• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Flywheel fitment issue on a new Optimizer engine.

Goose57

Well-Known Member
Messages
231
Reaction score
574
Location
Eureka Mo.
Hi all finally got my new Optimizer set in my truck. I went ahead and bolted the rebuilt 4L80E trans to it and set it in all by myself. I didn’t install torque converter bolts before I set the motor in didn’t want to get under it while it was on the hoist. When I got under the truck to install the torque converter bolts there was a 1/4” gap between the original flex plate /flywheel and the converter. I don’t think I installed the flywheel backwards. There were witnesses marks on the flywheel so you could tell which way it was installed. Do I need to get a spacer for the flywheel since it’s a new Optimizer motor? Any body ever had this issue with a new Optimizer motor? ThanksIMG_0860.jpegIMG_0862.jpeg
 
I checked it looks ok? Just worried about the gap between the flex plate and the converter. All the ones I ever did the gap wasn’t that big. I am going to call the transmission shop.
 

Attachments

  • IMG_0864.jpeg
    IMG_0864.jpeg
    130.9 KB · Views: 16
  • IMG_0865.jpeg
    IMG_0865.jpeg
    97.3 KB · Views: 16
Verify as Twisted Steel Performance mentioned, then...

See post #284.
 
The converter can move back and forth some. Is it bound up where it won't move? Possible there is a bearing for a MT left in the crankshaft?
 
Hi guys, I have my torque converter sorted out. I used washers to take up the gap. Thanks for all your input. I do have some more questions pertaining to my build. Snowdrift I really like your post on your 95’ build mines a 95’ also. I did use your idea on routing the passenger side GP wires. Sorry the pics are dark. I also rerouted the return fuel lines. I am trying to source a trans. cooler which is discontinued on the 95’ trucks. I did find one for a 96’ (GM89022535) on Amazon the measurements look the same Not sure on the inlet and outlet connections . I’m going to use 3/8” hose and an -6 fittings. Does any body know if the cooler for a 96’ will work on a 95’? I’m also going to use an after market oil cooler w/ Leroy’s oil cooler line set. Any suggestions on types of oil coolers you guys used would be much appreciated . I did take the oil filter off the new Optimizer to set the motor in and was surprised by the color off the oil Looks like neon yellow. Did the builder use special break in oil.
Could it be synthetic? What are your guy’s thoughts on using synthetic oil in my new motor? I’ll be bothering you guys with more questions as the build goes on. Thanks again.
 

Attachments

  • IMG_0252.jpeg
    IMG_0252.jpeg
    98.6 KB · Views: 5
  • IMG_0251.jpeg
    IMG_0251.jpeg
    143.4 KB · Views: 5
I bought this for my oil cooler.
1722876598778.png

My cooler hoses are PTFE which is correct for the oil cooler. Ratings shown below which far exceed anything necessary. They're very flexible and easy to work with.
1722876741661.png
I'm not a transmission guy but the washers idea concerns me as well. Others with more experience will hopefully chime in.
 
Hi guys, I have my torque converter sorted out. I used washers to take up the gap

No, you don't! You are going to run out of clearance with this disaster of a fix and trash the thrust bearing in the engine and/or transmission pump and the converter. (Severe damage to the rest of engine and/or transmission from the debris will quickly follow.) Under some operating conditions the converter will "balloon" using the space between the engine and transmission. The washers have eliminated that clearance. You need to find out why it's not sliding into the crankshaft as designed.

Again take it apart and figure out why the converter is binding up! Otherwise this will be a very short lived build.
 
NO!!!!!
You will destroy the flex plate & torque converter for sure along with possibly damaging pump in the transmission.

