-2005, 02:15 AM	#17
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,716	My brother got a 700R4 from Bowtie OD for his FI small block jeep. If I remember right it was over 2K for the core, build, adapters and install. It shifted way to hard, dont know about longevity as he sold the jeep. Was not to impressed with the outfit and their work on the jeep. On the test drive the speedo did not work because it was not hooked up. The exhaust that they modified fell off in a week of highway driving. They notched the transfercase crossmember/skidplate and did not reinforce it. There are many benefeits to the 4L80E as opposed to the 700R4 swap in a 4x4 IMHO. Overall strength, it is just a beefier transmission. The tranny output shaft goes directly into the transfer case eliminating the coupler sleeve. I have personally stripped out a 10 spline when I had the SM465 and also mangled the 32 spline coupler with the TH350 setup I swapped it out to. The step between 2nd and 3rd is more evenly spaced. Granted the 700R has a lower 1st, this is easily overcome with lower diff gears. With large tires and the increased weight and rolling resistance I believe the 2nd 3rd jump is just to much. The abilty to change shift points and firmness in the fly. With aftermarket shift controllers and or custom software you can change line pressure and shift rpm. I have a controller for my 4L60E in my other Chev and they work great. The transfer case will move back about 5". This will improve front driveline angles in lifted trucks. The rear is not a problem. On the downside the swap is more expensive but most things that are better usually are. IMO the 700r is ok but in my situation the 4L suits me better. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

01-13-2005, 11:00 PM	#18
4x4Bowhunter Registered User Join Date: Jan 2005 Location: Denver, CO Posts: 110	more information re: this topic on this thread as well: http://67-72chevytrucks.com/vboard/s....php3?t=128495

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