Interesting.
I have a Gen 2 engine. I purchased this used Quaife and it came with a coupler, but it had no splines at all(!). So, we added the splined center from an aftermarket sprocket (cut off the teeth, cut down the OD so it would slide into the coupler, then welded it). So, our Plan A is to just install it like a sprocket, with the stock Suzuki nut and washer.
Regarding my coupler, I really don't know its history. I can't guess why it had no splines. Maybe someone had started a project and aborted it.
Another odd thing about my coupler - It was an exact mate/match to the coupler on the GDU. That meant it was all metal-to-metal engagement. The eight white plastic drive pegs would slide in place, but didn't do anything (since the coupler's metal was touching all around). To fix that we are removing a small amount of metal from the coupler's edges. Hope that makes sense.
So, I think we have a good plan, but it would be interesting to see a picture of the locking screws.
Thanks again for the info. Good stuff.
Does anyone know if you can retrofit the SR3 diff onto an SR4?
Sorry, John, I don't know for sure. Anything can be made to work, but I'm guessing you mean with reasonable changes (as opposed to hacking and welding).
If the SR4 is chain drive (that shows how little I know), it's probably not easy. That's similar to the project I'm doing. With chain drive there is plenty of variance regarding distance between the engine and diff, but with the Gear Drive Unit, it must be exact. It needs to be pretty exact laterally, too. It might mean different length half shafts.
Are you asking because you'd like to move away from a messy chain? Just curious.
Does anyone have a schematic of the GDU I could review while reassembling mine? I've got something not aligned so I must have something wrong or missing (like a spacer).
I'd like one so badly I'm willing to pay something.
Thank you.
Russ
Here are a couple of schematics that should help. If they don't get large enough send me and IM with your email address and I will send you the originals (The part numbers are small on the original also.
I hope this helps. No payment necessary... but, if you feel compelled Donations to the Registry are always appreciated. 😉
Let me know if you need anything else.
Charley
Russ, Thank you very much for your Donation. All donations go back into the site to make it better.
Charley
There is a part that was in my GDU and I do not see it in the schematic. It is the odd bearing shown in the picture below.
Since I don't see it in the schematic, it makes me wonder if there have been different versions of the GDU. Maybe I have an early or late version (wild guess).
Or maybe I'm blind and I just haven't found it in the schematic yet.
Is it a part any of you can identify? I might need to order a new one.
I'm close to sending this to a Radical dealer to refresh, but I'm sure that would be painful come payment time. I'd much rather do it myself if possible. I'm stubborn and cheap.
Thank you. - Russ.
To me that looks like part #77 in the diagram (Radical part number TQ0141). That part number does not show up in the Radical On-line store, so it may not be a part they sell to the public. I would double check with a dealership to be certain this is the right part. When I had my GDU overhauled by Spring Mountain the cost was ~$630 plus parts, which seams like a reasonable cost to ensure it is working properly. These GDU's are an amazing piece of engineering. Despite having an external cooler they get really hot in service and keep on working.
Here is a picture of it on the car.
Charley
Charley, you're right. ~$630 is very reasonable. I saw "$1,200" while Googling recently so assumed that was the going rate. Maybe they automatically change all parts or something. 🙂
Thanks for the reply and diagrams via email.
If you need parts, the cost does go up. But, you know it will be done right. Where are you located? I have always had great experiences with Spring Mountain, but most of the Radical dealers can do the work.
Charley
I'm near Atlanta, GA.
Primal Racing (Radical dealer) is at Atlanta Motorsports Park, about an hour north. I've contacted them and may visit them this week.
Your picture helped me get past one of my obstacles.
My last (I think) obstacle is figuring out why the oil pump plate won't fully seat. It hits the bearing about 1/8" before it seats enough for a good seal with RTV. The non-pump plate I have that goes in the same place also will not seal, so I don't think it is a problem with the pump. I may need to split the case to identify the problem.
Could it be an issue with the pump drive not going all of the way into the slot??
Charley
No, because even my non-pump plate (just the plain plate) will not sit flush.
My best guess is the bearing is not recessed down into the case far enough. If the bearing surface (and pump slot) were 1/8" lower, everything would fit fine.
