I had a TruTrac carrier installed when I had my rear gear changed on my 02 F-150 with a 9.75" rear. Eaton says to use regular gear lube. Any one know why I can't use a full synthetic? I have it my front diff but it has the stock Ford Carrier. The TruTrac in a Tornsen type carrier where there are no clutches just gears.
Detroit TruTrac diff question
- Thread starter kaboom10
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Hi,
it would be wise to check if a GL4 or a GL5 lubricant is needed - Eaton final drives usually call for a GL5
A synthetic lubricant should be suitable in either case
it would be wise to check if a GL4 or a GL5 lubricant is needed - Eaton final drives usually call for a GL5
A synthetic lubricant should be suitable in either case
Explain GL4 and GL5. I can't see why a full synthetic couldn't be used. I switched to 4.88s from the stock 3.55s.
They have different additive levels. GL5 has more Extreme Pressure/Anti-wear than GL4. You can have too much so it would be pertinent to find out what it calls for.
Your diff still employs a hypoid gearset, so a GL5 gear oil will be necessary to protect your gears and even your bearings. What you really need to know is the viscosity of GL5 gear lube that would be best for your conditions. Did Eaton say to NOT use synthetic or just that it was not required? I cannot think of any reason to not use synthetic GL5 gear oil.
Hi,
bmwtechguy - Eaton-Fuller have promoted synthetic lubricants since doing their intensive research leading up to 1992
The correct viscosity is important but they recommended a 75W-90 synthetic for all temperature ranges and over all model types
They also recommended annual OCIs or 100k normal service and 40k for severe service
In my heavy trucks I used 1m kms (620k miles) or four years/sale OCIs
That is why correctly defining what they recommend in this application is important
bmwtechguy - Eaton-Fuller have promoted synthetic lubricants since doing their intensive research leading up to 1992
The correct viscosity is important but they recommended a 75W-90 synthetic for all temperature ranges and over all model types
They also recommended annual OCIs or 100k normal service and 40k for severe service
In my heavy trucks I used 1m kms (620k miles) or four years/sale OCIs
That is why correctly defining what they recommend in this application is important
Thats what I was thinking, was that since the rest of the diff requires GL5, the trutrac should as well, or at least be able to deal with it. But I wasnt sure.. I agree that I dont think you would have a problem with GL5 synth. Im interested in this because I may put a TruTrac in my Vic as opposed to a clutch LSD.
Straight from the Trutrac manual
Quote:
Lubrication
The TrueTrac differential is designed to operate in those lubricants recommended by the vehicle/axlemanufacturer for conventional differentials.
looks like a good synthetic GL5 would work fine.
Quote:
Lubrication
The TrueTrac differential is designed to operate in those lubricants recommended by the vehicle/axlemanufacturer for conventional differentials.
looks like a good synthetic GL5 would work fine.
What would be the right one from Amsoil?
On that model F series, is that a Dana 60 or 70 ?
If so it must be a GL5 lube, as they are a hypoid diff, and IMO it wouldn't hurt going to an xW-110 if used for heavy towing as they are fairly limited in their oil capacity and generate a lot of heat, even just running down the highway.
AFAIK, you are safe running a synthetic lube in a Tru-Trac.
I run an 80W-140 syn lube in a GKN/Salisbury 8HA (English Dana 60 built under licence and an SAE EP90 specified) thanks to the heat generated and limited oil capacity (IIRC, only 2.3 litres)
If so it must be a GL5 lube, as they are a hypoid diff, and IMO it wouldn't hurt going to an xW-110 if used for heavy towing as they are fairly limited in their oil capacity and generate a lot of heat, even just running down the highway.
AFAIK, you are safe running a synthetic lube in a Tru-Trac.
I run an 80W-140 syn lube in a GKN/Salisbury 8HA (English Dana 60 built under licence and an SAE EP90 specified) thanks to the heat generated and limited oil capacity (IIRC, only 2.3 litres)
Its a Ford 9.75" axle. Dont quote me, but Ford probably specs a 75W140 Synth.
I'm not certain if it's a Dana 60 or 70. All i'm certain of is that it's a 9.75". The installer checked before ordering as the 10.25" gets installed on the 7700 model. Yes Ford recommends 75W/140 synthetic but that's based on the stock carrier with clutches.
It seems like this topic was already discussed recently. Here's a link:
https://bobistheoilguy.com/forums/posts/1080980/
https://bobistheoilguy.com/forums/posts/1080980/
Originally Posted By: kaboom10
What would be the right one from Amsoil?
Sounds like a good question for Amsoil Tech. Explain to them what Eaton has said to use (a non-syn). They may have had customer feedback from folks with that type of diff, and may have a special recommended product for best results. If I were to speculate which Amsoil product they will say to use, it would be the 75W-110 or 75W-140 Severe Gear. You won't blow anything up, even if it turns out to be NOT the ideal fluid for your TruTrac. I have been having good results also from Schaeffers #293 75W-90 semi-syn in apps that call for this viscosity. I believe it is the only Schaeffers gear lube that comes in quarts, and is one of the best ones available out there.
