KieserWillys overdrive

P.S.

Just a a side note out of curiosity. Would changing the gears in the differentials help? And if so what gears would help increase it's speed?

 

If you really do have 3.73 gears your v6 in good shape should have enough butt to run that Jeep at least 75 mph. My 71 has a t14 trans with a dana 18 and known 3.73 axle gears. It will run 75 miles an hour all day long on the interstate and climb 7% grades like that without downshifting. My tires are 31x10.5.

 

Adding an overdrive to an already tall ratio would just hurt it even more...........Mike McRuff says he has 3.73's in his and has no problem.....Personally I think that gear is a little tall. Most Jeeps I see that have the V6 Combo that drive off road have at the minimum 4.27 and lower ratios up to 5.38's At that point the low gears helps to accelerate the Jeep and then once up to speed the 25% Overdrive is welcomed..........I have also gotten away from using the 55 lb flywheel and used the later 35 lb ones. These work will when coupled with a Granny Low truck transmission such as a Ford T-18 with a 6:32 low gear........If your driving just around town and freeway the lighter flywheel with your 3-speed is like night & day to accelerate that little motor.

I would check the motor and then jack it up on Jack stands and run it a little to see if you can hear anything............if while running it and you take the power away by pushing in the clutch and the drive train slows down more quickly than normal then you may have a bind somewhere in the system. Tranny , Transfer case, Drive line U-joints or in the rear axle either gears or bearings............check you oil back there for shavings and also while just after running check the TC and axle housings and bearing ends for heat.........If it's binding up it will generate heat. If you find nothing do the sloped road test........

 

So, last item answered first...Get that tach installed so you can tell the actual engine RPM.

Next question about the T-case intermediate shaft...Yes you can change it while the T-case is in the Jeep but I wouldn't do it that way. You would wind up laying on your back with gear lube dripping in your face while trying to line up the intermediate gear with the case holes and slide the shaft through and oops there went the needle bearings...

Regarding the T-case gearing...In Hi range the gearing is 1:1 so that should not affect your top speed. Only when Lo range is selected will your top speed drop by a factor of 2.46:1.

I think Terry has the best suggestions to diagnose your issues. Get the Jeep up on jackstands front and rear. Leave your front hubs unlocked for now and run the drivetrain up to at least 2000 RPM for for several minutes while listening to the drivetrain noises. After things have been turning for long enough to get warmed up check transmission, t-case and rear axle for excessive heat. Try Terry's suggeation about checking for bind by running the drivetrain up to 2000 RPM and then slip the transmission in neutral and see how quickly the wheels slow to a stop. It should take several seconds at least depending on how heavy your tires and wheels are.


Don

 

Once again thank you for the suggestions, I will be installing tach tomorrow and trouble shooting it from there.

 

i ran my 71 with 3:73's and 33" swampers at just about 80 with the v6 but that was the only time. i was white knuckling it but it did it. this was only in a straight line with no bumps thank god

 

are you sure this has 3:73 gears? i mean did you pull the cover and count the gears? just because you have a tag that states 3:73 someone could have swapped gears and kept the tag on there

 

Yes fellas, I do have some pedal left to push but as mentioned, because of the noise I'm hesitate to push it.
I will also look at the linkage and give it the pedal test as well, anything will help to solve this issue.

 

With all respect, I'm wondering if possibly this isn't just a 'normal' jeep being judged to new car expectations. Jeeps really can seem slower than molasses in modern traffic. AND very noisy.

Sometimes it's all about what you are accustomed to.
I remember a story about a Jaguar owner saying his car ran crappy and had no power after some shop work. It turned out they had simply put a stronger return spring in the accelerator linkage.

 

Sort of a silly thought here, fire up your Jeep for something like 25 seconds, shut it down, check out the temp on the drivers side exhaust manifold then check out the temp on the pass side manifold.
Are they the same temperature?

 

Well PeteL it's like this, when I restored the jeep I wanted to keep everything as close to original as possible, from the oil bath unit to the rebuilt motorola altenator to the Ross steering. When I finally fired it up the first time and took it on a test drive, my expectations where, well let's just say I was a bit nervous, however, after the drive I was pleasently surprised at how well it ran as well as how well it handled with the steering. After driving it off and on now for a few months and getting used to its noises and "personality" I just started questioning it's top speed which lead me to this overdrive thread. I have recieved a lot of informative information and suggestions that I will follow and do. I'm finally on my 7 days off,( I work a 7 and 7 schedule) and now have the time to figure this issue out. If it just so happens to be an old slow jeep thing, hey, I'm fine with that because I love my jeep, but based on other jeeps with the same running gear, and a much better top speed, I would be doing myself and the jeep a great disservice if I don't try to get it running the way it should.

 

"based on other jeeps with the same running gear, and a much better top speed"

If you've had the chance to compare, then I withdraw the question. And I totally applaud your dedication to maintaining it to the original specs.

 

RJ just as a side note . I've been driving my jeep for 32 years now . and I don't think it ever went faster then 75MPH . now I don't drive it that fast anymore . maybe top speed 65MPH . sounds like throttle linkage is off a little . and as mentioned the intermediate shaft is probity the gear noise your hearing . when mine wore it rattled a little on both gear shifters . most of all its a jeep keep it simple and it will run a long time

 

Alright he's an up date on the speed issue, well not really speed since I didn't have a chance to get it
on the road, but I think it was unanimous that I needed to instal a tach, so that's what I did.
installed a tach and adjusted the timing. It was alittle off, but now is correct.
After adjusting the timing I took note of the RPM at idle which was 900. Can someone tell me if this is too low, what should it be or is it just a personal preference? Would this low idle ultimately have an effect on the top speed?

Uncamonkey also suggested taking the temp of both the exhaust manifolds. So I did and there was what I considered a big difference between the driver and passenger side manifolds. Which may be an indicator of something going on with the engine. The passenger side exhaust manifold measured 125 degrees while the drivers side measured 137 degrees, so about a 12 degree difference.

Tomorrow I will do some more suggestions like what Glenn mentioned about checking for
play on the driveshaft. I'll also jack up the back and check the gears just to be sure that they are 3.73, I don't plan on removing the differental cover so I'll have to check it by rotating the rear wheels. Just to be sure, it's one rotation of the tire and cout how many times the drive shaft turns?

hopefully I'll get it on the road with a pace car and see what kind of rpm it's turning at different speeds and gears.

Once again thanks for all the info and suggestions
RJ