rear differential cooler

Discussion in 'transmission and Drive train' started by grumpyvette, Nov 27, 2013.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    now adding a rear differential cooler on a street car or even a drag race cars just some added expense and adding something else to go wrong in my opinion, but on a road racing car,or circle track car, use of both a rear differential cooler, with a fluid pump and heat exchange radiator and use of a slightly deeper increased capacity ,finned differential cover and use of the higher temp rated synthetic differential lubes,(in most but not all cases) well its a long well documented and its a well known way to insure more durability , the fact is that under high torque loads over extended time frames a rear differential tends to build up considerable more heat and the lubricant tends to degrade. most guys change engine oil on a regular basis, most change transmission fluid and have oil and trans fluid coolers, but its not nearly as common for guys to consistently change differential fluids and heat does break down the lubricants properties over time so adding a differential cooler tends to make the rear differential and its bearings and gears last noticeably longer under high stress like road racing.
    in most cases the differential will have a lower drain plug and an upper fill hole that can be used to attach the lines the lower drain should feed the pump the upper fill act as the return fluid point in the circulation, if your differential does not have these access points that allow easy connection of the coolant circulation line connections to the pump and cooling fan, your going to need to drill the case and thread tap or weld in bungs for the line connection points, obviously after carefully checking that a threaded nipple or AN fitting will not protrude thru too cause issues with bearings, supports or moving components inside the differential.

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    http://www.magnet4less.com/product_info.php?products_id=254

    adding a couple high heat range TOLERANT magnets too your differential cover to trap metallic debris won't hurt durability either, the $15 it may cost could save you far more later.
    you can J&B epoxy weld

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    them to the lower outside of the rear cover if your concerned with them potentially getting loose.
    check with your differentials manufacturer for the correct lubricant to use and changing it for new fluid every 50K-60K miles won,t hurt either

    on many rear differentials adding a deeper and more rigid rear cover with heat dissipation fins or in some cases a differential cooler helps durability
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    most guys never even consider that a rear differential takes a great deal of abuse and adding cooling capacity helps durability

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    http://garage.grumpysperformance.co...il-cooler-increases-durability.176/#post-3620

    http://www.fluidcapacity.com/

    http://garage.grumpysperformance.co...ans-cooler-on-a-c4-corvette.10514/#post-44478

    https://www.summitracing.com/parts/til-40-527

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    REAR DIFFERENTIAL LUBES
    http://www.lastgreatroadtrip.com/wp-content/uploads/2010/11/gear-oil-comparison.pdf


    https://www.summitracing.com/parts/der-51008
    viewtopic.php?f=71&t=10690&p=46305#p46305

    http://garage.grumpysperformance.co...ans-cooler-on-a-c4-corvette.10514/#post-44498

    http://www.carid.com/dorman/radiator-fan-assembly.html

    http://garage.grumpysperformance.com/index.php?threads/valve-spring-cooling-via-engine-oil.6491/


    grumpyvetteAdministratorStaff Member
    there have been guys that have the financial resources or connections and or skills to have built an independent rear differential , based on the far stronger DANA 60 vs the factory supplied dana 36 or dana 44 , which are comparable to the G.M. 10 bolt rears, hardly impressive or known for strength or durability, to fit the corvette frame, obviously this takes a good deal of time,effort and money but it also can result in an exceptionally strong rear differential
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    yes its very unfortunate that there's no commonly, available, and reasonably priced, independent rear differential,available to the performance car enthusiasts,with large disc brakes in the compatible width, and easily retro fitted suspension mounts that I'm aware of, in most local salvage yards , similar to the corvette rear suspension, that has the strength of the dana 60 rear differential.
    yes there are custom fabricated solutions, if you have a very healthy bank balance , but nothing based on a dana 60-70- or ford 9" or heavier duty independent G.M. differential
     
    Last edited by a moderator: Aug 14, 2018
  2. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    I was recently asked why Id suggested adding a rear differential cooler to a guys 1970 big block corvette road racing corvette,
    well Id placed the car up on my shops lift and as a general maintenance check I was checking the u-joints and as I got close to the rear differential ,
    I could feel the heat radiate from the rear differential, as my face got close, after checking and lubing the u-joints I wanted to check the rear differential fluid level,
    and asked the cars owner when was the last time he had drained and replaced the rear differential lube....
    I got this deer in the headlights look.... hes raced the car for over 20 years occasionally and as far as he knows its never been checked.....
    now that might be something some of us find hard to believe, but Id bet at least 50% of the guys
    I know that own a c1,c2,c3,c4 corvette have no idea how long its been since the rear differential fluid levels been topped off or even replaced.

    https://www.harborfreight.com/gear-oil-and-fluid-pump-61746.html

    http://www.fluidcapacity.com/

    https://www.homedepot.com/p/Lumax-Multi-Purpose-Hand-Transfer-Pump-LX-1345/302544982?cm_mmc=Shopping|G|HC|D25T|25-31_GARAGE/AUTOMOTIVE|NA|NA|71700000037147756|58700004141485310|92700035285887579&gclid=EAIaIQobChMIvcG9-NLs3AIVRrjACh24mQA3EAQYBSABEgLKn_D_BwE&gclsrc=aw.ds&dclid=CN3snPzS7NwCFaNuwQodk6cHgg

    https://www.homedepot.com/p/K-Tool-...PIPHorizontal2_rr-_-302544982-_-207038142-_-N



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    Last edited: Aug 14, 2018
  3. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    It was about 4 years ago I talked to a guy from the West coast.
    He had a C4 ZR1 pushing over 700 HP.
    He competed in the Silver State Classic.
    He found me my past C4 Corvette dana 44 builds up on Corvette Forum.
    Someone told him to go to Digital Corvette to find me.

    He wanted to run speeds 170-220 mph.
    I suggested a Tilton Oil Cooler & electric pump.

    I lost the Job.

    Dead head set no using that guy.
     
  4. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    The Single most expensive part of a Corvette................
    That IRS Rear differential Grumpy.
     
  5. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  6. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    Rear differentials do get Hot Street Driving with 3.90- 4.10 -4.30 - 4.56- 4.88 Gears Grumpy.
    Ran a 3.90 gear for many years.
     

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