What would be the right one from Amsoil?
Sounds like a good question for Amsoil Tech. Explain to them what Eaton has said to use (a non-syn). They may have had customer feedback from folks with that type of diff, and may have a special recommended product for best results. If I were to speculate which Amsoil product they will say to use, it would be the 75W-110 or 75W-140 Severe Gear. You won't blow anything up, even if it turns out to be NOT the ideal fluid for your TruTrac. I have been having good results also from Schaeffers #293 75W-90 semi-syn in apps that call for this viscosity. I believe it is the only Schaeffers gear lube that comes in quarts, and is one of the best ones available out there.
Thanx for the other thread. It explained to me the why of the reason. It's engineered into the operation. I did ask the question of using a TruTrac in the front diff and was told it would cause torque steer. Our first 4wd was open diff front/rear and still gave excellent winter traction.
Originally Posted By: kaboom10
Thanx for the other thread. It explained to me the why of the reason. It's engineered into the operation. I did ask the question of using a TruTrac in the front diff and was told it would cause torque steer. Our first 4wd was open diff front/rear and still gave excellent winter traction.
Plenty of Land Rovers I know (Defenders, Disco's and Rangies ) have Tru-Tracs in the front diff and no one has complained about any untoward steering issues like tugging under power except maybe a slight increase in steering self centreing, as if the castor had increased.
Thanx for the other thread. It explained to me the why of the reason. It's engineered into the operation. I did ask the question of using a TruTrac in the front diff and was told it would cause torque steer. Our first 4wd was open diff front/rear and still gave excellent winter traction.
Plenty of Land Rovers I know (Defenders, Disco's and Rangies ) have Tru-Tracs in the front diff and no one has complained about any untoward steering issues like tugging under power except maybe a slight increase in steering self centreing, as if the castor had increased.
That may be rightly so but rightly so but the manufacturer cautioned me against it. I also liked the savings of not having to purchase one. The front has given me great winter traction with the old gears and just wondered about it before the front end gear change.
Your 9.75 is a Sterling (Visteon) axle, not a Dana. It's a good piece, actually.
I don't think you will have trouble with a synthetic and I don't think the Truetrac will care too much about the viscosity (within the scope of "normal" for the axle and climate), but here's an FYI for you. There have been problems noted with certain synthetics in Trutracs, namely a screeching noise. We had a big discussion on this some time back if you'd care to search. On the aftermarket side, this problem has been cured by switching back to a conventional mineral oil. I have heard reports that Ford has noted the problem on the S-110 axle- equipped F-350 and 450 trucks that use the Truetrac. The bigger problem is that we can't pin down which synthetic oils have the problem. If Eaton knows, they are not telling. We had some reports from users that Amsoil did not cause problems in Truetracs, and it didn't for me either (in an '86 F-250 10.25 Sterling full-float), though I now use LE-607 (a mineral oil) in that truck. I have put RP 75W-140 in a Truetrac equipped Ford 8.8, also with no problems. I also saw Mobil 1 75W90 installed in a 9.75 and the owner reported no trouble. You'll like the Truetrac. It's seamless on dry roads and you'll find it docile on ice as well because it doesn't have that harsh breakaway that a preloaded plate type LS unit has. Wish they made one to fit my F-150s rear axle (10.25 semi-float).
I don't think you will have trouble with a synthetic and I don't think the Truetrac will care too much about the viscosity (within the scope of "normal" for the axle and climate), but here's an FYI for you. There have been problems noted with certain synthetics in Trutracs, namely a screeching noise. We had a big discussion on this some time back if you'd care to search. On the aftermarket side, this problem has been cured by switching back to a conventional mineral oil. I have heard reports that Ford has noted the problem on the S-110 axle- equipped F-350 and 450 trucks that use the Truetrac. The bigger problem is that we can't pin down which synthetic oils have the problem. If Eaton knows, they are not telling. We had some reports from users that Amsoil did not cause problems in Truetracs, and it didn't for me either (in an '86 F-250 10.25 Sterling full-float), though I now use LE-607 (a mineral oil) in that truck. I have put RP 75W-140 in a Truetrac equipped Ford 8.8, also with no problems. I also saw Mobil 1 75W90 installed in a 9.75 and the owner reported no trouble. You'll like the Truetrac. It's seamless on dry roads and you'll find it docile on ice as well because it doesn't have that harsh breakaway that a preloaded plate type LS unit has. Wish they made one to fit my F-150s rear axle (10.25 semi-float).
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Thanx for the info on the axle. I thought it was a Dana. At the moment I'm satisfied with it's operation over all at the moment. I'll run it thru the winter and 4wd during heavy snows. I'm not totally putting off the idea of Amsoil synthetic but it would be next spring at the earliest.
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