Built transmission failures?

[slowgsr]

Im basically trying to decide on a transmission for my car, its between jacks transmission, or a sheptrans transmission.

Now i have a few options.. Mainly, should i stick with a 4 spider diff, or a welded one. I asked shep this question he said to stick with a welded one as it will be stronger than a 4 spider, and using a Quaife center diff is weak in this application.

About gears, I plan to use the longer evo 1st and the evo 3rd 4th, with a 24.9" tall tire, this will put me at aprox 146mph @ 8400rpm. which is MORE then enough.. I will be more than likely using a 24.5 tall slick. I know what i want as far as gears.

It was recommended by twicks to me to cryotreat the input shaft, intermediate shaft, the 3/4 gearset and hub/slider, along with the center differential case and the front diff spider gears. However, when i ask shep about this, he says they have more success with the REM ISF process (just polishing basically). However, when i look at the services offered by jacks transmission, i see they offer cryo treating.

So which to go with? A cryo treating, or a REM ISF process?

Price is another thing, the transmission from shep is $2675 ($2395 welded center diff) where jacks is $2345 ($2145 welded center diff)

Evo III 1st gear
Jacks + $380
Shep + $75

ISF (polishing process)
Jacks + $300
Shep + $300

Cryo Treating
Jacks + $220
Shep not avail

Im just wondering if anyone on here has had a top of the line shep trans fail, or a jacks transmission fail? and what the setup was like and the reason.

In the end, the shep stage 4 trans will cost $3095 with the rem isf process, 4 spider center diff, and evo 1st.

the jacks trans will cost $3030 with the gear polishing and $-80 to cryotreat. So they are both basically about the same cost.

Any feedback on customer service, quality, etc? And mainly what you guys think of either the REM ISF process of the cyrotreating? Or should i get certain things cryotreated and certain things polished?

Thanks!

 

[twicks69]

I have exploded 5 or 6 Shep transmissions over the years, along with ones from TRE, and other shops. This is the reason why I decided to rebuild my own. Things break no matter what you get done to them. It is just a matter of when.

Somethimes it can be as simple as a factory defect in the material of the gear; even if it is cryoed or REM'ed or shot-peened. It happens. It has happened a few times to me as well.

With pricing each one between Jacks and Shep, you are ending up around the same price, so it essentially comes down to who you want, and shipping costs.

I still personally prefer cryotreating of the shafts I mentioned, the center diff case, and the 3rd/4th gearset and 3/4 hub and slider. The only things you would want REM'ed would be the gears, so that doesn't really do too much. There are many surface finishing processes out on the market nowadays all providing some type of positive benefit to their services, it is up to you to decide. I have tried shot peening, REM, and cryo, and I prefer cryo.

As well, the Evo 3 gears for 3rd and 4th are good parts, but the shorter gear ratio really requires you to rev out the motor to get your mph. In my circumstance, my powerband is from 4000-8400rpms, and I run on a 26" tire and expect to be trapping around 160mph, so the Evo 3 gears really have never been an option for me. I have not personally tried the Evo 3 3rd or 4th gearset yet due to this.

I am still running a late 91-early 92 3rd and 4th gearset and hub/slider/keys/springs/shift rail setup.

If you are willing to rev, the Evo 3 gearset's shorter gear ratio is good for the revvers (2.0, 2.1, 2.2L setups).

Otherwise, I would stick with the "Heavy Duty" Stage 3 gears -- which are late 91-early 92 3rd/4th gearset and hub/slider/keys/springs/shift rail parts. They can handle the abuse, and share the same hub and slider as the Evo 3 parts.

 

[andy4g63]

I have exploded 5 or 6 Shep transmissions over the years, along with ones from TRE, and other shops. This is the reason why I decided to rebuild my own. Things break no matter what you get done to them. It is just a matter of when.

Somethimes it can be as simple as a factory defect in the material of the gear; even if it is cryoed or REM'ed or shot-peened. It happens. It has happened a few times to me as well.

With pricing each one between Jacks and Shep, you are ending up around the same price, so it essentially comes down to who you want, and shipping costs.

I still personally prefer cryotreating of the shafts I mentioned, the center diff case, and the 3rd/4th gearset and 3/4 hub and slider. The only things you would want REM'ed would be the gears, so that doesn't really do too much. There are many surface finishing processes out on the market nowadays all providing some type of positive benefit to their services, it is up to you to decide. I have tried shot peening, REM, and cryo, and I prefer cryo.

As well, the Evo 3 gears for 3rd and 4th are good parts, but the shorter gear ratio really requires you to rev out the motor to get your mph. In my circumstance, my powerband is from 4000-8400rpms, and I run on a 26" tire and expect to be trapping around 160mph, so the Evo 3 gears really have never been an option for me. I have not personally tried the Evo 3 3rd or 4th gearset yet due to this.

I am still running a late 91-early 92 3rd and 4th gearset and hub/slider/keys/springs/shift rail setup.

If you are willing to rev, the Evo 3 gearset's shorter gear ratio is good for the revvers (2.0, 2.1, 2.2L setups).

Otherwise, I would stick with the "Heavy Duty" Stage 3 gears -- which are late 91-early 92 3rd/4th gearset and hub/slider/keys/springs/shift rail parts. They can handle the abuse, and share the same hub and slider as the Evo 3 parts.

This man speaks the truth... He went already thru 15-16 built tranny's...
Way to go Tim. Hope you'll find the right one for you.

 

[slowgsr]

Well, I ordered a shep stage 4, with a 4 spider center and the evo 3 1st and input shaft.. as well as the REM ISF process. Should have it in about 2 weeks. Also a QM twin and DSS driveshaft.

When this one brakes, I will be taking your advice Twicks and learning how to do it myself. However this year, i opted to build the driveline and do some solid suspention and a few other things to get it ready for big power. I plan to just shoot for 500 ish on unleaded 115 still on the stock longblock (minus the arp headstuds and mls gasket). So i hope i will be fine this year. So im just going to try for 125+mph and some nice mid-low 11 sec passes.

I also have a set of 26" tall tires for the car now, MT ET Streets, 235/60/15. These tires are badass, have lots of sidewall flex and are slick like compound.

Afterall.. The cost of a 3K transmission is minimal to the cost of building a 9 sec car, Heck.. A turbo and manifold setup can easily cost that, or a tire and wheel setup gets close depending on what you use. Racing costs money, and if this one blows it blows, hopefully not at my power level though. Im not making quite the near the TQ of you Twicks

I will keep everyone updated on my progress once i start a build thread in a couple weeks.

Thanks for the input

 

[truwarrior]

Nice. I'm having my tranny rebuilt by shep as well. Mines a a 99 GST 5 speed though. Felt kinda wierd talking to the legend himself on the phone Can't wait to see how it drives with a LSD instead of the stock open differential which is starting to fail ever since I got stuck in snow. Hopefully the tranny will be out by this afternoon! Good luck to ya!