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The spacer is only needed to bolt an LT-style 4L60E to an LS engine.
All pre-98' are LT style but some later years from non-LS engines are also LT-style.
LT style have a 298mm input shaft. LT converters have a shorter pilot.
LS style have a 300mm input shaft. LS converters have a longer pilot.
LS style have a slightly deeper bell housing and have a bolt hole in the 12 O'Clock position.
Most LS engines have a shorter crank that LT or SBC/BBC engines; hence the spacer is needed to properly engage the short LT converter's pilot into something solid. Alternatively a pilot extender can be used to engage into the crank.
An exception are some '99-'00 6.0L truck engines have a long crank LS-engine and came with the 4L80E trans. They would not need a spacer, but conversely will not directly bolt to an LS-style 4L60E. If really needed, the converter sponsors can make custom converters to solve incompatibility problems.
i have a non ls style 4L60e that I mated to an LQ9. Before mating it, I changed the bell housing because it didn't have the bolt in the 12 o'clock position. I also used a LS style flex plate. I put the engine into my car and it seems as if the torque converter ( LS style torque converter) is not engaging the transmission at all because every gear seems like neutral, except park of course. There's no grinding or anything. I'm thinking that since the shaft was a 298mm shaft, when I tightened the torque converter to the flywheel, it pulled the torque converter off of the shaft too much since the LS style trannys have a 300 mm shaft. Does this sound reasonable? I need to take the tranny back out but I'm trying to see how to correct this without replacing any major parts. Please provide any input you may have and thanks in advance!!!
i have a non ls style 4L60e that I mated to an LQ9. Before mating it, I changed the bell housing because it didn't have the bolt in the 12 o'clock position. I also used a LS style flex plate. I put the engine into my car and it seems as if the torque converter ( LS style torque converter) is not engaging the transmission at all because every gear seems like neutral, except park of course. There's no grinding or anything. I'm thinking that since the shaft was a 298mm shaft, when I tightened the torque converter to the flywheel, it pulled the torque converter off of the shaft too much since the LS style trannys have a 300 mm shaft. Does this sound reasonable? I need to take the tranny back out but I'm trying to see how to correct this without replacing any major parts. Please provide any input you may have and thanks in advance!!!
You need to replace the LS bellhousing with the appropriate LT one and try again. The LS bellhousing is deeper causing your engagement issues.
Wow, good catch. I totally missed he said he switched bellhousings.
The older style bell housing is missing the top bolt and the LQ9 doesn't have a bolt hole in the 2 o'clock position, so I would be missing 2 bolts. I also I have a stall converter for an LS style transmission. Is there any spacers that would work? I paid $800 for the stall converter so I really don't want to replace it. I thought the LT style trannies were 1 piece without the detachable bellhousing.
The later LT transmissions had removable bells. The LT style bellhousing does have these bolt issues, but it works, and lots of people run them this way. Unfortunately the LS converter will not work with the LT transmission for a variety of reasons. Lockup o-ring location, spline locations, height etc. If you're running the LT transmission, you need an LT torque converter. If you're running an LS transmission, you need an LS torque converter. I vote buy an LS transmission and you would get all the bolt holes, and your converter would fit. Just my .02
The later LT transmissions had removable bells. The LT style bellhousing does have these bolt issues, but it works, and lots of people run them this way. Unfortunately the LS converter will not work with the LT transmission for a variety of reasons. Lockup o-ring location, spline locations, height etc. If you're running the LT transmission, you need an LT torque converter. If you're running an LS transmission, you need an LS torque converter. I vote buy an LS transmission and you would get all the bolt holes, and your converter would fit. Just my .02
-Brian
I was told that this transmission was an earlier style LS, is there a way that I can tell the difference? I was told it came from a 99 Surburban.
99 suburban would be the vortec 350 motor and the LT trans. They changed to the 4.8/5.3 style motor in 2000 with the appropriate LS trans. The first transmission below is an LT style. Note the bellhousing, input shaft and stator support height differences when compared to the LS style below.
