Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Differential- 4 speed & 5 speed difference

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
Differential- 4 speed & 5 speed difference  Rate Topic 
AuthorPost
 Posted: 12-27-2005 01:24 pm
  PM Quote Reply
1st Post
nvandal
Member
 

Joined: 08-02-2005
Location:  
Posts: 58
Status: 
Offline
Can anyone tell me how the rear end gear ratios were different between the four and five speed? Also, how would I know which I have. I pulled a five speed Getrag tranny and rear axle off a 75. I'd like to be certain which differential I have

Thanks muchly,

norm Vandal

Back To Top PM Quote Reply  

 Posted: 12-27-2005 05:38 pm
  PM Quote Reply
2nd Post
Judson Manning
Member


Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Status: 
Offline
Norm,

The 5-sp cars have a 3.45:1 ratio while the 4sp cars have a 3.73:1 ratio, both look VERY similar. 

Confusing matters is the early 4sp cars had different brakes (Girling/Lockheed) and a different sized input flange.

The 'extra' 5sp gear is really a lower first gear to give the impression of an overdrive at top is still 1:1.   The Supra 1st gear is lower than the 4sp trans, but almost identical in 2nd, 3rd & 4th. 

3.45:1 is a bit tall for a high revving 2.0 car.  The hot ticket is a 3.73 RE in a car with either 5sp transmission.

Back To Top PM Quote Reply

 Posted: 12-28-2005 01:04 am
  PM Quote Reply
3rd Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 976
Status: 
Offline
The "hot ticket" for driving on the freeway with either stock transmission is the 3.45:1.  Can you imagine driving across the country at 4200 rpm with a 1:1 diff and only making 70 mph? Forget it, I'll fly.

Back To Top PM Quote Reply  

 Posted: 12-28-2005 01:25 pm
  PM Quote Reply
4th Post
Judson Manning
Member


Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Status: 
Offline
Exactly...

Who in their right mind would want to be in a car that doesn't meet 1975 roll-over requirements, has no side-impact protection, no crush zones, no air-bags, and could easily drive under an 18-wheeler?

On top of that who wants to be in a car long distance that has no sound deadening, no lumbar support, no cruise control, a marginal sound system, and no climate control?

I guess we're all a bit insane....

360miles one-way is my record going to Jacksonville, FL loaded up for a race.  I have no idea how Aaron Gross drove from Atlanta to NY for Nationals without going insane, but he did it.

With the lack of torque supplied by our beloved 907, there is a real limit to how 'tall' we can make the gears.  I'm afraid our LBC will never be much of a highway crusier.

Perhaps we should all have a JH and an Interceptor?

 

Back To Top PM Quote Reply

 Posted: 04-11-2009 07:20 pm
  PM Quote Reply
5th Post
Gary Martin JH 15371
Member
 

Joined: 03-12-2005
Location: Portland, OR
Posts: 98
Status: 
Offline
I have a question about the early and late 4 speed differentials. I have two 74 Mark 2 cars. Both have the larger driveline flange on the differential. My 2nd car is John Kimborough's damaged car, and the rear differential housing is bent. I want to replace the diff so it will roll and drive. I know where there are several 73 mark 1 parts cars in the area but I'm sure they have the smaller diff flange. Can the flange be interchanged between the two? I know about the crush pinion sleeve, and that doing this swap might, or wouuld require the gear mesh to be re-adjusted. Is this possible for a reasonably talented home mechanic? Or should I just look for a later 4 speed diff? I know I could just swap the drive line as well, but I would rather keep the later one with the larger U joints. Anyone know where I might find one in Oregon, Washington area? Gary 

Last edited on 04-11-2009 07:23 pm by Gary Martin JH 15371

Back To Top PM Quote Reply  

 Posted: 04-12-2009 05:03 am
  PM Quote Reply
6th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 976
Status: 
Offline
I have a spare diff from a '74 4 speed. I think the flange diameter is 3 3/4" but I'll check tomorrow. Come and get it, free. I have no idea of the condition but it has been living outside for at least 4 years.

Kurt

Back To Top PM Quote Reply

 Posted: 05-09-2009 04:39 pm
  PM Quote Reply
7th Post
Jim DeClerck
Member


Joined: 03-16-2005
Location: Huntington Beach, California USA
Posts: 73
Status: 
Offline
Just read these posts and I guess I'd be classified "insane".  In '82, when I bought 14482, I was transferred from the San Francisco area to Chicago.  I drove her all the way, passing through Rocky Mountain N. P. in June.  It snowed up there over 12,000 ft.   Then the sun came out and it was fine.  No mechanical issues except a failing U-joint on the prop shaft in Minnesota.  Just drove on through and had it repaired in Chicago.  A few years later I drove her on to Rochester, NY for another transfer.  Had the body worked on, new paint, seats, radio, carpet, water pump, etc.  The kids learned stick shift in her.  Then had her shipped back to CA in '91 for the final transfer.  Still own her, occasionally drive her and enjoy her. 

Back To Top PM Quote Reply  

 Posted: 07-07-2009 04:59 pm
  PM Quote Reply
8th Post
sjensen24
Member
 

Joined: 08-05-2005
Location: Brooklyn Park, Minnesota USA
Posts: 77
Status: 
Offline
I found 15092 in Fresno, CA about five years ago and drove it home to Minneapolis.  It was actually a fairly comfy ride.  Alternator problems on the way had me driving through North Dakota without headlights and laying up overnight to charge batteries.

Back To Top PM Quote Reply

 Posted: 06-24-2010 02:26 pm
  PM Quote Reply
9th Post
thesnyder
Member
 

Joined: 04-05-2005
Location: Portland, Oregon USA
Posts: 4
Status: 
Offline
San Diego to Portland in August.  Car turned over 100,000 miles on that trip, no trouble anywhere.  Put the top down in Ashland and drove the last 5 hours enjoying the zen of the Jensen-Healey at a comfortable 70 mph.  Stock four speed 74 vin 15390.  Must of been a good week at the plant.  

Back To Top PM Quote Reply  

Current time is 11:47 am  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Differential- 4 speed & 5 speed difference Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems