Stick with 4L60e or go TH350
Stick with 4L60e or go TH350 Talked to a bunch of different people on this one and I'm still on the fence. I have the factory 4l60e with like a stage 1 or 2 rebuild and it's done pretty well. Reason I'm considering changing is
1. Inconsistent shifts especially 2 to 3 shift
2. Gear ratio drop off
3. TH350 is lighter weight & more efficient (maybe)
My 60ft seems to be good but after that up to around 1/8 mile people have pulled me and 1/8 to 1/4 fairly even or I pull back a bit. Is that because gear ratio in the 4l60e or something else?...
I'm worried that all of the things I think are problems with the 4L60e might not actually be problems enough to make a positive change in ET.
So many theories on this one and I know every setup is a little different...
1. Inconsistent shifts especially 2 to 3 shift
2. Gear ratio drop off
3. TH350 is lighter weight & more efficient (maybe)
My 60ft seems to be good but after that up to around 1/8 mile people have pulled me and 1/8 to 1/4 fairly even or I pull back a bit. Is that because gear ratio in the 4l60e or something else?...
I'm worried that all of the things I think are problems with the 4L60e might not actually be problems enough to make a positive change in ET.
So many theories on this one and I know every setup is a little different...
I made the switch to a rmvb TH 350 with a 8" PTC converter with absolutely no regrets.I lost a little on my 60' but made it up everywhere else.The 4l60e hits a lot harder on the launch but falls off between the 1/2 shift. Also with the rmvb you can control your shift points a lot better and is more fun to drive and the 350 offers a lot more converter choices.,I ran this trans all race season with no problems sometimes racing multiple times on a weekend= lots of runs.One more thing is the TH350 is a hell of a lot cheaper than a 4ll60e although the initial investment is not cheap, crossmember, dipstick, shifter, tach, trans, converter,driveshaft.
Last edited by nj02z; Jan 17, 2017 at 05:03 AM.
TECH Junkie
Joined: Nov 2013
Posts: 3,913
Likes: 366
From: White Bear, Mn
Talked to a bunch of different people on this one and I'm still on the fence. I have the factory 4l60e with like a stage 1 or 2 rebuild and it's done pretty well. Reason I'm considering changing is
1. Inconsistent shifts especially 2 to 3 shift
2. Gear ratio drop off
3. TH350 is lighter weight & more efficient (maybe)
My 60ft seems to be good but after that up to around 1/8 mile people have pulled me and 1/8 to 1/4 fairly even or I pull back a bit. Is that because gear ratio in the 4l60e or something else?...
I'm worried that all of the things I think are problems with the 4L60e might not actually be problems enough to make a positive change in ET.
So many theories on this one and I know every setup is a little different...
1. Inconsistent shifts especially 2 to 3 shift
2. Gear ratio drop off
3. TH350 is lighter weight & more efficient (maybe)
My 60ft seems to be good but after that up to around 1/8 mile people have pulled me and 1/8 to 1/4 fairly even or I pull back a bit. Is that because gear ratio in the 4l60e or something else?...
I'm worried that all of the things I think are problems with the 4L60e might not actually be problems enough to make a positive change in ET.
So many theories on this one and I know every setup is a little different...
The 4l60e has a pretty aggressive first gear so if the only thing you changed was the tranny, you would 60' better with the 4l60e.
Th350 2nd gear 1.52
4l60e 2nd gear 1.62
Also in both the 4l60e and th350 3rd gear is the 1:1 ratio.
What torque converter are you running and how much power are you making?
Thanks for all the info so far.
Cars current converter is a yank ss4000 and it makes 400whp on pump gas tune, 410 on race gas. At some point later this year I'll be adding more power but still N/A
Cars current converter is a yank ss4000 and it makes 400whp on pump gas tune, 410 on race gas. At some point later this year I'll be adding more power but still N/A
Last edited by sillysspeed; Jan 28, 2017 at 09:21 PM.
TECH Junkie
Joined: Nov 2013
Posts: 3,913
Likes: 366
From: White Bear, Mn
I did read you original post wrong. I read it as laying over on the 2-3/back half of the quarter.
The 1-2 in a 4l60e is a pretty big drop off but still don't think it's your problem.
Th350 1st 2.52
4l60e 1st 3.06
The 1-2 in a 4l60e is a pretty big drop off but still don't think it's your problem.
Th350 1st 2.52
4l60e 1st 3.06
Ive have a ton of mixed reviews and thoughts on the gear ratios. Car 60fts in the mid 1.30's now best being a 1.32 so it's getting it done there.
My best time slip is
1.32 60ft
4.10 330ft
6.45 1/8
105.06 mph
8.47 1000ft
10.17 1/4
132.06 mph
Car shifted pretty good on the 2-3 this run.
My best time slip is
1.32 60ft
4.10 330ft
6.45 1/8
105.06 mph
8.47 1000ft
10.17 1/4
132.06 mph
Car shifted pretty good on the 2-3 this run.