Our buddy from AZ nailed your issue: the crankshaft has to have a pilot bearing installed or there is an incorrect tc there.
This is a major failure waiting to happen
 
Thanks guys for your inputs. As I mentioned in my earlier post the new converter had a 1/4” gap between the flex plate. See the pic in my earlier post. The converter was not binding up. The gaps were never that big on all the ones I have ever done. I talked to the trans. shop that did my trans. And he said that’s not uncommon with a different motor. He said you can install washers to lessen the gap a little, but make sure not to much that the pilot on the converter does not go into the crank for support. I’m not a trans. guy either but every thing I’ve read on the web says there should be about a 1/8” gap between the converter and the flex plate. So I used two washers each to make the gap 1/8”. When I pushed the converter up against the flex plate w/no washers I could see the pump seal and some of the converter shaft. I did spin the converter and it pushed back into the pump so I don’t think it came out of the pump. And then with the converter pushed all the way back w/ the 1/4” gap I could see the some of the converter pilot going in the crank. So that’s why I split the gap difference w /the washers. Again I’m not a trans. guy and do not know how much the converter shaft goes into the pump. Also not sure how far the converter pilot goes in the crank. Snowdrift it also looks like you also had a 1/4” gap between your converter and flex plate w/no issues? Maybe I’ll remove one of the washers. The fist pic is of the washers 1/8”. In the second pic flex plate bolt heads. The shiny thing behind the bolt heads is the crank. Maybe I’ll take these pics up to the trans shop. Got me worried now. Thanks guys.
 

Attachments

  • IMG_0255.jpeg
    IMG_0255.jpeg
    100.5 KB · Views: 8
  • IMG_0256.jpeg
    IMG_0256.jpeg
    119.6 KB · Views: 8
NO!!!!!
You will destroy the flex plate & torque converter for sure along with possibly damaging pump in the transmission.

Our buddy from AZ nailed your issue: the crankshaft has to have a pilot bearing installed or there is an incorrect tc there.
This is a major failure waiting to happen
Will L didn’t see you post before I posted mine. Are you saying there should be a pilot bearing or bushing in the end of the crankshaft like on the manual transmissions?
 
@Goose57 No. The pilot bushing can keep the torque converter from going in against the rear of the crankshaft. This means the crankshaft is pushing the tc back against the transmission pump.

I can’t say it will do damage- I just remember what was taught in school & training classes about it. If pilot bushings never affected automatic transmissions- then no one would ever bother removing them.

@SnowDrift I am on the overly cautious side (aka sky is falling) so maybe you get long life and no problems. Just keep in mind this is how you put it together incas hiccups begin in the future
 
Bear with me guys. A little confused. Will L you stated our buddy from AZ nailed it and a pilot bearing should be in the end of the crankshaft. Maybe I read it wrong. The converter does have a protrusion like a nose cone sticking out sticking out the front that does slide into the back of the crankshaft. Snowdrift did you have a 1/4” gap between the flex plate and the converter before you slid it forward if so mine is the same way. I did say in a previous post that I slid the converter forward and touched the flex plate then spun the converter and slid it back into the pump with no issues so I do not think the converter came out of the pump teeth. But I’m not sure how far the converter can come out of the pump without any issues. Then I seen on the web about the 1/8” gap between the converter and flex plate. Maybe I’m making to big of deal about it. It is only a 1/8” difference. Thanks for helping guys.
Exactly!
With the TC not bolted and washers gone can you slide the TC forward until the bolt lugs contact the flexplate?
Yes. Could moving the converter that far forward cause any issues?
 
IF it won't slide forward and touch the flexplate then what Will is suggesting is that there is something in the end of the crankshaft keeping it from doing so, like a manual transmission bearing. It is normal to have enough forward backwards play so the torque converter can disengage from the crankshaft, for example if you need to change the flexplate. If it won't slide forward enough to touch the flexplate then there's an issue that should be dealt with
 
Will L you stated our buddy from AZ nailed it and a pilot bearing should be in the end of the crankshaft

Looks like @Will L. post is accidentally confusing. There should be no "bearing" in the end of the crankshaft. The pilot bearing is for manual transmissions only, however, if it's put in by mistake or left in after a rebuild it's a problem with the automatic trans Torque Converter, TC. The converter does use the same area of the crankshaft and it's a tight fit.

I would call Yank Converters, as they know WTF they are talking about for converters, and just ask this question about spacing to them. Shameless plug: They make a nice TC even I can't tear up being a carnage thread winner some years...

What is the history on the transmission and TC? I assume the TC fit fine before the engine swap/replacement. Can you compare the new engine crank depth and diameter for the area in question from the old engine?

It's a tight fit for the converter to slide into the crankshaft. It's possible just the blue paint alone may be the problem. Note where the area isn't painted on the Yank red converter:

yank_vs_factory.jpg
 
Back
Top