[GUIDE] F35 to F23 (with LSD) Transmission Swap

OptimizePrime

Goblin Guru
I'm at a good point where I believe this can be documented. I'm still trying to figure out how to get the Speedometer to work, so if any you guys have thoughts around this please share! FIXED!

First, why would someone do this?
Well, first is performance. Going from the F35 with Final Drive of 3.82 to the HHR FD which is 4.17 has considerable drivability & torque improvements. The Getrag F23 is known to be able to handle more power than the F35 due to how the shift forks are implemented. F35's are known to break their forks at high torque, low rpm situations. The F23's parts are also more abundant, in the event it does break there are parts available for cheap. That brings me to my second reason, the transmissions are effectively everywhere as they were in a ton of mass produced vehicles. The F35 has become extraordinarily expensive over the past couple of years, going for as much as $1,200 used before shipping to >$3K new. The idea here is that I could take my F35 w/ LSD and swap to the F23 w/ LSD and sell my existing transmission for about the same cost (if not more).

Second, was it worth it?
In summary, I've had about 50miles on the car which includes a dyno session and I can say without a doubt it's made an incredible difference and I'm glad I took the risk. The additional torque due to the FD makes the car feel like it has a lot more power in lower rpms and I don't find myself changing gears as much as the F35 which often felt too low in third and too high of an rpm if I shifted down to second for normal city driving. On the dyno, I put down 350whp and it handled it across many pulls without a sweat. I have yet to sell my F35 w/ LSD and axles so I don't know where I would stand in the netted out cost but it's looking like it'll be close to a couple hundred paid on my part which is totally reasonable.

21398


Here's the process:

I used this link to understand the right years and models, off to ebay I went. You'll notice the year on the HHR makes a difference. If you want the 4.17 you want to look for a manual HHR between the years 2005 - 2008. I found a 2008 with 90k miles and thought that was a STEAL.


Delivered
21399

21400


You could just throw this one with a few minor changes outlined after the LSD part - but if I'm going this far and pulling the engine / trans etc I might as well cough up the money for an LSD and do that also. There are three options for LSD's - one legit LSD, one china LSD, and one insert. The legit LSD is the Quaife ( QDF17B ) which retails for ~$1k, china LSD is the OBX LSD which is ~$450ish which has QC problems and requires additional mods to make it right, and the insert is the Team Green insert. I don't have time for china shyit and the Team Green insert is probably good enough BUT in speaking with Justin at high HP levels it seems to have an issue...so Quaife it is. I found my Quaife NIB on ebay.

I really didn't want to be the one to install the LSD after doing the research, it's not my area of expertise and I just don't have the tools. I called around to everyone in a two hour drive and they either couldn't do it, didn't want to do it, or didn't give me the warm and fuzzies and I might as well do it anyway. For the most part, getting it apart I followed the instructions for the Team Green insert found on youtube


Take your throw out bearing off. Your first mission is to get the cap out, I drilled through mine and then used a little leverage to get the cap and black piece out.
21401


Notice the snap ring, you'll want to save this. The black plastic part is directly under the cap and easy enough to pull out. You'll want to buy a new cap ( 9120610 OR Ford 1311152 )
21402


Getting that bolt out can be a straight up pain in the ass. In the youtube vid you'll see the dudes using vice grips, I'm not lucky enough to use vice grips and not strip the threads. I hated buying the tool to use just once, but made removing and tightening the bolt a breeze and I can sleep well at night.

Kent Moore Input Shaft Anti-Rotation Tool J-44377
21403


This is what she looks like with the top half off
21405

21404


This is where the real fun starts. You can either purchase a bunch of different sized shims and do a bunch of trial and error for the right preload, of you use the shims on your F23 trans which should be close enough. I chose my F23 shims and straight up battled getting the diff bearings off to get to them, you need both sides.

