Powertrax Grip Pro vs Detroit Trutrac for Ford 9"

Tim C

Tim C

Wizard
Joined
Jan 22, 2007
Location
Fayetteville
Not 4x4 related but someone here has to have some experience with this. I'm looking to un-drag car my 67 Fairlane and make it more of a cruiser. I've been slowly working towards that goal. Probably the next step is to get rid of the full spool in the 9" and go with a limited slip. I need one that will work with my 35 spline moser axles. I dont really want a clutch type posi, and the only ones I've seen have been twice the price of the gear type anyway. I have some experience with the trutrac, I had one in my old 03 f250 diesel tow rig and liked it, and I put one in a 8.8 for a friend's 67 cougar and he has no complaints. I see powertrax has a Grip Pro posi out now that uses the spiral gear setup like the trutrac. Its going in a roughly 4000 lb car that will have about 500hp/530tq once I get my stroker motor built.

My only experience with Powertrax stuff was with the old lock right lunchbox lockers and I was less than impressed with their performance. Has anyone here used the Grip pro and how is it working out for you, I know this is different than a wheeling toy. Price wise the grip pro is 50 to 100 cheaper and will ship out sooner than the trutrac. I didnt see either listed on ECGS's website, and I'm not wanting a locker on this car since its going to be a street toy now.
 
If they're both the helical gear style limited slips, then they should both work the same. I wouldn't be afraid to use the PowerTrax Grip Pro. I've got one truck with a Detroit locker in the rear and one with a Yukon Grizzly locker. They both work the same and I can't tell a difference between the two...they're both equally aggravating :D

I actually want a Trutrac, Grip Pro, or the factory Dodge 2500 limited slip for the rear of my Duramax too. I definitely don't want a full locker for pulling a loaded gooseneck.
 
I bought a nice used Detroit for my car off of EBay for $200. He says that it was only used once, really hard for 500 miles. He was in Mooresburg. He had 31 and 35 spline used units. If your Fairlane has a 9” this could be an option. I don’t know if that is streetable enough for your situation.
 
thecj3man said:
I bought a nice used Detroit for my car off of EBay for $200. He says that it was only used once, really hard for 500 miles. He was in Mooresburg.
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When I was contemplating some 9" hybrid axles ("609") a few years back, there were shit-tons of NASCAR parts available... complete 3rds with all the good stuff in every gear imaginable for 1/4 of new. Like you said, most was used only once... real hard :driver:
 
The NASCAR stuff would be a Detroit locker. I've had a trutrac but not the power grip. I'd think either would be fine. I'd shy away from a locker, just like you're thinking.

Just use an open carrier. 1 wheeled burn outs for days!
 
Yea, the reason the car has a spool is because I hated driving it on the street with the locker before, I said I'd rather it be locked all the time Vs random unlocking and the tail wagging while shifting gears. Now that it's full time street again I want a posi. Just trying to decide if it's worth saving 75 to 100 on the grip pro Vs trutrac or if this is another you get what you pay for deal, lol

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I debated if I wanted a full on locker in my 55 bel air. I thought hard about the trutrac and might go that way in the future if the locker isn’t worth the hassle. I have drive a couple other Detroit locker cars and didn’t find them too unbearable. But, they were all automatics.

I put an Auburn Posi in my dad’s Nova and he has been very happy with it. I don’t know if there available or not in 35 spline.
 
thecj3man said:
I debated if I wanted a full on locker in my 55 bel air. I thought hard about the trutrac and might go that way in the future if the locker isn’t worth the hassle. I have drive a couple other Detroit locker cars and didn’t find them too unbearable. But, they were all automatics.

I put an Auburn Posi in my dad’s Nova and he has been very happy with it. I don’t know if there available or not in 35 spline.
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In my experience a locker and a stick transmission suck on the street. If you shift in a turn the car can be a handful. Sometimes it felt like a dog wagging his tail. It would kick out left then right then left as I went through the gears.

The trutrac is nice, I had iron my last tow rig a 6.0 powerstroke with a 6 speed. I just wasn't sure of powertrax's quality.

Not sure if auburn has a posi for 35 splines but a quick look at summit shows all the clutch style limited slips in that spline are 1000 to 1200 dollars. The helical grip pro is 475 and a trutrac is 550. I just wondered if anyone had experience with the grip pro or if I should spend the extra money on the trutrac. It's not much money but every bit I don't have to spend is better

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I have a grip pro in the d44 rear on my xj. Tru trac in the d30 front. The Grip pro was one I put in when they first came out and Powertrax gave me one as a test unit. It functions just like a tru track, Has held up well to my healthy 4.6 stroker (I killed 2 trac locks) and I have no complaints. I will see if I can get you a price and availability on a 9" one. We have sold a bunch of the dana 44 ones and I have had no complaints.
 
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So, it has been almost a year, what did you decide to go with. I am thinking hard about my decision to go with the Detroit locker in my 55. I like the two wheel John Force burn outs, but regular driving is interesting with the manual trans.
 
thecj3man said:
So, it has been almost a year, what did you decide to go with. I am thinking hard about my decision to go with the Detroit locker in my 55. I like the two wheel John Force burn outs, but regular driving is interesting with the manual trans.
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Well I got a trutrac for Christmas. It's installed and working good. I'm sure the grip pro would be fine too.

I had a trutrac in my old tow rig, 03 f250 6.0 6 speed, in both it and the Fairlane it's seamless on pavement. Drives like an open diff as far as turns and parking, it'll still leave two rubber strips if you side step the clutch. You can't go wrong on a street car with this style diff in my opinion.
 
Tim C said:
Well I got a trutrac for Christmas. It's installed and working good. I'm sure the grip pro would be fine too.

I had a trutrac in my old tow rig, 03 f250 6.0 6 speed, in both it and the Fairlane it's seamless on pavement. Drives like an open diff as far as turns and parking, it'll still leave two rubber strips if you side step the clutch. You can't go wrong on a street car with this style diff in my opinion.
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Thanks for the feedback. I am strongly considering the Trutrac and also have been studying up on Detroit Lockers. I never realized that the spring rate inside the locker could be changed. Looking at back, I am pretty sure the locker I got has a heavy duty spring in it. It is doesn't always unlock going around corners. The car has to be in neutral or the clutch pushed in or it drives like a spool and is making the car hop through the turns. I did find several places to recommend a very light spring for street driving so that the ratchet mechanism will release easier. The only problem is a set of springs is 100$ and that is money that can be put towards the Trutrac.
 
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