I have a PTC bolt together Converter with the 11.5" and 10.75" PCDbolt pattern that is spaced evenly 60 degrees apart, the TCI 399753 Flexplate has the 10.75" pattern but has a 11.066" pattern on the other set. Does someone make a dual pattern Flexplate that will allow me to run all 6 bolts?
There's a few options on the market that have the 11.5" and 10.75" patterns on the same flexplate, but as far as I know, none of them are designed to run both patterns at the same time. That said, I'm not sure what your power level is, but from what I have seen, 3 10mm bolts is usually good to the 8-900whp range, and 3 7/16" bolts can hold 1200+whp. This is assuming a grade 10.9 or grade 8 style bolt.
are you using the gm spacer behind the flexplate?
what year 6.0 L?
flexplate bolted on backwards?
i did a 6.2L (2010) I used a gm flexplate from a 6.0L truck with factory spacer mated to th350 (from a 78 monte) no prob. had to oval out holes for converter though.
ok so I have a 6.0 with a dished flex plate. I'm mating to a th350 and used a .400 longer bushing in the back of crank but while I went under to put in torque converter bolts it was extremely tight and tabs on converter were damn near .5 inch away while snout was hitting hard! So I pulled engine back out and removed crank bushing or extender that was .400 long and reset engine. Well now the problem is that converter bolted up the snout is lacking .15 to .200 thousandths or roughly from crank????! WTH.... all the help is much appreciated! Thank you Joe
Pics of your flexplate/crank assembly and pics of your converter would be helpful here.
in the middle of a th400 swap to ls3 using TCI flexplate 399754 had less than desirable starter gear engagement (had more with 6.0L oem fleplate) and had to machine some material off to have the torque converter pulled out from trans the proper amount,
gap prior to bolting to flexplate was .090 specification is min .125 to .187 max took few thousandths materiial off where it mates to crank to gain starter gear engagement at same time.
Regarding the gap between the torque converter and the flexplate mounting tabs, what are the effects/symptoms of having excessive gap (i.e. the converter gets pulled forward to the flexplate when bolted down by more than 0.187in)? For example, what if the spacing were 1/4-3/8"? Would the transmission behave any differently or are you just running the risk of damaging something?
Regarding the gap between the torque converter and the flexplate mounting tabs, what are the effects/symptoms of having excessive gap (i.e. the converter gets pulled forward to the flexplate when bolted down by more than 0.187in)? For example, what if the spacing were 1/4-3/8"? Would the transmission behave any differently or are you just running the risk of damaging something?
excessive gap can pull it out of the oil pump too far causing damaged pump gears
too tight would cause clearance issues when the flexplate flexes or things expand due to heat.
I have a 1985 c10 with a TH350 and I am putting in a 4.8 vortec with what I'm pretty sure is the long crank. From the info in the beginning of this thread i do not think i will need the spacer. My question is can i find a 4L60 or 4L80 flex plate from a junk yard to fit the rest of my application?
I have a 1985 c10 with a TH350 and I am putting in a 4.8 vortec with what I'm pretty sure is the long crank. From the info in the beginning of this thread i do not think i will need the spacer. My question is can i find a 4L60 or 4L80 flex plate from a junk yard to fit the rest of my application?
Hey there just letting you know what I did
I did an LS3 2010 Camaro engine swap into an 1985 G body and used a TH 350 transmission out of a 78 Monte Carlo I went to the junkyard and got a flexplate from a 6.0 L LS with the bolts and it will come with the GM spacer now I had to oval out the holes to fit my TH 350 torque converter but after that I bolted that up to my engine with the spacer and ran it all summer with no issues hope that helps
Do you happen to remember what transmission was behind that 6.0? That may help narrow down my search. If weather holds ill be junk yarding this weekend.
all trucks with 6.0 L had 4L80's behind them.
I made sure when I called the junkyard to say can I get a flexplate off of a 6.0 L that was bolted up to a 4L80 but I've been told that they all were.
The long crank short crank Years I'm not sure of but it's in this thread somewhere.
(4L80 is basically a th400 with O/D)
01-07-2017, 11:10 AM