21407


21408


You typically ruin the stock F23 bearings in the process, which is why I had to purchase new bearings. This is the shim you're looking for
21409


Backside was a total b*tch as there is nothing to get leverage with to remove the bearing.
21410


As you can see, I did not have a good time but managed to get it out unscathed.
*UPDATE: DON'T DO THIS, BUY THE RIGHT TOOLS SHOWN BELOW!*
21411


Here is what you need:
KENT MOORE TOOL J-44379 DIFFERENTIAL BEARING PULLER PLATE
KENT MOORE TOOL J-44381 SHIFTER BEARING REMOVER
Total was like $50 from ebay. Well worth the risk / time / effort

Take out your Quaife > insert your shims > press on the bearings > install your ring gear w/ loctite and torque to spec
21412


Take out some assembly lube and put it liberally on your bearings and put her back in
21413


Pick up some anaerobic gasket maker and tighten everything to spec

*** DO NOT FORGET YOUR SPEEDO RING FROM THE STOCK F23 DIFF --- NOT PICTURED HERE! ***
21414


Tighten your bolt and replace the cap - you're done with the LSD!

You can use the F35 throw out bearing and pipe with slight adjustments to get it to stick through the existing hole
21415


21416


At this point, you need to install the DF F23 mounting brackets. I had to get different threaded rear mounting bolts compared to the F35, and used stock bolts for the front transmission mount. I don't have a pic of this part

Once you have it all mounted, you could install new axle seals. I strongly suggest you don't if yours look good as the seals were a source of major leaks when I did mine. The first axle seal I tried to use a large socket and tap the seal in, unfortunately I damaged the seal and it didn't sit correctly (hence the leaks). The second seal I went to the big box store and got a PVC fitting, which was the perfect diameter.

You want a 2 x 1 1/4" fitting
21417


Just hit the pic limit... more to come
 

Attachments

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OptimizePrime

Goblin Guru
Picking up from where I left off, here's what the seal should look like correctly installed.

21418


You then need to extend the reverse light plug
21419


You'll need to grind the shift lever so it doesn't hit your frame
21420


You can use the LNF F35 goblin shift cables but I had to adjust all the fittings to be on the VERY end of the rod to be long enough.

On to the axles. The LNF F35 axles are too large for the F23 trans, you must purchase both the drivers and passengers side axle from a manual 2000 Grand Am

Drivers

Passengers

The passengers side is the long boi. You no longer have the jack shaft and mount that the F35 has. I believe you can get an equal length shaft out of an Isuzu of some type but I didn't research that far enough. These Grand Am axles will fit the LNF hubs no problem
21421


F35 = ~29mm vs F23 is input is ~27mm
21422

21423


You'll notice the F23 axle shafts are significantly smaller in diameter, it didn't seem to make a difference on the dyno....time will tell.

21424


That's it as far as the swap goes. Your speedometer is likely going to be off, I can't seem to get above 20mph on my RPD and vcm scanner. If anyone has any ideas I'm all ears.

I have updated the FD Ratio and VSS Pulses in HPTuners. I have swapped over the speed sensor from the F35 to the F23 .... nothing seems to make a difference. My tachometer works great though.....I'll post back when I have a solution


Solution to Speedometer issues: https://dfkitcar.com/forum/index.php?threads/speedometer-vs-vss-pulses-mile.2503/
 
Last edited:

Tinkles

Well-Known Member
Heads up. Mike Roof is making 500+whp with his Turbo Sunfire(2.2L L61 Ecotec, F23 5-speed). He is running Driveshaft Shop axles and cannot keep them in one piece. He is getting tired of dealing with DSS and just wants a solution. So this might not be a solution for "big" power guys. But if I do remember correctly a few of the higher power J-body guys had the best luck with OEM axles.
 

Dsteinhorst

Well-Known Member
Any reason you didn't go with the Vue trans with the even shorter FD? I'm seeing more of those for sale with better prices.

I currently have a 3.63 FD and have kept my tires tiny because of it.
 

