This is my 1st post on this site. I have an 89 4x4 3/4 ton with a 3 speed. I have a marine alternator tach that I calibrated by a rough aproximation of the idiling rpms (close enough). I seen to be running at about 1850 rpm at 55 mph. When I try to drive much faster than 60, the engine really sounds like it is winding up & the pedal is down most of the way. I just had the trans & converter replaced with a heavy duty one & the rpms are about the same. There was lots of damage on the old converter & flex plate. Those flex plates are really expensive from Dodge (over $600), but I found one cheap at the local wrecking yard. Does anyone else have a problem with feeling like you have to fight the pedal to go 65+

 

I can cruise all day at 70 mph showing 1850 rpms in OD which your 3 spd does not have. I remember the earlier Dodges having 3.07's in the rear diff which should put your rpm's at about 1850. Check the sticker on the hood it should list your rear diff ratio. If that fails there should be a tag on the bolts holding the rear diff cover on - it will give you the ratio. If you run it up to 70 mph in 3rd (direct) you should read about 2350 to 2400 rpms - if my calculations are correct. Goverened rpm's are 2450 appx. Hope this helps.<br>Bob

 

My 89 4x4 would only run about 74 MPH nailed to the floor. Won't hurt the engine a bit as long as you keep good oil in it. Fuel mileage may suffer a little.

 

I'll echo the above, you aren't gonna hurt your motor puttin it on the floor to run 70, but mpg won't be as good. Without OD you're just kinda stuck

 

is there a aftermarket company that makes a locking TC for the older trannies? that would be really nice to have.<br>DM01

 

i have done the lockup conversion on the gas models. worked fine. it would be a little more complicated on the diesel because of bellhousing adapter and repositiong cross member and assorted linkage. gas models use all factory parts. diesel probably would too.

 

You'd be better off, in my opinion, getting a good reworked A518 with OD in it.<br>Just a thought...<br><br>Bob.

 

bushy i agree with you. that is what i did. now why is it taking you so long to try the governor spring? would really like to see your face when you do.

 

Thanks for all the replies. I do have 3:07 ratio axles. When I had my tranny guy rebuild my 3-speed I asked about swapping to an o/d trans &amp; he said it would cost a lot to do the conversion &amp; I would then be faced with possibly re-gearing both axles to 3:55. The new tranny really hooks up under load &amp; is extra heavy duty. The truck is my dedicated boat puller &amp; has dents, no a/c &amp; regular cab. If this were my daily driver I would buy a 96 or 97 x-cab with a stick. This is not my first diesel, I started with a 6.2 chevy pickup that ran well, but lacked 4wd &amp; didn't have much torque under load. This is definitly my last truck with an automatic. I really like how easy it is to work on the Cummins over the V8's.

 

I had considered putting an aftermarket overdrive in my 89 while I had it. I think Gear Vendor or someone makes one that will bolt to the back ot the trans or trans case if I remember right.
You might look at a taller gear like 2.72 in the rear or something like that.

 

[quote author=fishermansteve link=board=9;threadid=12345;start=0#122276 date=1049069182]<br>Thanks for all the replies. I do have 3:07 ratio axles. When I had my tranny guy rebuild my 3-speed I asked about swapping to an o/d trans &amp; he said it would cost a lot to do the conversion &amp; I would then be faced with possibly re-gearing both axles to 3:55. The new tranny really hooks up under load &amp; is extra heavy duty. The truck is my dedicated boat puller &amp; has dents, no a/c &amp; regular cab. If this were my daily driver I would buy a 96 or 97 x-cab with a stick. This is not my first diesel, I started with a 6.2 chevy pickup that ran well, but lacked 4wd &amp; didn't have much torque under load. This is definitly my last truck with an automatic. I really like how easy it is to work on the Cummins over the V8's.<br>[/quote]you will not have to re-gear with od trans. i have been running 3.08s and od for almost 50k. gross towing weight of 11k including truck is no problem. just take it out of od on monteagle mt. you will love an od with this set-up. if one doesnt think it will pull it look at my sig. it still gets 20 mi per gal on freeway.