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Hello everyone. First time posting here. I am in the process of swapping a ls engine into my firebird. I got the engine and trany out a while ago but but finally cracked them apart tonight.
I am surprised to find a 300mm shaft on the transmission. I was expecting to have to replace the transmission but now I am curious if I can use this one.
It does look like a 300mm input shaft. I was told that more recent V6 have those.
I would suggest installing the Vette servo and getting the Transgo HD2 or Sonnax Performance Pack shift kit installed soon. Otherwise the shifts will be very soft which also means slippage and wear.
The bell housing and the converter have to match the input shaft.
So, I would say no.
To be sure, confirm that the mounting holes on the converter align with your flexplate.
I am pretty sure it is not 245mm. The 245mm looks a little different.
Also, did they make a 245mm shaft on a 4l60e with a removable bellhousing? Did they make a 245mm shaft for a 3800?
If you look closely at the Input shaft, You will notice it necks down right after the Stator Support Bushing. A 300mm shaft does not neck down. I assure you, If you pulled the Input Drum it would be very apparent.
ALL 3.8L Series II RWD engines with 4L60E's have 245mm Shafts, No exceptions, The only deviation from previous 245mm 700R4/4L60E is they have a V8 clutch count, 553 "V8" 2nd piston, & a "High speed" reaction planet with the 3800 Series II. And of course...In '98 they got the "Modular" Case.
The confusion (guessing) is because in around 2002.....The 4.3L V6 got 300mm 4L60E's where they had the 298mm prior to that.
You can reuse your trans, You will need a 300mm Input Drum, 300mm Stator Support Shaft, Bellhousing, 093 "Vette" 2nd piston, At least a 471" Boost valve & a 300mm converter. Generally easier to start with a 300mm core & build from there. And yes you can use a 300mm Truck transmission!
My 2001 Camaro was a 3800 car, If you have any questions let me know, There are many myths about this swap on the internet....
If you look closely at the Input shaft, You will notice it necks down right after the Stator Support Bushing. A 300mm shaft does not neck down. I assure you, If you pulled the Input Drum it would be very apparent.
ALL 3.8L Series II RWD engines with 4L60E's have 245mm Shafts, No exceptions, The only deviation from previous 245mm 700R4/4L60E is they have a V8 clutch count, 553 "V8" 2nd piston, & a "High speed" reaction planet with the 3800 Series II. And of course...In '98 they got the "Modular" Case.
The confusion (guessing) is because in around 2002.....The 4.3L V6 got 300mm 4L60E's where they had the 298mm prior to that.
You can reuse your trans, You will need a 300mm Input Drum, 300mm Stator Support Shaft, Bellhousing, 093 "Vette" 2nd piston, At least a 471" Boost valve & a 300mm converter. Generally easier to start with a 300mm core & build from there. And yes you can use a 300mm Truck transmission!
My 2001 Camaro was a 3800 car, If you have any questions let me know, There are many myths about this swap on the internet....
Thank you for the information. I truly appreciate it. If I run into any issues with the swap I will reach out to you.
I do not have a Camaro. but check this out. I have a 2004 chevy astro. and my transmission got fucked up, 2 years ago, so I bought a rebuilt one, now my transmission is bad again, so I am rebuilding myself in the process of removing the transmission I found that mine has the 298mn setup(this suppose to be for 4l50e from 93 to 99, so I am in the same situation that you are in, I would love to use the bigger converter that comes in the 300mm but like the other fellow in here said, I will have to change the drum, and other parts to make work, I bought a rebuild transmission that came from a 2003 chevy silverado, but that has the 300mm, setup so I am going to begin the swap and see what will happen. I know this thread is old, but I was looking for information about what I am about to do with my van, and I stumbled on the internet with this info. which is really helpful for me, thanks.
I do not have a Camaro. but check this out. I have a 2004 chevy astro. and my transmission got fucked up, 2 years ago, so I bought a rebuilt one, now my transmission is bad again, so I am rebuilding myself in the process of removing the transmission I found that mine has the 298mn setup(this suppose to be for 4l50e from 93 to 99, so I am in the same situation that you are in, I would love to use the bigger converter that comes in the 300mm but like the other fellow in here said, I will have to change the drum, and other parts to make work, I bought a rebuild transmission that came from a 2003 chevy silverado, but that has the 300mm, setup so I am going to begin the swap and see what will happen. I know this thread is old, but I was looking for information about what I am about to do with my van, and I stumbled on the internet with this info. which is really helpful for me, thanks.
I don't know about the Astro van but GM used a 300mm converter behind the full sized van & trucks with the V-6 starting in 2001 I believe.
The 4L60E transmission started out with the 298mm converter design for large V-6 & V-8's. 245mm for 60 degree V-6 & 4 cyl.They all had 1 piece case from 1993-1997 full sized vehicles. The bolt on bell-housing started in the S/T vehicles in 1996. Full sized trucks started the bolt on bell-housing in 1998. The 300mm bell-housing was a Gen 3 LS design.
The 300mm bell-housing is 5/8" deeper to accommodate the converter size. That makes the overall length longer, which will require driveshaft modification.
My question is; Why do you want the larger converter? It's not any more reliable than a 298mm converter..
FYI, You'll get more traction from creating a new post. Some won't look at old threads...
Last edited by Tranzman; 07-08-2023 at 06:55 PM.
Reason: content
My 1999 Silverado GMT 800 NBS 4.3 had the 300 mm input shaft version. Also had the top LS bellhousing bolt, but obviously no bolt there on the SBC-based 4.3. As far as I know, all of the NBS got that input shaft.
My 1999 Silverado GMT 800 NBS 4.3 had the 300 mm input shaft version. Also had the top LS bellhousing bolt, but obviously no bolt there on the SBC-based 4.3. As far as I know, all of the NBS got that input shaft.
I posted some photos of it here before.
You are correct, I looked at my converter catalog again and they show a 300mm converter 99-up C/K trucks w/4.3L. Maybe it is the vans that retained the regular bell-housing for 2 extra years.
11-08-2015, 05:25 PM
4l60e 300mm shaft on v6? 