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Posts: 453
Likes: 0
If your car's 60' is 1.32, I wouldn't even consider going to a trans with 1960's technology and gearing, which also has no OD or converter lockup. Might be a while till you see 1.3X.
I know what a 1.42 feels like, I bet a 1.32 is a rush!
Al
I know what a 1.42 feels like, I bet a 1.32 is a rush!
Al
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Verdad Gallardo Yes about 400+ .You will definatly lose 60ft but there is far more to gain with the TH350.I am looking at it from a racers perspective .Even though it is "60 technology" you don't see to many race cars running 4l60e.AS a matter of fact most people around here run a glide.My wife still runs a 4L60e,I would like to switch out that trans but she does pretty good with that car and I don't want to mess with it(5 final round in points races and bracket finals qualifier) at a tough track.
10 Second Club
Joined: Aug 2010
Posts: 4,468
Likes: 195
From: Harford Co. Maryland
You can get a 2.75 1st gear in a th350, they do make a lock-up th350, I would think you will be looking at an 8" converter for the strip or 9.5" for street/strip.
Just had my th350 rebuilt as a forward manual competition since I was slipping in 2nd as well as drive.(still not installed completely)
I would like over-drive, but the cost for the build ....plus the swap....at least stage 3 or 4
BUT, your trans may just be getting tired and need the next step up the ladder rebuild ?
Last fluid/filter change ?
How did it look/smell ?
Just had my th350 rebuilt as a forward manual competition since I was slipping in 2nd as well as drive.(still not installed completely)
I would like over-drive, but the cost for the build ....plus the swap....at least stage 3 or 4
BUT, your trans may just be getting tired and need the next step up the ladder rebuild ?
Last fluid/filter change ?
How did it look/smell ?
Staging Lane
Joined: Apr 2013
Posts: 98
Likes: 0
Ive have a ton of mixed reviews and thoughts on the gear ratios. Car 60fts in the mid 1.30's now best being a 1.32 so it's getting it done there.
My best time slip is
1.32 60ft
4.10 330ft
6.45 1/8
105.06 mph
8.47 1000ft
10.17 1/4
132.06 mph
Car shifted pretty good on the 2-3 this run.
My best time slip is
1.32 60ft
4.10 330ft
6.45 1/8
105.06 mph
8.47 1000ft
10.17 1/4
132.06 mph
Car shifted pretty good on the 2-3 this run.
You can get a 2.75 1st gear in a th350, they do make a lock-up th350, I would think you will be looking at an 8" converter for the strip or 9.5" for street/strip.
Just had my th350 rebuilt as a forward manual competition since I was slipping in 2nd as well as drive.(still not installed completely)
I would like over-drive, but the cost for the build ....plus the swap....at least stage 3 or 4
BUT, your trans may just be getting tired and need the next step up the ladder rebuild ?
Last fluid/filter change ?
How did it look/smell ?
Just had my th350 rebuilt as a forward manual competition since I was slipping in 2nd as well as drive.(still not installed completely)
I would like over-drive, but the cost for the build ....plus the swap....at least stage 3 or 4
BUT, your trans may just be getting tired and need the next step up the ladder rebuild ?
Last fluid/filter change ?
How did it look/smell ?
Fluid is good. It's more of inconsistent shift rpm's than the shift itself although the shift does seem slow. I thought about using the 2.84 planet in the 4l60e but I really haven't seen anyone personally speak of any gains.
Rebuilt LS1, home ported 806 heads, 223/227 cam, yank 4k stall, full suspension, 3000lb race weight and a lot of little details of course 
I will say the car has far exceeded my expectations and has responded to mods better than any other car or truck I've had. That being said, I think it can go faster. I'm thinking this trans could be costing me a few tenth's
I will say the car has far exceeded my expectations and has responded to mods better than any other car or truck I've had. That being said, I think it can go faster. I'm thinking this trans could be costing me a few tenth's
The 4 l junkie has that name for a reason. If you went 10.12 with one feel lucky.
Put a good th400 in and never look back IMO. Little heavier unless you spend the $ on the lw internals.... but the strength is worth it. And a good converter with a th400 you will go faster just for the simple sake you shift it when you want not when the trans decides to work.
Put a good th400 in and never look back IMO. Little heavier unless you spend the $ on the lw internals.... but the strength is worth it. And a good converter with a th400 you will go faster just for the simple sake you shift it when you want not when the trans decides to work.
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Joined: Jun 2013
Posts: 513
Likes: 1
From: Moose Jaw SK, Canada
Originally Posted by JL ws-6
The 4 l junkie has that name for a reason. If you went 10.12 with one feel lucky.
Put a good th400 in and never look back IMO. Little heavier unless you spend the $ on the lw internals.... but the strength is worth it. And a good converter with a th400 you will go faster just for the simple sake you shift it when you want not when the trans decides to work.
Put a good th400 in and never look back IMO. Little heavier unless you spend the $ on the lw internals.... but the strength is worth it. And a good converter with a th400 you will go faster just for the simple sake you shift it when you want not when the trans decides to work.