OptimizePrime

Goblin Guru
Heads up. Mike Roof is making 500+whp with his Turbo Sunfire(2.2L L61 Ecotec, F23 5-speed). He is running Driveshaft Shop axles and cannot keep them in one piece. He is getting tired of dealing with DSS and just wants a solution. So this might not be a solution for "big" power guys. But if I do remember correctly a few of the higher power J-body guys had the best luck with OEM axles.
My balls are only big enough for 400-425whp and at $80 a pop I'll burn a few of the oem's first before looking into other options. I'm hoping the low weight of the Goblin helps in this regard. I appreciate the insight and it's great to hear there are some big power guys running the same trans.

Any reason you didn't go with the Vue trans with the even shorter FD? I'm seeing more of those for sale with better prices.

I currently have a 3.63 FD and have kept my tires tiny because of it.
I looked at a few websites which have rpm vs gear vs mph and the 4.17 fd had the best street and strip characteristics, in my opinion. If I burn this trans I may try that trans since I have most of the expensive stuff out of the way.
 

Rauq

Goblin Guru
So what's the scoop on the clutch setup with this swap? I know the LSJ/LNF have a different flywheel bolt pattern from the F23 trans motors, what are the odds the input shaft is the same between the two transmissions?
 

OptimizePrime

Goblin Guru
So what's the scoop on the clutch setup with this swap? I know the LSJ/LNF have a different flywheel bolt pattern from the F23 trans motors, what are the odds the input shaft is the same between the two transmissions?
Oddly enough an LSJ flywheel will fit (pn: 192771286331) on an LNF. I'm using a phoenix friction clutch for an LNF but yea, talk about Frankenstein ..... the F23 trans will work the same with an LSJ ( Justin Reed uses a 3.82fd F23 )
 

Rauq

Goblin Guru
Sorry, the distinction I was trying to make was between the LNF+LSJ (8 bolt cranks) and the L61/LAP/LE5/etc (6 bolt cranks) motors that come with the F23. Because they use different flywheels the pressure plates may or may not be the same, but if the clutch splines are the same, then that would allow the F23 to be swapped into an F35 clutch setup, which sounds to be the case. Thanks for your legwork on this!
 

jayrolls

Well-Known Member
I'm at a good point where I believe this can be documented. I'm still trying to figure out how to get the Speedometer to work, so if any you guys have thoughts around this please share! FIXED!

First, why would someone do this?
Well, first is performance. Going from the F35 with Final Drive of 3.82 to the HHR FD which is 4.17 has considerable drivability & torque improvements. The Getrag F23 is known to be able to handle more power than the F35 due to how the shift forks are implemented. F35's are known to break their forks at high torque, low rpm situations. The F23's parts are also more abundant, in the event it does break there are parts available for cheap. That brings me to my second reason, the transmissions are effectively everywhere as they were in a ton of mass produced vehicles. The F35 has become extraordinarily expensive over the past couple of years, going for as much as $1,200 used before shipping to >$3K new. The idea here is that I could take my F35 w/ LSD and swap to the F23 w/ LSD and sell my existing transmission for about the same cost (if not more).

Second, was it worth it?
In summary, I've had about 50miles on the car which includes a dyno session and I can say without a doubt it's made an incredible difference and I'm glad I took the risk. The additional torque due to the FD makes the car feel like it has a lot more power in lower rpms and I don't find myself changing gears as much as the F35 which often felt too low in third and too high of an rpm if I shifted down to second for normal city driving. On the dyno, I put down 350whp and it handled it across many pulls without a sweat. I have yet to sell my F35 w/ LSD and axles so I don't know where I would stand in the netted out cost but it's looking like it'll be close to a couple hundred paid on my part which is totally reasonable.

View attachment 21398

Here's the process:

I used this link to understand the right years and models, off to ebay I went. You'll notice the year on the HHR makes a difference. If you want the 4.17 you want to look for a manual HHR between the years 2005 - 2008. I found a 2008 with 90k miles and thought that was a STEAL.


Delivered
View attachment 21399
View attachment 21400

You could just throw this one with a few minor changes outlined after the LSD part - but if I'm going this far and pulling the engine / trans etc I might as well cough up the money for an LSD and do that also. There are three options for LSD's - one legit LSD, one china LSD, and one insert. The legit LSD is the Quaife ( QDF17B ) which retails for ~$1k, china LSD is the OBX LSD which is ~$450ish which has QC problems and requires additional mods to make it right, and the insert is the Team Green insert. I don't have time for china shyit and the Team Green insert is probably good enough BUT in speaking with Justin at high HP levels it seems to have an issue...so Quaife it is. I found my Quaife NIB on ebay.

