New Third member gear set??

[eric1h]

Anyone have the "specs" on our third member/gears? I am thinking about trying to pick up another one with 3.89 gears, but not exactly sure what to look for, I am NOT a ford guy(as can be evidenced by my Ls6 swap! lol)

What are you all paying for a new/used rear?

[panozracing]

Tex racing is who made the pkg. Its got an internal billet oil pump that connects to an external cooler. There are lots of gear brands and finishes. I think ours are Motive and polished or something like that.

I bought one used for really cheap but they are on the web for $1200 roughly.

[Fast Viper Dan]

Originally Posted by panozracing

Tex racing is who made the pkg. Its got an internal billet oil pump that connects to an external cooler. There are lots of gear brands and finishes. I think ours are Motive and polished or something like that.

I bought one used for really cheap but they are on the web for $1200 roughly.

When you order the gear set from Tex, make sure you tell them you need the hex EDM'd into the end of the pinion gear for the cooler pump.
I almost missed that when I did a gear swap.

[eric1h]

I have a GT-WC, which doesn't have the oil cooler/pump on it. Does that change anything?

[panozracing]

Sure does...you need to spend more money buying the stuff your missing :-)

[eric1h]

Hey. i don't run Enduro's and to the best of my knowledge, i've never overheated a gear set! ;-) My money would be better spent on driving lessons! ;-)

[Fast Viper Dan]

Originally Posted by eric1h

I have a GT-WC, which doesn't have the oil cooler/pump on it. Does that change anything?

Then you don't need the hex broached in the pinion gear. I would do it anyway if you order from them. You never know what the future will bring.

[PanozDuke]

Eric,
You don't need the internal pump version, just get one of the NASCAR external pumps on ebay. Check with James or Hayes at Wire Wheel to see what they got from Penske for the GTP version of the cars. They used to have a bunch of the coolers with bracket and fan. They might have sold those to Panoz Doc as they were left over from the GTRA parts they got from the school several years ago. Panoz Doc might also have a complete chunk or at least gears.

From memory/rumor I think these are 28 spline Truetrac positraction differentials, but I've never had my GTRA apart to look at it. Not sure what is in the GTS cars, but I think it is the same with provisions for the internal pump (no idea what that entails). I'll bet Kel has had his apart and can be more specific. I do know the housing is not the N case (nodular iron), some of which have the larger pinion bearings and the 31 spline axils as OE. Since our cars do not make repeated standing starts under high traction conditions, the N case, 31 spline axils and bigger pinion bearings would be overkill. The biggest threat is heat so the cooler idea is good when you have higher power and slicks.

Here is what I think I know: The 9 inch gear sets are all the same. The carriers (center section guts) differ by axle spline count (OEM 28, 31, after market can go higher) and pinion bearing and side bearing sizes (I believe there are two OEM choices for each- I know there are two sizes for pinion bearings, standard [M88048-M88010] and Daytona [bigger, HM89443-HM89410]). I believe the side bearings are LM102949-LM102910 (small, 2.8910") and LM603049-LM603011 (large, 3.0625"). You don't have to worry about Ford's three different axel bearing sizes/types. I am guessing we have the smaller combination of carrier side bearings and pinion support bearings. The doubt is in the side bearings they could be the larger.

You might call PAD as I think they would know the pinion and side bearing sizes for the RA and WC cars as well as if they differ from the GTS cars (I don't think they do). Once you know that, you can get the right housing/chunk/pumpkin with correct pinion support and carrier side bearing caps, and Truetrac differential, bearings, etc. Ford F150 trucks were good sources of pumpkins as they were ribbed like ours and they are plentiful. They used the 9 inch 1972-1986 (I think). These are usually (?) the small side and pinion bearings. It really doesn't matter if they are big or small side bearings as long as you buy the new bearings to fit what you end up with. You will need new internals and a good gear set (can be used if still in good shape. I have seen some used NASCAR sets for less than $100 that look like new- ebay).

Anybody know any different, don't let my bad be the last word.

Mike

[NZGTRA17]

Originally Posted by PanozDuke

Eric,

From memory/rumor I think these are 28 spline Truetrac positraction differentials, but I've never had my GTRA apart to look at it. Not sure what is in the GTS cars, but I think it is the same with provisions for the internal pump (no idea what that entails). I'll bet Kel has had his apart and can be more specific. I do know the housing is not the N case (nodular iron), some of which have the larger pinion bearings and the 31 spline axils as OE. Since our cars do not make repeated standing starts under high traction conditions, the N case, 31 spline axils and bigger pinion bearings would be overkill. The biggest threat is heat so the cooler idea is good when you have higher power and slicks.

Mike is right, had mine apart a couple of times. Yes it is a Truetrac and as I recall 28 spline (diassemble and check this). The truetrac is pretty robust so likely to be fine even if it has done lots of hours. I bought a new spare and have regretted it since............ Cant quote bearings numbers and sizes as I have not had to replace any.

I used an aluminium case when I put the diff back together. Figured this would achieve 3 goals in one. Reduce weight, improve heat dissipation and do away with need for pump and cooler (more weight saved). This combination has proven to be absolutely fine in races up to 6 hours in length. Just had the center out of the diff a couple of weeks back and gear set looks mint so heat not an issue with ally case for enduro's in NZ. I am using Redline Heavy Weight Shock Proof Oil though so this will also be making a difference to heat tolerance as it is primo in this application.

If you use an aluminium case, get the case and pinion seal drilled and lockwired in 3 or 4 locations around the seal to stop it popping forward when hot/loaded. Did this to mine this time around as had a minor leak these before this mod (was "auto rust proofing" the rear end of the car).

Dont forget to check the axle seal location prior to slotting the center in............may save you having to pull the center again. What I do now is slip both axles just through the seals prior to putting the center in so that you know they cant slip inwards.

Kel.

[Craig245]

Originally Posted by NZGTRA17

Mike is right, had mine apart a couple of times. Yes it is a Truetrac and as I recall 28 spline (diassemble and check this).

Kel.

My GTRA came with, and still has, 31 spine gears. So check yours. It is easy to check just pull the cover off off the end of either side, slide out the axle and count the splines. It would take less than 5 min after you have the tire off.

Craig