I really didn't want to be the one to install the LSD after doing the research, it's not my area of expertise and I just don't have the tools. I called around to everyone in a two hour drive and they either couldn't do it, didn't want to do it, or didn't give me the warm and fuzzies and I might as well do it anyway. For the most part, getting it apart I followed the instructions for the Team Green insert found on youtube


Take your throw out bearing off. Your first mission is to get the cap out, I drilled through mine and then used a little leverage to get the cap and black piece out.
View attachment 21401

Notice the snap ring, you'll want to save this. The black plastic part is directly under the cap and easy enough to pull out. You'll want to buy a new cap ( 9120610 )
View attachment 21402

Getting that bolt out can be a straight up pain in the ass. In the youtube vid you'll see the dudes using vice grips, I'm not lucky enough to use vice grips and not strip the threads. I hated buying the tool to use just once, but made removing and tightening the bolt a breeze and I can sleep well at night.

Kent Moore Input Shaft Anti-Rotation Tool J-44377
View attachment 21403

This is what she looks like with the top half off
View attachment 21405
View attachment 21404

This is where the real fun starts. You can either purchase a bunch of different sized shims and do a bunch of trial and error for the right preload, of you use the shims on your F23 trans which should be close enough. I chose my F23 shims and straight up battled getting the diff bearings off to get to them, you need both sides.

View attachment 21407

View attachment 21408

You typically ruin the stock F23 bearings in the process, which is why I had to purchase new bearings. This is the shim you're looking for
View attachment 21409

Backside was a total b*tch as there is nothing to get leverage with to remove the bearing.
View attachment 21410

As you can see, I did not have a good time but managed to get it out unscathed.
View attachment 21411

Take out your Quaife > insert your shims > press on the bearings > install your ring gear w/ loctite and torque to spec
View attachment 21412

Take out some assembly lube and put it liberally on your bearings and put her back in
View attachment 21413

Pick up some anaerobic gasket maker and tighten everything to spec

*** DO NOT FORGET YOUR SPEEDO RING FROM THE STOCK F23 DIFF --- NOT PICTURED HERE! ***
View attachment 21414

Tighten your bolt and replace the cap - you're done with the LSD!

You can use the F35 throw out bearing and pipe with slight adjustments to get it to stick through the existing hole
View attachment 21415

View attachment 21416

At this point, you need to install the DF F23 mounting brackets. I had to get different threaded rear mounting bolts compared to the F35, and used stock bolts for the front transmission mount. I don't have a pic of this part

Once you have it all mounted, you could install new axle seals. I strongly suggest you don't if yours look good as the seals were a source of major leaks when I did mine. The first axle seal I tried to use a large socket and tap the seal in, unfortunately I damaged the seal and it didn't sit correctly (hence the leaks). The second seal I went to the big box store and got a PVC fitting, which was the perfect diameter.

You want a 2 x 1 1/4" fitting
View attachment 21417

Just hit the pic limit... more to come
Alex,
Do you know if you can take the Getrag F23 with the 2.2L and swap it for the FPG F35 on the 2.0L?
 

OptimizePrime

Goblin Guru
I'm not sure the nuances on what 'FPG' F35 is but the '08 HHR that I pulled this from was a 2.2L and I swapped it out for the F35 in my 2.0 LNF
 

Rauq

Goblin Guru
No idea what FPG is but there's only 2 basic manual transmissions offered on Cobalts, the F23 (2.2L and 2.4L cars) and the F35 (2.0L cars). They're both equally swappable. The only thing I'm not sure about in going F23 -> F35 is the intermediate shaft, if an LAP would have the block mount for the carrier bearing and how to go from the trans splines to the hub splines. There's 2 gear ratios for each offered in Cobalts and a few others from other vehicles but there's no external differences there.
 
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